No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Iberian Rock Lizards (Lacerta monticola cyreni) Assess Conspecific Information Using Composite Signals from Faecal Pellets
Abstract
A field and laboratory study was performed to analyse the role of excrement deposited on the substrate in intraspecific communication of the Iberian rock-lizard (Lacerta monticola cyreni). In the field, lizards selected specific sites on rocks to deposit faecal pellets, probably in order to facilitate visual location of pellets by conspecifics. Differential tongue flick rates to chemicals presented on cotton swabs demonstrated that male lizards can detect and discriminate between self-produced scents from faecal pellets and those of other conspecific males. In a subsequent experiment, male lizards were tested in a chamber with two platforms containing a faecal pellet of other male on one side and a control artificial pellet on the opposite side. Males spent significantly less time on the side containing the faecal pellet, suggesting that the decision of where to stay may depend on the presence of faecal pellets. Smaller males moved less than larger males on the experimental side whereas on the control side body size did not influence the proportion of time moving. The ability to discriminate chemicals from faeces, and the effects of faecal pellets on lizard behaviour, suggests that faeces might act as composite signals (visual and chemical) in the intraspecific communication of this lizard.
... Chemical intraspecific communication is widespread and prominent in lizards [1][2][3][4][5], and this is based on chemical cues arising from different sources [6]. For example, compounds with the function of semiochemicals can be secreted by the skin or by large specialized external holocrine epidermal glands (femoral, preanal, or precloacal glands) [1,7,8], but semiochemicals can also come from internal cloacal glands and be secreted onto the surface of feces or scats, as feces are deposited by the lizard [9][10][11][12][13][14][15][16][17]. Semiochemicals from different sources can provide detailed information on conspecifics, and many species can use two or more of these sources to produce multiple chemical signals. ...
... Some of these lipids may have an important role in communication [22,25,35], although proteins alone also allow at least self-recognition [46]. On the other hand, male I. cyreni lizards deposit fecal pellets on prominent high locations on rocks, acting as a composite visual and chemical signal [11]. Similarly to femoral secretions, uncharacterized chemicals in these feces allow sexual discrimination, self-recognition, discrimination of familiar vs. unfamiliar males, and signaling of male body size [11,15]. ...
... On the other hand, male I. cyreni lizards deposit fecal pellets on prominent high locations on rocks, acting as a composite visual and chemical signal [11]. Similarly to femoral secretions, uncharacterized chemicals in these feces allow sexual discrimination, self-recognition, discrimination of familiar vs. unfamiliar males, and signaling of male body size [11,15]. However, as in other lizards, it is unknown which specific compounds from feces may function as semiochemicals and the information that they can provide. ...
Chemosensory communication in lizards may be based on multiple compounds coming from multiple sources. Both secretions from external epidermal glands, and internal cloacal glands and feces are known to convey information (sex, familiarity, body size, etc.) for conspecifics. However, although some compounds in femoral gland secretions have been characterized and their function examined, there is very little information on potential semiochemicals in cloacal products and feces. More importantly, it is not well-known whether the compounds and information from multiple sources are redundant, complementary, or different. We analyzed the lipids in femoral gland secretions and feces of male Carpetan rock lizards (Iberolacerta cyreni) and examined which compounds might predict body size. We found many compounds in feces, mainly steroids, alkanes, and branched alkanes, while the main compounds in femoral secretions were steroids and fatty acids. The body size of males was related to the proportions of some alkanes, alkenes, and terpenoids in feces, while it is related to the proportions of some steroids and fatty acids in femoral secretions. There were also differences in the chemical profiles of feces of males and females, which may allow sex recognition. Therefore, femoral secretions and feces may both inform on males’ sex and body size, but the chemical bases of this information are different depending on the source.
... On the other hand, feces contain products from cloacal glands and from the digestive and urinary systems and are also recognized as a source of semiochemicals in some lizards (Bull, Griffin, & Johnston, 1999a;Bull, Griffin, & Perkins, 1999b;Labra et al., 2002;López, Aragón, & Martín, 1998). Fecal pellets can also be used as visual signal to mark territories (Duvall, Graves, & Carpenter, 1987;López et al., 1998), but less is known about their chemical composition (Bull, Griffin, & Johnston, 1999a) and the role of feces in lizards' social behavior. ...
... On the other hand, feces contain products from cloacal glands and from the digestive and urinary systems and are also recognized as a source of semiochemicals in some lizards (Bull, Griffin, & Johnston, 1999a;Bull, Griffin, & Perkins, 1999b;Labra et al., 2002;López, Aragón, & Martín, 1998). Fecal pellets can also be used as visual signal to mark territories (Duvall, Graves, & Carpenter, 1987;López et al., 1998), but less is known about their chemical composition (Bull, Griffin, & Johnston, 1999a) and the role of feces in lizards' social behavior. In males of Liolaemus tenuis lizards, the chemical compounds present in the feces seem to be important in males' self-recognition (Labra et al., 2002). ...
... To obtain the scent stimuli, before the beginning of each trial, two males of each age class were randomly chosen and their femoral secretion and feces were collected and mixed to be applied directly on the strip papers. To minimize the potential role of visual signals of feces (Duvall et al., 1987;López et al., 1998), fecal pellets were disaggregated and the content extended on the paper. Each male donated material for four different females; two females received the femoral secretion and two females received the feces of the same male. ...
Chemical communication plays an essential role in several social and reproductive behaviors of many animals. In lizards, the main sources of semiochemicals are femoral or pre‐anal gland secretions and feces. In male lizards Psammodromus algirus, there are age‐related differences in the chemical composition of femoral gland secretions and in the reproductive strategies, with older males defending territories and females, while younger males adopting sneak‐mating strategies. Females flee more often from mating advances of young males than from those of old males, which are more successful in obtaining matings. This suggests that age discrimination of males may be important for females. We tested here whether females showed differential chemosensory responses to chemical cues (femoral gland secretion and feces) of males of two age classes, and whether females use information from substrate scent marks of males of different ages to select where to stay. We found that females elicited more tongue‐flicks to the secretion and feces of old males than to control or secretion and feces of young males. Also, the time spent by females on a scented paper depended on the treatment, suggesting that females tended to spend more time on scent marks made with femoral secretions of old males. Adult females seemed capable to discriminate between young and old males based on chemical cues alone and showed more interest in scents of old males. However, substrate scent marks did not seem to entirely determine site selection by females, suggesting that females might need additional cues to perform the choice. These results can be explained by the different age‐dependent reproductive strategies of males, which can affect differentially to females.
... One possible behavioural tactic of lizards to enhance visual detectability is by producing piles of faecal pellets (geckos: Carpenter and Duvall, 1995;Shah et al., 2006;skinks: Bull et al., 1999;Fenner et al., 2015) or alternatively, by favouring prominent positions as defecation site, such as high placed substrates (lacertids: Aragón et al., 2000;Moreira et al., 2006). For instance, field observations by López et al. (1998) indicate that Iberian rock lizards (Iberolacerta cyreni) tend to deposit their faecal pellets on the tip of rocks. Remarkably, empirical evidence on defecation site preferences of lizards is scarce, with a number of gaps in our understanding of lizard defecation behaviour remaining. ...
... Remarkably, empirical evidence on defecation site preferences of lizards is scarce, with a number of gaps in our understanding of lizard defecation behaviour remaining. First, it is still uncertain whether lizards prefer certain defecation sites, such as rock-tips (López et al., 1998), to enhance visual detectability, or whether these site preferences are a mere consequence of lizards selecting for rock-tips for different reasons than signal efficiency alone. In a field setting, rock-tips can also provide better opportunities for thermoregulation, foraging, escaping predators, and direct visual communication with conspecifics (Carrascal et al., 1992;Salvador, 1993, 1992). ...
... Our findings show that P. melisellensis lizards prefer to defecate on the largest rock in the environment. Earlier field observations indicated that lizards tend to select for specific locations to deposit their faecal pellets (Carpenter and Duvall, 1995;Fenner and Bull, 2010;López et al., 1998;Shah et al., 2006), yet, due to the field conditions in which these observations were made, it has remained difficult to untangle the exact origin of this behaviour. For instance, it is uncertain whether some species select rock-tips as defecation sites because it may increase the visual detectability of their faecal deposits (López et al., 1998), or because it facilitates the search for prey (Diaz and Carrascal, 1991), the escape from predators (Marshall et al., 2016), direct visual communication with conspecifics (Marshall and Stevens, 2014) or overall thermoregulation (Bauwens et al., 1996;Castilla and Bauwens, 1991;Martín et al., 1995). ...
Many animals use their excrements to communicate with others. In order to increase signal efficacy, animals often behaviourally select for specific defecation sites that maximize the detectability of their faecal deposits, such as the tip of rocks by some lizard species. However, the field conditions in which these observations are made make it difficult to reject alternative explanations of defecation site preference; rock tips may also provide better opportunities for thermoregulation, foraging, or escaping predators, and not solely for increasing the detectability of excrements. In addition, we still know little on whether lizard defecation behaviour varies within-species. In this laboratory study, we take an experimental approach to test defecation site preference of Podarcis melisellensis lizards in a standardized setting, and assess whether preferences differ between sexes, and among populations. Our findings show that in an environment where all stones provide equal thermoregulatory advantage, prey availability, and predator pressure, lizards still select for the largest stone in their territory as preferred defecation site. Moreover, we demonstrate that lizards' defecation preference is a strong conservative behaviour, showing no significant intraspecific variation. Together, these findings corroborate the idea that lizards may defecate on prominent rocky substrates in order to increase (visual) detectability of the deposited faecal pellets.
... The characteristics of microhabitats selected by L. monticola (mainly rock boulders and screes) (MARTÍN & SALVADOR, 1997b) are propitious for this type of composite signalling (visual and chemical) (ALBERTS, 1992). Thus, in the field, lizards selected specific sites on rocks (relatively higher positions) to deposit faecal pellets, probably in order to facilitate visual location of pellets by conspecifics (LÓPEZ et al., 1998). A lizard could initially locate and approach the signal source visually, then investigate it or the possible surrounding scent marks through chemosensory channels. ...
... A lizard could initially locate and approach the signal source visually, then investigate it or the possible surrounding scent marks through chemosensory channels. In fact, differential tongue flick rates to chemicals presented on cotton swabs demonstrated that male lizards can detect and discriminate between self-produced scents from faecal pellets or from the femoral pores and those of other conspecific males (LÓPEZ et al., 1998;ARAGÓN et al., 2000ARAGÓN et al., , 2001b. Moreover, behavioural tests further showed that faecal pellets and other scent marks also may influence whether a male lizard stays or leaves when encountering them, but that this response depends on body size relative to the depositor of the faecal pellet (LÓPEZ et al., 1998;ARAGÓN et al., 2000ARAGÓN et al., , 2001d. ...
... In fact, differential tongue flick rates to chemicals presented on cotton swabs demonstrated that male lizards can detect and discriminate between self-produced scents from faecal pellets or from the femoral pores and those of other conspecific males (LÓPEZ et al., 1998;ARAGÓN et al., 2000ARAGÓN et al., , 2001b. Moreover, behavioural tests further showed that faecal pellets and other scent marks also may influence whether a male lizard stays or leaves when encountering them, but that this response depends on body size relative to the depositor of the faecal pellet (LÓPEZ et al., 1998;ARAGÓN et al., 2000ARAGÓN et al., , 2001d. This suggested that the decision of where to stay may depend of the presence of scents of other males and on the relative fighting ability of both males, estimated from chemical cues alone. ...
... Chemicals with the function of pheromones are secreted onto the surface of the feces or scats, probably from cloacal glands, as feces are deposited by the lizard. These chemicals may serve for territorial scent-marking in some lizards (Duvall, Graves, & Carpenter, 1987;Carpenter & Duvall, 1995;López, Aragón, & Martín, 1998;Bull, Griffin, & Johnston, 1999;Bull, Griffin, & Perkins, 1999;Aragón, López, & Martín, 2000;Bull, Griffin, Bonnett, Gardner, & Cooper, 2001). Chemical signals from scats of Australian tree skinks (Egernia striolata) and Stoke's skinks (Egernia stokesii) (Fam. ...
... In Iberian rock lizards (I. cyreni) (López et al., 1998), western fence lizards (Sceloporus occidentalis) (Duvall et al., 1987), and western banded geckos (Coleonyx variegatus) (Carpenter & Duvall, 1995), feces are deposited on visually conspicuous sites and have an aggregated spatial distribution, such that the visual location of the pellet at long distance might further elicit the search for chemical signals from the scat or from nearby scent marks. Fecal chemicals of adult male rock lizards (I. ...
... Fecal chemicals of adult male rock lizards (I. cyreni) allow for self-recognition, discrimination of familiar vs. unfamiliar males, and signaling of male body size, thus suggesting that feces act as a composite signal (visual and chemical) in territorial marking (López et al., 1998;Aragón et al., 2000). ...
Pheromones are chemicals involved in intraspecific communication in many animals. Reptiles rely more on their chemical senses than any other vertebrate class and many behavioral studies suggest that chemical cues (sex pheromones) are important in the
communication and reproduction of many reptiles. However, although there are some descriptions of glandular chemical products that might potentially function as pheromones, there has been little research that has linked these chemicals with their roles in communication and reproductive behavior. Some recent studies, mainly with snakes and lizards, have started to reveal the importance of specific pheromones in reproduction and sexual selection. We review the results of experiments showing that
pheromones are involved in sex and individual recognition, territoriality, intrasexual aggression between males, mate choice, and reproductive decisions. Pheromones not only inform on the presence and sex of a conspecific, but also may provide reliable
information on the characteristics, quality, and health state of the sender, which other individuals may use in their reproductive decisions. We are also starting to understand how chemical communication systems evolved in reptiles by examining both the
diversity of pheromones and the underlying physiological and endocrinological mechanisms involved in their production and expression. These physiological mechanisms, specially the alternative roles of some chemicals in other metabolic functions such as the maintenance of the immune system, may also explain how
pheromones have evolved to be used as reliable sexual signals in reproduction.
... En el campo se observó que dentro de las áreas de campeo, las lagartijas depositaban los excrementos en sitios seleccionados del hábitat, concretamente en posiciones elevadas sobre las rocas y más altas que las esperadas por azar, facilitando su localización visual por parte de otros conespecíficos. De esta manera, los excrementos son utilizados para el marcaje territorial como señales compuestas presentando efectos comunicativos visuales independientes de los de las feromonas asociadas (LÓPEZ et al., 1998). En otro experimento en el laboratorio se comprobó que el comportamiento de los machos que entran en un terrario se modifica si están presentes excrementos de otros machos. ...
... Pero además, las respuestas comportamentales de los individuos hacia las marcas territoriales de otros conespecíficos, no sólo dependen de la posesión de un territorio (MATHIS, 1990), sino de otros factores, tales como la talla corporal (MATHIS & SIMON, 1994;ZUCKER & MU-RRAY, 1996;ARAGÓN et al., 2000). En el caso de L. monticola, la proporción de tiempo moviéndose en presencia de los excrementos de otros machos depende de la talla, y por tanto de la habilidad competitiva, del macho experimental (LÓPEZ et al., 1998). Además, la respuesta a los estímulos químicos de los excrementos depende también del tamaño corporal, ya que el número total de extrusiones linguales emitidas en respuesta a los excrementos de otros machos decrece significativamente con la talla del macho experimental (LÓPEZ et al., 1998). ...
... En el caso de L. monticola, la proporción de tiempo moviéndose en presencia de los excrementos de otros machos depende de la talla, y por tanto de la habilidad competitiva, del macho experimental (LÓPEZ et al., 1998). Además, la respuesta a los estímulos químicos de los excrementos depende también del tamaño corporal, ya que el número total de extrusiones linguales emitidas en respuesta a los excrementos de otros machos decrece significativamente con la talla del macho experimental (LÓPEZ et al., 1998). Los machos mayores, presumiblemente dominantes, no buscarían más información sobre el macho detectado porque la probabilidad de éxito en una disputa agonística es alta. ...
Intraspecific communication in reptiles by chemical signals: The use of reliable signals in deciding the behaviour.-Many vertebrates use their nasal chemical senses in many contexts, such as fora- ging, intraspecific communication, or predator recognition. The importance of chemical signals is based on that they are energetically very efficient, transmit and hold information in absence of the signaller, and can work in darkness and at long distance. It has been well established that tongue extrusions of snakes and many lizards provide a quantifiable and objective response to chemical stimuli. Thus, by measuring the in- crease in tongue-flick rate in response to a chemical stimuli we can know whether there is detection of the chemical signal, and by analysing the differences in tongue-flick rates to several stimuli we can know whet- her there is discrimination of these. I review several experiments with lizards and amphisbaenians where I show how chemical signals have evolved to be reliable and to be used in intraspecific communication, mainly in sex and individual discrimination, competitor assessment during agonistic interactions, territory marking and mate choice. With this approach, it seems to be proved that reptiles rely on chemical signals not only to detect and discriminate scents, but also in deciding behaviours, thus, contributing to stabilise the so- cial systems.
... Es una especie poligínica ). Los machos territoriales marcan sus dominios vitales con las secreciones femorales (López y Martín 2005a) y con excrementos (López et al. 1998; y defienden territorios cuyo tamaño tratan de incrementar aumentando su tasa de movimientos y así solapar su área de campeo con más hembras ). Normalmente, el uso de esta estrategia territorial provoca encuentros agonísticos entre machos (Martín y Salvador 1993), estando el resultado de estas peleas condicionado por el tamaño relativo de la cabeza y determinando su posición en la jerarquía de dominancia (López y Martín 2002b;. ...
... A good species to test this hypothesis is the Carpetan rock lizard Iberolacerta cyreni. In this species, territorial males scent mark their home ranges with femoral gland secretions and feces (López et al. 1998;. Territorial males defend their home ranges and try to enhance their surface area to overlap with the home range of more females ). ...
Title: Consequences of the individual variation of the chemical signals of the males of the Carpetan lizard (Iberolacerta cyreni) for their reproductive success, the social organization, the females' preferences and the offspring's phenotype
In this thesis, we studied the effects on reproductive success, social organization, female's preferences and the offspring's phenotype produced by the variability of males' chemical signals in lizards using, as a model species, the Carpetan lizard (Iberolacerta cyreni). In the first chapter, we analysed the effect of an immune challenge on the expression of chemical and visual ornaments of males. In a natural population, we injected bacterial lipopolysaccharide into a group of males and measured the change in the intensity of the expression of the visual and chemical signals. The results suggested the existence of a trade-off between the physiological regulation of the immune system and the production of chemical and visual ornaments. In the second chapter, we checked if the immune challenge caused a decrease in reproductive success. Our results showed that reproductive success increased with body size (or age) but not with the experimental treatment. This suggests the existence of a reproductive strategy of "terminal inversion" in the "suboptimal" males. In the third chapter, we tested whether an experimental increase in the quality of chemical signals from males influenced the use of space by females and the social hierarchy among males. We supplemented a group of males with vitamin D3 before the mating season and released them together with a group of females in a semi-natural enclosure so that they could copulate and interact freely. The results suggested that, despite the role of signals in sexual selection, competition between males is a key factor in accessing females. In the fourth chapter, we checked whether the preference of females for provitamin D3 is because this molecule is a valuable resource for females in gestation. We supplemented two groups of pregnant females with provitamin and vitamin D3 and we studied the potential benefits they could have for them, for their eggs and their offspring. Our results suggested that the potential sensory bias of females could be related to the physiological needs of females. In the fifth chapter, we verified the existence of maternal effects induced by the availability of provitamin and vitamin D during pregnancy. We tested the offspring of mothers supplemented with provitamin and vitamin to locomotor performance assays and trials to measure their tendency to dispersion. Our results showed the existence of an anticipatory maternal effect in response to postnatal habitat conditions. In the sixth chapter, we assessed how the quality of the maternal environment during pregnancy and the existence of a stressful post-natal environment affect the personality of the offspring. We treated the offspring of females supplemented with vitamin D with corticosterone, simulating a stress situation. We evaluated the coherence and the repetitiveness of its activity, use of refuge and assumption of risks. Our results suggested that the mother's diet and postnatal environment conditions affect the expression of personality.
... En diversas especies de lagartijas, se ha determinado que las señales químicas intervienen en el reconocimiento propio (Alberts, 1992; Labra y Niemeyer, 1999), de los conespecíficos (i.e., sexual; Labra et al., 2001;Barbosa et al., 2006;Vicente y Halloy, 2016) y de los individuos familiares y no familiares (Alberts y Werner, 1993;Cooper, 1996;Aragón et al., 2001a;2001b). Además, las señales químicas pueden informar sobre el tamaño corporal (López et al., 1998;Aragón et al., 2000;Carazo et al., 2007), la edad (López et al., 2003;Martín y López, 2013), el estado de salud (López y Martín, 2005;Martín et al., 2007) y la condición reproductiva (Cooper y Vitt, 1984;Cooper y Pérez-Mellado, 2002). ...
... Estas secreciones químicas pueden ser liberadas pasivamente o activamente a medida que la lagartija se mueve por su área de acción (Mason, 1992;Wyatt, 2003). Las secreciones de las glándulas femorales (Dipsosaurus dorsalis, Alberts, 1992;Iguana iguana, Alberts y Werner, 1993) o las heces (Lacerta monticola cyreni, López et al., 1998) pueden intervenir en la delimitación y en el anuncio del área de acción. Además, la producción y deposición de las secreciones químicas puede verse influida durante la estación reproductiva, cuando los niveles de hormonas sexuales aumentan (Martins et al., 2006). ...
Chemical self-recognition in Liolaemus pacha (Iguania: Liolaemidae) is influenced by season.
ABSTRACT. Chemical signals play an important role in social and sexual recognition in several lizard species. Here, we investigated whether the lizard Liolaemus pacha can recognize their own chemical scents (i.e., self-recognition) from a control. In addition, the effect of reproductive vs. post-reproductive season was considered. We experimentally tested scent discrimination, using the terrarium previously occupied by the individual and an untreated terrarium as a control. We estimated the latency to the first tongue flick and the number of tongue flicks for 10 min. Only during the post-reproductive season, L. pacha lizards produced more tongue flicks when exposed to own scents than to a control, suggesting self-recognition. Chemical signals could be used as territorial scent marks, mediating the advertisement of boundaries. We discuss the lack of self-recognition during reproductive season. Lizards showed a short latency to the first tongue flick and a high number of tongue flicks during the reproductive season, which might be associated with physiological changes related mainly to reproduction.
RESUMEN Las señales químicas juegan un papel muy importante en el reconocimiento social y sexual de muchas especies de lagartijas. En este trabajo, se investiga si la lagartija Liolaemus pacha puede reconocer sus propios estímulos químicos (i.e., auto-reconocimiento) con respecto a un control. Además, se consideró el efecto de la estación reproductiva vs. post-reproductiva en dicho reconocimiento. Se testeó experimentalmente la discriminación química usando el terrario previamente ocupado por el individuo focal y un terrario neutral como control. Se estimó la latencia al primer lamido y el número de lamidos en 10 minutos. Sólo durante la estación post-reproductiva, las lagartijas L. pacha produjeron más lamidos al estar expuestas a sus propios estímulos químicos que en el control, sugiriendo auto-reconocimiento. Las señales químicas intervendrían en el marcado y el mantenimiento de los límites territoriales. Se discute la ausencia de auto-reconocimiento en la estación reproductiva. Las lagartijas tar-daron menos en lamer y lamieron más durante la estación reproductiva, lo que podría estar asociado a los cambios fisiológicos relacionados con la reproducción.
... They can derive from specific organs such as femoral (Alberts 1993), precloacal (Cooper et al. 1994), or urodaeal glands (Cooper et al. 1986, Cooper & Garstka 1987, Cooper & Trauth 1992. Less specific sources can also be involved such as the exudates of the body surface (Mason & Gutzke 1990, Bull et al. 2000 and feces (Duvall et al. 1987, Werner et al. 1987, Carperter & Duval 1995, López et al. 1998, Bull et al. 1999a, 1999b, Aragón et al. 2000. ...
... Many vertebrates use feces as visual and chemical signals to mark their territories, and sometimes the chemical effect is reinforced using urine (Alberts 1992b). Lizard feces contain digestive and urinary products, and may constitute chemical but also visual signals (e.g., Duvall et al. 1987, López et al. 1998). However, the experiments performed with L. tenuis were designed in such way as to avoid feces as visual cues. ...
Experimental tests were conducted with the lizard Liolaemus tenuis (Tropiduridae), to determine the potential sources of pheromones used in its chemical communication, centered in the phenomenon of self-recognition. During the post-reproductive season, feces of both sexes and secretions of precloacal pores (present only in males) were tested. Stimuli were presented to lizards spread on rocks, and the number of tongue-flicks (TF) to the rocks was used as a bioassay to determine pheromone recognition. Feces contained pheromones involved in self-recognition, since lizards showed less TF confronted to rocks with suspensions of their own feces than with suspensions of feces of conspecifics or with water (control). In order to assess the chemical nature of self-recognition pheromones, feces were submitted to a sequential extraction with three solvents of increasing polarity, thereby obtaining three feces fractions. There were no differences in TF towards rocks with different fractions with own feces. Additionally, lizards showed similar TF to rocks with fractions of own and conspecific feces, suggesting that the separation procedure broke up a complex stimulus into parts that were not active individually as pheromones. Finally, males did not discriminate between precloacal secretions from themselves and from another male. It is possible that these secretions convey information relevant to or detectable by females only.
... Shah et al. (2006) reported scat piling in the gecko, Nephrurus milii; however, they found conspecifics displayed no obvious behavioural responses to those scats. Other lizards deposit scats in prominent positions where they can be easily seen by conspecifics, such as on exposed rocks (López et al. 1998), thus enabling lizards to use scats as both a visual and chemical signal (Duvall et al. 1987;López et al. 1998). In Australia, the scincid genus Egernia has an unusually high number of species reported to produce scat piles close to their refuge sites (Bull et al. 1999Chapple 2003). ...
... Shah et al. (2006) reported scat piling in the gecko, Nephrurus milii; however, they found conspecifics displayed no obvious behavioural responses to those scats. Other lizards deposit scats in prominent positions where they can be easily seen by conspecifics, such as on exposed rocks (López et al. 1998), thus enabling lizards to use scats as both a visual and chemical signal (Duvall et al. 1987;López et al. 1998). In Australia, the scincid genus Egernia has an unusually high number of species reported to produce scat piles close to their refuge sites (Bull et al. 1999Chapple 2003). ...
Context
The deliberate accumulation of faeces or scats in one location is a common behaviour used for social signalling. The endangered pygmy bluetongue lizard, Tiliqua adelaidensis, is a solitary-living species that appears to use scats as social signals. Previous studies have found that these lizards approach burrows more cautiously if there is a conspecific scat present and behave differently to scats from male and female conspecifics, indicating that these lizards can recognise scat-based conspecific cues. For endangered species, understanding how an animal uses and responds to chemical cues has the potential to become a powerful tool in conservation management.
Aims
To investigate whether these solitary lizards might be using scats as social signals by testing whether scats were being deposited in a non-random pattern designed to maximise their exposure to the nearest neighbour conspecifics.
Method
In the present study, we investigated the spatial pattern of scatting behaviour by pygmy bluetongue lizards in the field.
Results
Scats were consistently deposited in one direction that was significantly aligned with the nearest occupied burrow of a neighbouring lizard. The same deposition sites were used when previous scats were either destroyed by rain, or experimentally moved to a different location. Male lizards deposited scats significantly closer to their own burrows when neighbours were closer.
Key conclusions
The results were consistent with the lizards using scats to advertise their presence and status. The scat-deposition patterns observed in the present study suggest that scats are used as an olfactory signal associated with social organisation of pygmy bluetongue lizards.
Implications
Current plans for the conservation management of this endangered species include translocations. By understanding how these lizards respond to, and use chemical cues, we may be able to use this knowledge to aid in translocation programs, e.g. by pre-establishing territories for individuals before they are introduced into the population.
... They can derive from specific organs such as femoral (Alberts 1993), precloacal (Cooper et al. 1994), or urodaeal glands (Cooper et al. 1986, Cooper & Garstka 1987, Cooper & Trauth 1992. Less specific sources can also be involved such as the exudates of the body surface (Mason & Gutzke 1990, Bull et al. 2000 and feces (Duvall et al. 1987, Werner et al. 1987, Carperter & Duval 1995, López et al. 1998, Bull et al. 1999a, 1999b, Aragón et al. 2000. ...
... Many vertebrates use feces as visual and chemical signals to mark their territories, and sometimes the chemical effect is reinforced using urine (Alberts 1992b). Lizard feces contain digestive and urinary products, and may constitute chemical but also visual signals (e.g., Duvall et al. 1987, López et al. 1998). However, the experiments performed with L. tenuis were designed in such way as to avoid feces as visual cues. ...
Experimental tests were conducted with the lizard Liolaemus tenuis (Tropiduridae), to determine the potential sources of pheromones used in its chemical communication, centered in the phenomenon of self-recognition. During the post-reproductive season, feces of both sexes and secretions of precloacal pores (present only in males) were tested. Stimuli were presented to lizards spread on rocks, and the number of tongue-flicks (TF) to the rocks was used as a bioassay to determine pheromone recognition. Feces contained pheromones involved in self-recognition, since lizards showed less TF confronted to rocks with suspensions of their own feces than with suspensions of feces of conspecifics or with water (control). In order to assess the chemical nature of self-recognition pheromones, feces were submitted to a sequential extraction with three solvents of increasing polarity, thereby obtaining three feces fractions. There were no differences in TF towards rocks with different fractions with own feces. Additionally, lizards showed similar TF to rocks with fractions of own and conspecific feces, suggesting that the separation procedure broke up a complex stimulus into parts that were not active individually as pheromones. Finally, males did not discriminate between precloacal secretions from themselves and from another male. It is possible that these secretions convey information relevant to or detectable by females only
... Researchers commonly use differential tongueflick (TF) rates in reptiles to assess vomerolfaction discrimination capability and response to chemosensory stimuli (Cooper et al. 1996;López et al. 1998;Saviola et al. 2013). Differential TF rates in lizards have been associated with mate choice (Font et al. 2012;Baeckens et al. 2017a), sex discrimination (Cooper et al. 1996;Gonzalo et al. 2004), speciesspecific recognition (Barbosa et al. 2006;Labra 2011), and conspecific familiarity (Font and Desfilis 2002;Gabirot et al. 2012). ...
Intraspecific communication via chemosignals has been linked to important natural history aspects in lizards, including honest signaling tied to reproductive success and conspecific displays of sociality. Chemosignals can be used over significant spatial and temporal parameters, allowing for inconspicuous interaction by some species. This type of cryptic communication is not easily detected, but researchers can obtain baseline lizard signaling capabilities by quantifying tongue-flick (TF) rate toward conspecific scents. We tested chemosignaling behavior in endangered Guatemalan Beaded Lizards (Heloderma charlesbogerti) by evaluating TF response toward same-sex and opposite-sex conspecific stimuli and control treatments. Our suspected sources of pheromones for determining conspecific scent recognition were shed skin and used substrate. Age and reproductive cycle of trial subjects had no discernable effect on TF rate, but sex was a significant factor. Both males and females displayed differential TFs between treatments from opposite-sex and same-sex donor individuals. Male lizard TF response was significantly different between all treatments, including controls. Females had lower and less pronounced differential TFs towards treatments than males, as female TF response was only significantly different between opposite-sex stimuli towards control and same-sex stimuli treatments. We conclude that nonvolatile chemosignals are present in H. charlesbogerti biomaterials, with the degree of behavioral response varying depending on sex and presented stimuli. Our study not only adds to our understanding of intraspecific chemosignaling in helodermatid lizards, but also provides information that could lead to more comprehensive conservation programs for H. charlesbogerti.
... These feces have been found to allow conspecific and sex discrimination in several skinks (Bull, Griffin & Perkins, 1999;Bull, Griffin & Johnston, 1999;Bull et al., 2000Bull et al., , 2001, lacertids (Aragón, López & Martín, 2000;Nisa-Ramiro et al., 2019), iguanians (Duvall, 1979(Duvall, , 1981Duvall, Graves & Carpenter, 1987;Labra et al., 2002;Wilgers & Horne, 2009) and geckos (Carpenter & Duvall, 1995). Fecal pellets may even be used for territorial scent marking (Duvall, Graves & Carpenter, 1987;Carpenter & Duvall, 1995;López, Aragón & Martín, 1998). For example, in some Australian skinks (Egernia striolata and E. stokesii), individuals respond more strongly to chemicals from feces of unfamiliar conspecifics than to their own scats (Bull, Griffin & Perkins, 1999;Bull, Griffin & Johnston, 1999). ...
Background
Many animals rely on chemical cues for intraspecific communication. This is especially important in fossorial animals because visual restrictions of the underground environment limit the opportunities for visual communication. Previous experiments showed the ability of the amphisbaenian Trogonophis wiegmanni to discriminate between several categories of conspecifics based on chemical cues alone. However, in contrast with many other reptile species, T. wiegmanni does not have external secretory glands, but uses uncharacterized secretions from the cloaca in intraspecific chemosensory communication.
Methods
Using gas chromatography-mass spectrometry (GC-MS), we analyzed the lipophilic compounds from feces and cloacal products freshly extracted from the cloaca of male and female T. wiegmanni . We identified and estimated relative proportions of the compounds found, and tested for intersexual and body-size related differences.
Results
We found a total of 103 compounds, being some steroids (mainly cholesterol and cholestanol), some alkanes and squalene the most abundant and frequent. Further, we found intersexual differences, with males, especially larger ones, having higher proportions of several alkanes between C 13 and C 24 and of squalene than females, which had higher proportions of several steroids and also of nonacosane and methylnonacosane than males. We compared these findings with secretions of other animals and discuss the potential role of these compounds and their variations in intraspecific communication of amphisbaenians.
... In fact, even employing a broad definition of sociality, no species of lacertid lizards have been found to form stable aggregations [37]. Moreover, despite of the observations that faeces of some species, such as Iberolacerta cyreni, are deposited on visually conspicuous sites and have an aggregated spatial distribution [38], there is no previous information on the existence of scat piling in lacertid lizards. ...
Background
In lacertid lizards from Mediterranean islands, frugivory is common, particularly under prey scarcity, a characteristic of small islands. In several populations, the diet of the Balearic lizard, Podarcis lilfordi, is extremely variable and includes fleshy fruits. However, frugivory is sporadic and there are very few examples of dominant fruit consumption.
Results
We describe the existence of an extraordinary fruit consumption of a single plant species, the juniper, Juniperus phoenicea, by the Balearic lizard, P. lilfordi. In addition, for the first time in Lacertidae, we describe the existence of scat piling in the population of these lizards inhabiting Cabrera Island (Balearic Islands, Spain). Scat piling was detected in an isolated location with hundreds of scats deposited by several individuals at a particular place.
Conclusions
The high population density of lizards at the island of Cabrera and the great versatility of foraging behavior of this species allows us to hypothesize that scat piles could act as an attractor for numerous individuals, that is, as inadvertent social information. If that hypothesis is correct, it would result in the concentration of several individuals foraging on a single or a few ripening plants. We cannot, however, rule out that individuals concentrated due to the scarcity of ripening plants in other areas, without any influence of the presence of several lizards, as attractors to the site. Our findings modify previous descriptions of the diet of the Balearic lizard in Cabrera made with smaller samples. In some places and periods of the year, frugivory on a single plant species can be extremely intense and only large sample sizes of scats allow to find these particular trends in the foraging ecology of insular lizards.
... This means that, for each group, the sample was made of several pieces of paper towel with feces and was composed of a mix of individual scents. We collected feces instead of femoral secretions because feces are also commonly used in lacertid lizard to simulate olfactory responses (López et al. 1998;Aragón et al. 2000;Moreira et al. 2008) and chemical communication based on femoral secretions is relatively less important in this species (Gabirot et al. 2008). Samples were collected using surgical pliers cleaned with alcohol and rinsed with sterile water between each population. ...
Organisms can gain information about predation risks from their parents, their own personal experience, and their conspecifics and adjust their behavior to alleviate these risks. These different sources of information can, however, provide conflicting information due to spatial and temporal variation of the environment. This raises the question of how these cues are integrated to produce adaptive antipredator behavior. We investigated how common lizards (Zootoca vivipara) adjust the use of conspecific cues about predation risk depending on whether the information is maternally or personally acquired. We experimentally manipulated the presence of predator scent in gestating mothers and their offspring in a full-crossed design. We then tested the consequences for social information use by monitoring offspring social response to conspecifics previously exposed to predator cues or not. Lizards were more attracted to the scent of conspecifics having experienced predation cues when they had themselves no personal information about predation risk. In contrast, they were more repulsed by conspecific scent when they had personally obtained information about predation risk. However, the addition of maternal information about predation risk canceled out this interactive effect between personal and social information: lizards were slightly more attracted to conspecific scent when these two sources of information about predation risk were in agreement. A chemical analysis of lizard scent revealed that exposure to predator cues modified the chemical composition of lizard scents, a change that might underlie lizards’ use of social information. Our results highlight the importance of considering multiple sources of information while studying antipredator defenses.
... Different organs, femoral, precloacal, or urodaeal glands, can produce pheromones (Cooper and Trauth 1992;Cooper 1994;Sánchez-Martínez et al. 2007;Labra 2008). Less specific sources can also be involved such as the exudates of the body surface and feces (Mason and Gutzke 1990;López et al. 1998;Bull et al. 2000;Aragón et al. 2006;Labra 2008). ...
The reproductive cycle of Galapagos giant tortoises has primarily been studied in captive individuals via noninvasive methodologies, including hormonal studies, radiographs, and ultrasound. During the annual reproductive cycle, mating peaks occur during the hot season months (December–June), followed by nesting during the cool season (June–December). Females dig flask-shaped holes in the soil typically in flat areas at lower elevations where soil suitable for digging accumulates. Females deposit 1–26 eggs and close nests with a mixture of urine, feces, and soil, which then dries into a hard cap, which seals in moisture and provides a protective layer for developing embryos. Rate of development and sex of the embryos depend on the temperature of the nest: when incubation temperatures are high (above 29.5°C) embryos become female and when temperatures are low (below 28°C) male. Eggs hatch after between 90 and 270 days of incubation. Young remain in the nest for up to 1 month until all eggs have hatched and consumed their yolk reserves. Hatchlings then dig an exit hole and emerge from the nest.
... Different organs, femoral, precloacal, or urodaeal glands, can produce pheromones (Cooper and Trauth 1992;Cooper 1994;Sánchez-Martínez et al. 2007;Labra 2008). Less specific sources can also be involved such as the exudates of the body surface and feces (Mason and Gutzke 1990;López et al. 1998;Bull et al. 2000;Aragón et al. 2006;Labra 2008). ...
Reptiles have physiological, morphological, and behavioral adaptations that allow them to survive in desert environments, at high altitudes and in cold climates, such as the Patagonia region in southern Argentina. Knowledge of the ecology of Patagonian lizards is limited and fragmentary. The objective of this chapter is to present a synthesis of the current state of knowledge of the ecology of Patagonian lizards with regard to the use of (1) spatial resources (home range, use of microhabitats), (2) temporal resources (daily and seasonal patterns of activity), and (3) trophic resources (diet and nutrition strategies). We also discuss inter- and intra-species interactions, including predation, seed dispersal, parasitism, behavior, and resource partitioning.
Keywords: Diet. Habitat. Use time. Behavior. Predation. Parasitism. Seed dispersal. Competition. Resource partitioning. Teiidae. Liolaemidae. Phyllodactylidae. Leiosauridae.
... Different organs, femoral, precloacal, or urodaeal glands, can produce pheromones (Cooper and Trauth 1992;Cooper 1994;Sánchez-Martínez et al. 2007;Labra 2008). Less specific sources can also be involved such as the exudates of the body surface and feces (Mason and Gutzke 1990;López et al. 1998;Bull et al. 2000;Aragón et al. 2006;Labra 2008). ...
Understanding how human beings perceive and interact with the local herpetofauna is fundamental for its conservation. In this chapter, we propose looking forward to the local ecological knowledge (LEK) of the Patagonian lizards, especially the “matuasto”. The preliminary analysis of ethnohistorical sources points out the relevant role of “matuastos” in the cosmologies of the original people from Patagonia, often considered as immortal, selfish and harmful beings. Field reports agree on the warning not to disturb these territorial lizards; otherwise, they would react aggressively with bites. The recorded stories account for frequent biting events on sheep. The local perception on “matuastos” as harmful beings would provoke an attitude of caution and rejection towards them. This work provides a first overview on the relationship of lizards and the people from Patagonia while constituting an initial step for future research.
... We predicted that, if lizards were capable of TIR on the basis of proteins alone, then subject lizards' chemosensory exploration rates in the 'other1-other2' treatment should increase in the dishabituation trial compared with the last habituation one, in order to gain more information about the novel stimulus. Indeed, we learned from previous studies on this species (López et al. 1998;Aragón et al. 2000;López and Martín 2011) and the closely related I. monticola (Moreira et al. 2006) that TF rate usually increases in response to a novel stimulus from conspecifics, supporting the idea that novelty should elicit a raise in TF rate. ...
Individual recognition (IR) plays an important role in modulating social
interactions of several animal species. IR may work at two fundamental
levels: at class-level (CIR), if it allows group membership identification (e.g.
familiar/unfamiliar), or at individual-level (true IR; TIR), if it allows uniquely
recognizing conspecifics. Direct and indirect evidences suggest that many
lizards are able to recognize conspecifics, notably using the secretions from
femoral glands, specialized epidermal structures located in the cloacal region.
Such secretions are made of a mix of lipids and proteins, the latter having
been poorly studied but hypothesised to convey identity-related information.
Using male Iberian Rock lizards, we set up bioassays to test the role of the
protein fraction in IR, and specifically whether lizards: (1) can detect proteins
from femoral glands, (2) can recognize their own proteins from those of an
unfamiliar male (CIR) and (3) can distinguish between two unfamiliar protein
signals (TIR). We found that femoral proteins can be actually detected, and the
protein signal was enough to allow self-recognition, but not to distinguish
between two unfamiliar males. These outcomes support the hypothesis that
proteins from lizard femoral glands are used in intraspecific communication,
at least at CIR level. The lack of TIR detection has three possible
explanations: (1) finer IR abilities are actually absent in this species; (2) TIR requires a more complex and complete chemical signal or (3) a more
prolonged and complete set of previous interactions among individuals is
needed to lead to familiarity and TIR.
... In a mate-choice context, chemical signals, which are used as territorial scent marks in many species, have an important role in assessment of the traits of potential mates (Johansson & Jones, 2007), such as quality (Moore, 1988), reproductive or health state (Kavaliers & Colwell, 1995), or genetic compatibility (Penn, 2002). Male lizards mark their territories with faeces and femoral gland secretions (López et al., 1998;Martins et al., 2006). Femoral secretions are composed of proteins and many lipophilic compounds, forming a waxy mixture. ...
Female Carpetan rock lizards (Iberolacerta cyreni) might assess the quality of males from their chemical signals. Females select areas scent marked by males with secretions containing high proportions of provitamin D to ensure mating with high-quality males. However, an alternative explanation might be that females are not choosing a mate, but that females have a pre-sensory bias for chemical cues of vitamin D in the food and are, in fact, assessing habitat quality to obtain direct benefits of increasing the intake of vitamin D. We evaluated experimentally the possible benefits of a nutritional supplement of provitamin D or vitamin D in pregnant females for their clutches and offspring. However, we did not find large differences between treatments, except in the lower body condition of juveniles of mothers supplemented with provitamin D. We also tested the chemosensory interest of females in the scent of males to study the existence of a sensory bias; this response decreased when the amount of dietary vitamin D exceeded their needs. The results suggest that there are no reproductive benefits in the intake of additional vitamin D and that the potential sensory bias to scents of males could be related to the physiological needs of the females.
... Increasing the total quantity of the deposited glandular secretions, for example, has been shown to increase the signal detectability in the lacertid lizards Podarcis muralis , Specific site selection for secretion deposit may be another way of increasing signalling efficacy. Lizards of the species I. cyreni deposit their excrements at non-random sites (preferring high positioned rocks) to facilitate chemical or even visual detection by others (López, Aragón, & Martín, 1998 ...
1. The signals that animals use to communicate often differ considerably among species. Part of this variation in signal design may derive from differential natural selection on signal efficacy; the ability of the signal to travel efficiently through the environment and attract the receiver's attention. For the visual and acoustic modalities, the effect of the physical environment on signal efficacy is a well-studied selective force. Still, very little is known on its impact on the chemical signalling system.
2. Here, we take a broad, phylogenetic comparative approach to test for a relationship between animals’ signal chemistry and properties of their natural environment. Our study focused on lizards from the Lacertidae family.
3. We sampled 64 species across three continents and determined the lipophilic composition of their glandular signalling secretions by using gas chromatography-mass spectrometry (GC-MS). For each species, an array of environmental variables of high temporal and spatial resolution was obtained from climate databases.
4. Species varied considerably in the overall richness (number of constituents) of their secretions, as well as in the relative contribution of the major chemical compound classes. Signal richness and the relative contribution of the respective compounds exhibited little evidence of phylogenetic relatedness, suggesting that chemical signals may change very rapidly. While neither insularity nor substrate use affected chemical signal composition, we found a strong statistical relationship between the chemistry of the lizards’ secretions and aspects of the thermal and hydric environment they inhabit.
5. Species from ‘xeric’ milieus contained high proportions of stable fatty acid esters and high molecular weight alcohols in their glandular secretions, which likely increase the persistence of secretion scent-marks. In contrast, species inhabiting ‘mesic’ environments produced secretions of a high chemical richness comprising high levels of aldehydes and low molecular weight alcohols. This chemical mix probably creates a volatile-rich signal that can be used for long-distance airborne communication.
6. We argue that the observed variation in chemical signal design results from differential natural selection, optimizing signal efficacy under contrasting environmental conditions.
... Many neurophysiological studies have revealed that most lizards have well-developed ears (Wever, 1978;Manley, 1990Manley, , 2002. Nonetheless, most lizards except for geckos do not communicate intraspecifically with auditory signals (Marcellini, 1977;Lopez et al., 1998;Pianka and Vitt, 2003;Vercken and Clobert, 2008), and the functions of lizard hearing have not been well investigated. Several recent studies indicate that auditory cues are used for obtaining predator informa-tion either directly from acoustic sounds of predators (Cantwell and Forrest, 2013;Curlis et al., 2015) or indirectly through eavesdropping on heterospecific alarm calls. ...
Most lizards have well developed auditory abilities, while not actually vocalizing to any extent outside of geckos. However, except for geckos, function of hearing in lizards has not been well investigated. Recently, the ability to eavesdrop on the alarm calls of a syntopic avian species has been demonstrated in four species of lizards that belong to different families. This suggests that eavesdropping is a major function of hearing in lizards. To examine this possibility we tested the ability of heterospecific eavesdropping by a lizard that belongs to another family in an Ampijoroa forest of Madagascar, where two lizard species have been known to show this ability. We experimentally tested whether Zonosaurus laticaudatus, a gerrhosaurid lizard, has the ability to eavesdrop on the alarm calls of the Madagascar paradise flycatcher. In the experiment, we provided bait on the ground in front of free-ranging zonosaurs to induce their foraging activity and played back alarm calls or songs of the bird to them. The number of individuals that stopped for aging in response to the alarm calls was larger than that in response to the songs. Similarly, the number of individuals that fied in response to the alarm calls was larger than that in response to the songs. The zonosaurs stopped foraging for a longer time in response to the alarm calls than to the songs. These results demonstrate that Z. laticaudatus has the ability to eavesdrop on alarm calls of the Madagascar paradise flycatcher. It is suggested that heterospecific eavesdropping by non-vocal lizards is a common phenomenon, at least, in the Ampijoroa forest of Madagascar.
... Using tongue flicks (TFs), reptiles collect chemical samples from the environment and deliver them to the vomeronasal organ (Mason 1992;Cooper 1994;Schwenk 1995). Several studies across different lizard taxa have shown that chemical cues are involved in sexual recognition (López et al. 1998;Cooper and Pérez-Mellado 2002), informing different aspects such as age (López et al. 2003;Martín and López 2013), body size (Carazo et al. 2007;Huyghe et al. 2012), familiarity (Bull et al. 2000;Font and Desfilis 2002), health condition (López et al. 2006), and reproductive state (Head et al. 2005). ...
Chemical cues play an important role in sexual recognition in several lizard species. Here, we investigated whether the neotropical lizard, Liolaemus pacha (Iguania: Liolaemidae) can discriminate between chemical information obtained from males or females. In addition, we also considered the effect of season (reproductive vs. post-reproductive) and the sex of the tested individual. We experimentally tested scent discrimination, using a terrarium previously occupied by a male, a female, and an untreated terrarium as control as sources of different chemical scents. We counted the number of tongue flicks, a measure of chemical exploratory behavior, and the visual displays triggered by these scents for 10 min. Males performed significantly more tongue flicks when female scent was present than when male and control scents were present, indicating sexual recognition. However, females did not show a significant difference in those same conditions, indicating a lack of sexual recognition. For visual displays, males showed significantly higher rates to female and male scents than to control, whereas females did not show any difference. During the reproductive season, the number of tongue flicks and visual displays were higher than during the post-reproductive season. Our results suggest that for male L. pacha, chemical cues play an important role in mate recognition. We discuss the apparent lack of recognition in females. We suggest that the observed seasonal behavioral differences might be associated with physiological changes related mainly to reproduction.
... Chemical cues also play an important role in the production and perception of intraspecific sex pheromones for the coordination of reproductive behaviour of reptiles, like lizards (Halpern, 1992;Mason, 1992;Cooper, 1994;Martin and López, 2000;Martin and López, 2007), turtles (Munoz, 2004;Lewis et al., 2007) and snakes (Mason, 1992;Mason et al., 1998;LeMaster and Mason, 2003;Parker and Mason, 2009). Studies with different lizard species have shown pheromonal secretion of pre-cloacal and femoral glands (Cooper and Vitt, 1984;Alberts, 1990;López et al., 1998). The presence and relative concentrations of the glandular pheromone components vary between sexes and individuals (Alberts, 1990;).Mellado, 2002). ...
Sex pheromones in fish can be formed by the liver, the gonads and/or accessory sex organs, excreted through the urogenital efferent duct system, the faeces, the gills or the skin, and may play a role in the development of gonads, the attraction of reproductive partners, reproductive behaviour, sperm production or ovulation induction. In teleost fish, steroid glucuronides, steroid sulphates, free steroids and prostaglandines may function as sex pheromones, while in lampreys, bile acids are used as odourants for successful spawning. In amphibians, abdominal glands and fascial glands may secrete specific peptides or proteins as sex pheromones. In reptiles, the skin, pre-cloacal glands, femoral glands and seminal fluid are possible sources of sex pheromones, while in birds it is the uropygial gland which has this function. A mixture of specific methyl ketones has been indicated as a sex pheromone in snakes, whereas specific fatty acid diesters have been proved to serve as duck pheromones. Many classes of chemical compounds have been found to play or are thought to play a role as (sex) pheromones in mammals. They are produced by the urinary system, the digestive tract and/or all kind of glands. Olfactory signs may be secreted pulsatile in a species-specific mixture of components, of which the concentration and relative proportion is appropriate reproductive information and govern sexual behaviour. Besides olfactory signs, initiation and completion of adequate reproduction behaviour is additionally controlled by other sensory cues, like taste, visual, vibrational, tactile and/or auditory stimuli. Apart from the source, the nature and the role of (sex) pheromones in vertebrates, information is given on the perception of olfactory signals, the subsequent pathways that lead to electric signaling, and the transport of evoked nerve action potentials to and within the brain.
... Chemoreception is one of the main sensory systems for many animals, including a number of vertebrates, and chemical signals play an important role in communication and sexual selection in these animals [6][7][8]. For example, in lizards, chemical signals from femoral glands or faeces are very often used to scent-mark substrates, allowing to delimit territories or attract mates [9][10][11][12]. Chemical signals in scent-marks may provide information on sex, size, dominance, and even details of health condition of the signaller [7,[13][14][15][16]. ...
Sexual signals used in intraspecific communication are expected to evolve to maximize efficacy under a given climatic condition. Thus, chemical secretions of lizards might evolve in the evolutionary time to ensure that signals are perfectly tuned to local humidity and temperature conditions affecting their volatility and therefore their persistence and transmission through the environment. We tested experimentally whether interpopulational altitudinal differences in chemical composition of femoral gland secretions of male Iberian wall lizards (Podarcis hispanicus) have evolved to maximize efficacy of chemical signals in different environmental conditions. Chemical analyses first showed that the characteristics of chemical signals of male lizards differed between two populations inhabiting environments with different climatic conditions in spite of the fact that these two populations are closely related genetically. We also examined experimentally whether the temporal attenuation of the chemical stimuli depended on simulated climatic conditions. Thus, we used tongue-flick essays to test whether female lizards were able to detect male scent marks maintained under different conditions of temperature and humidity by chemosensory cues alone. Chemosensory tests showed that chemical signals of males had a lower efficacy (i.e. detectability and persistence) when temperature and dryness increase, but that these effects were more detrimental for signals of the highest elevation population, which occupies naturally colder and more humid environments. We suggest that the abiotic environment may cause a selective pressure on the form and expression of sexual chemical signals. Therefore, interpopulational differences in chemical profiles of femoral secretions of male P. hispanicus lizards may reflect adaptation to maximize the efficacy of the chemical signal in different climates.
... Compounds in feces seem to be useful for scent-marking and conspecifi c recognition. Scent from feces may provide information on familiarity, relatedness, or body size of the producer (Duvall et al. 1987;Carpenter and Duvall 1995;López et al. 1998;Bull et al. 1999aBull et al. ,b, 2001Aragón et al. 2000;Moreira et al. 2008;Wilgers and Horne 2009). Compounds from feces with properties of pheromones have not been identifi ed, but they are probably a combination of several lipids as, in the tree skink, Egernia striolata (Scincidae), they are contained in scat extracts made with organic solvents (dichloromethane); fractionation of the scats with different solvents (pentane and methanol) led to loss of the unique signals needed for individual recognition (Bull et al. 1999a). ...
... Moreover, cloacal secretions probably impregnate the surface of feces, which allows scent-marking and intraspecific communication using feces. Fecal pellets may function as composite visual and chemical signals, allowing conspecific and kin recognition in many species (Duvall et al., 1987;Carpenter and Duvall, 1995;López et al., 1998;Bull et al., 1999aBull et al., , 1999bBull et al., , 2000Bull et al., , 2001Aragón et al., 2000). ...
Many lizards have diverse glands that produce chemosignals used in intraspecific communication and that can have reproductive consequences. For example, information in chemosignals of male lizards can be used in intrasexual competition to identify and assess the fighting potential or dominance status of rival males either indirectly through territorial scent-marks or during agonistic encounters. Moreover, females of several lizard species "prefer" to establish or spend more time on areas scent marked by males with compounds signaling a better health or body condition or a higher genetic compatibility, which can have consequences for their mating success and inter-sexual selection processes. We review here recent studies that suggest that the information content of chemosignals of lizards may be reliable because several physiological and endocrine processes would regulate the proportions of chemical compounds available for gland secretions. Because chemosignals are produced by the organism or come from the diet, they should reflect physiological changes, such as different hormonal levels (e.g. testosterone or corticosterone) or different health states (e.g. parasitic infections, immune response), and reflect the quality of the diet of an individual. More importantly, some compounds that may function as chemosignals also have other important functions in the organism (e.g. as antioxidants or regulating the immune system), so there could be trade-offs between allocating these compounds to attending physiological needs or to produce costly sexual "chemical ornaments". All these factors may contribute to maintain chemosignals as condition-dependent sexual signals, which can inform conspecifics on the characteristics and state of the sender and allow to make behavioral decisions with reproductive consequences. To understand the evolution of chemical secretions of lizards as sexual signals and their relevance in reproduction, future studies should examine what information the signals are carrying, the physiological processes that can maintain the reliability of the message and how diverse behavioral responses to chemosignals may influence reproductive success.
... Moreover, cloacal secretions probably impregnate the surface of feces, which allows scent-marking and intraspecific communication using feces. Fecal pellets may function as composite visual and chemical signals, allowing conspecific and kin recognition in many species (Duvall et al., 1987;Carpenter and Duvall, 1995;López et al., 1998;Bull et al., 1999aBull et al., , 1999bBull et al., , 2000Bull et al., , 2001Aragón et al., 2000). ...
Many lizards have diverse glands that produce chemosignals used in intraspecific communication and that can have reproductive consequences. For example, information in chemosignals of male lizards can be used in intrasexual competition to identify and assess the fighting potential or dominance status of rival males either indirectly through territorial scent-marks or during agonistic encounters. Moreover, females of several lizard species “prefer” to establish or spend more time on areas scent marked by males with compounds signaling a better health or body condition or a higher genetic compatibility, which can have consequences for their mating success and inter-sexual selection processes. We review here recent studies that suggest that the information content of chemosignals of lizards may be reliable because several physiological and endocrine processes would regulate the proportions of chemical compounds available for gland secretions. Because chemosignals are produced by the organism or come from the diet, they should reflect physiological changes, such as different hormonal levels (e.g. testosterone or corticosterone) or different health states (e.g. parasitic infections, immune response), and reflect the quality of the diet of an individual. More importantly, some compounds that may function as chemosignals also have other important functions in the organism (e.g. as antioxidants or regulating the immune system), so there could be trade-offs between allocating these compounds to attending physiological needs or to produce costly sexual “chemical ornaments”. All these factors may contribute to maintain chemosignals as condition-dependent sexual signals, which can inform conspecifics on the characteristics and state of the sender and allow to make behavioral decisions with reproductive consequences. To understand the evolution of chemical secretions of lizards as sexual signals and their relevance in reproduction, future studies should examine what information the signals are carrying, the physiological processes that can maintain the reliability of the message and how diverse behavioral responses to chemosignals may influence reproductive success.
... This makes it unlikely that these highly reward-driven dogs will alter their capture probabilities as a function of the species, sex, reproductive status, age, sample concealment tendencies, or other characteristics of the subject. Scat collection by detection dogs also has advantages over researchers relying on visual detection because some subjects may deposit their scat more conspicuously than others (e.g., as a territorial mark; Ben-David et al. 1998;Lopez et al. 1998;Brashares and Arcese 1999). Sample acquisition is enhanced by the sensitive sense of smell in canids (3 ppm), which enables dogs to detect specific multiple (18+) odors (species) at distances over 0.25 mi (0.4 km) away (Syrotuck1972; Bryson 1991). ...
We report the development and application of a method using domestic dogs (Canis familiaris Linnaeus, 1758) to systematically locate wildlife scat over large remote areas. Detection dogs are chosen for their strong object orientation, high play drive, and willingness to strive for a reward. Dogs were trained to detect grizzly bear (Ursus arctos Linnaeus, 1758) and black bear (Ursus americanus Pallas, 1780) scats over a 5200-km2 area of the Yellowhead Ecosystem, Alberta, Canada. DNA from scat provided the species and (for grizzly bears only) sex and individual identities of the animal at each location. Concentrations of fecal cortisol and progesterone metabolites from these same grizzly bear scats provided indices of physiological stress and reproductive activity (in females), respectively. Black and grizzly bears were most concentrated in the northern portion of the multiuse study area, where food is most abundant yet poaching-related mortality appears to be heaviest. Physiologic stress was also lowest and female reproductive activity correspondingly highest for grizzly bears in the north. The scat-based distributions corresponded to concurrently collected hair-snag data in 1999 and global positioning system radiotelemetry data (of grizzly bears) in 1999 and 2001. Results suggest that the scat dog detection methodology provides a promising tool for addressing a variety of management and research questions in the wildlife sciences.
... The general perception of many lizards, including agamids, is that they rely heavily on visual cues in their assessment of rivals and partners. However, even in highly visual species, there is strong sexual dimorphism in femoral pores and other odour glands, and males mark their territory with scent or deposit faecal pellets at strategic places (Mason 1992;López et al. 1998;Aragón et al. 2000). The role of scent as an important cue in lizard mating strategies may therefore have been overlooked, especially since scent may confer detailed information on genetic compatibility, which is of particular importance in mate choice (Tregenza and Wedell 2000;Penn 2002). ...
Female choice for genetic complementarity or unrelated males occurs in several vertebrate taxa, but only a few species per higher-order taxon have so far been studied. This is particularly the case in reptiles, where female choice traditionally has been considered to be less important than in most other vertebrates. Many species of reptiles use scent marking in relation to territory use and, consequently, females may use this information to avoid settling on genetically incompatible (e.g. related) males’ territories. We tested the response of female Australian dragon lizards, Ctenophorus pictus, to pheromones from closely related and unrelated males. Contrary to predictions, females did not prefer to associate with scent from unrelated males. The reason for the lack of differential response to related and unrelated males could be explained by weak selection against inbreeding, high dependence on visual cues, female control over copulation, or post-copulatory female choice. Alternative hypotheses are discussed in relation to the biology of the species and lizard biology in general.
... Chemoreception is one of the main sensory systems used by many animals, including many vertebrates, and chemical signals (pheromones) play an important role in communication and sexual selection (Wyatt 2003;M€ uller-Schwarze 2006;Mason & Parker 2010). In terrestrial vertebrates, pheromones are very often incorporated into faeces, urine or other scent marks left on the substrate with the purpose of marking territories boundaries or attracting mates (L opez, Arag on & Martín 1998;Brennan & Kendrick 2006;Martins et al. 2006). For example, many lizards produce chemical secretions with pheromonal activity (Mason 1992). ...
An almost neglected aspect of climate change is its effects on sensory ecology and sexual signals of animals. Signals used in intraspecific communication are expected to evolve to maximize efficacy under a given climatic condition, but it is unlikely that quick changes in environmental conditions could be compensated by similarly quick evolutionary changes in the design of signals. We predict that global warming will lead to a loss of efficacy of some sexual signals, with important consequences for sexual selection.
We examined experimentally the effects of global warming on the efficacy of chemical signals of a mountain lizard ( Iberolacerta cyreni ).
We first showed how environmental temperatures in the study area during the mating season of lizards have actually increased in the last years. Then, we tested whether female lizards were able to detect by chemosensory cues the males’ scent marks (i.e. femoral secretions) that were experimentally maintained under current and predicted future temperature conditions.
Results showed that the efficacy (i.e. detectability and persistence) of scent marks is lower at high temperature. Moreover, we showed that scent‐marked substrates maintained under high temperatures were not selected by females, in contrast to the selection of areas scent marked by males, when these substrates were maintained under normal temperatures.
Our study suggests that climate warming could lead to negative changes in the efficacy of sexual signals with potential consequences for the sexual selection and conservation of threatened lizard species.
... Jaeger et al. 1986;Simons et al. 1994), reptiles (e.g. Carpenter & Duvall 1995;Ló pez et al. 1998) and mammals (Gorman 1984;Brown & Macdonald 1985). Because chemical signals persist in the environment after being emitted (Alberts 1992), conspecifics can use scent marks to obtain information about the scent donor even in its absence (e.g. ...
The ‘scent-matching’ hypothesis predicts that competitors could identify resource holders by investigating scent marks from a given area and matching these with the owner's odour when they meet. Previous studies on small rodents have supported the use of scent matching among males with mutually exclusive ranges. We designed an experiment to evaluate the potential role of scent matching in the snow vole, a species in which males have largely overlapping ranges but individually use specific locations within shared areas. Initial exploration of enclosures containing a choice between a scent-marked and an unmarked area established that males were more attracted to recently occupied areas. During a subsequent social encounter with either the donor of the scent marks present in the enclosure (matching opponent) or another male (nonmatching opponent), males were less aggressive towards matching than nonmatching opponents. Furthermore, during exploration of enclosures after encounters, males spent significantly less time at the scent-marked side after meeting a matching male but not after meeting another male. These results suggest that male snow voles may use scent matching to identify potential opponents and to respond differentially to occupied areas. By modifying their behaviour after assessing the identity of their opponents, males may be able to minimize current and prospective costly encounters with resource holders. Our findings show that the mechanism of scent matching is also compatible with spatial systems in which competing conspecifics possess overlapping ranges.
... Faeces is one of the major media by which metabolic products are eliminated from the animal and, therefore, it is not surprising that faeces can potentially convey much information about the internal physiology of the animal to the external world and thus, provide a source of chemosignals in many species. It is a point to note that faeces is considered to be a potent source of chemical signals in rats (Lee and Moltz, 1985), pigs (Morrow-Tesch and McGlone, 1990), lizards (Lopez et al., 1998) and blackbucks (Rajagopal et al., 2011) which all support the present opinion. ...
Chemo-signals are among the reliable non-invasive methods for estrus detection in mammals. Water buffalo is a silent heat animal and, hence, there is search for chemo-signals which would be effective non-invasive indicators of estrus state. We analyzed the faecal chemical cues during the estrous cycle in buffalo and to find the estrus-specific faecal volatile compounds adopting bull behavior assay. The faecal samples were collected at three phases of the estrous cycle (i.e., proestrus, estrus and postestrus) and subjected to gas chromatography-mass spectrometry analyses. We found 27 volatile compounds in the faeces of buffaloes, of which 4-methyl phenol (4mp) and trans-verbenol (tv) were found only in estrus faeces. The faecal samples of estrus buffaloes and the estrus-specific compound(s) (4mp+tv) at three different concentrations were tested for behavioral responses (flehmen and mounting behavior) in the bull. The bulls exhibited repeated flehmen when exposed to a combination of the two compounds (i.e., 4mp+tv) as compared to the individual compounds or raw faecal sample collected from buffalo when in estrus (P<0.05). However, higher number of mounting behavior was recorded when bulls were exposed to 4mp followed by a combination of the two compounds (4mp+tv) and trans-verbenol (P<0.05), in that order. By contrast, less number of mounting behavior was exhibited by bulls when exposed to the control sample (i.e., Hexadecanoic acid) (P<0.05). As inferred from the bull behavior assay, the present study suggests that the two compounds, 4 methyl phenol and trans-verbenol would be reliable indicators of estrus in buffaloes.
... This information may be used by females to assess the competitive ability of the top-scent males, which, based on this trait alone, may be the preferred partners (Johnston et al., 1997a,b). Other animals, such as lizards, might not actively over-mark, but, in some species, the high spatial overlapping of home ranges would similarly lead to over-marks, especially if males tend to mark on specific preferred places such as on the top of high rocks or other preferred basking places (López et al., 1998;Martins et al., 2006). Also, territorial lizards preferentially visit areas in their territories recently marked by other lizards, which may result in over-marking (Carazo et al., 2008). ...
Scent-marked substrates may inform conspecifics on the characteristics of territorial males. Scent-marks of male Carpetan rock lizards (Iberolacerta cyreni) affect space use of females, which by selecting an area may increase the probability of mating with the male that has scent-marked that area. However, males do not hold exclusive territories, and scent-marks of different individual males are often together. This may provide complex information from multiple sources on the social structure. Here, we examined female preference in response to scent marks of various males and combinations in a laboratory experiment. Females preferred areas scent-marked by territorial old males against those scent-marked by young satellite-sneaker males. This reflected the known preference of females for mating with old males. In a second experiment, females preferred areas scent-marked by two males to areas of similar size marked by a single male. This may increase the probability of obtaining multiple copulations with different males, which may favour sperm competition and cryptic female choice, or may be a way to avoid infertile males. Finally, when we experimentally over-marked the scent-marks of an old male with scent-marks of a young male, females did not avoid, nor prefer, the over-marked area, suggesting that the quality of the old male may override the presence of a satellite male. We suggest that, irrespective of the causes underlying why a female selects a scent-marked area, this strategy may affect her reproductive success, which may have the same evolutionary consequences that "direct" mate choice decisions of other animals.
... Organisms leave chemical traces of themselves behind as they pass through the environment. Sometimes these chemicals carry out vital functions; for example, pheromones may attract mates (Pearce & Hughes 1987; Shelly 2004 ) and ⁄ or demarcate territorial boundaries (Johnson 1973; Lopez et al. 1998; Hurst & Beynon 2004 ). Other chemosensory information is deposited on the substrate as a result of unavoidable metabolic and excretory processes, with no adaptive function (Clark 2004). ...
In lizards and snakes, foraging mode (active vs. ambush) is highly correlated with the ability to detect prey chemical cues, and the way in which such cues are utilized. Ambush-foraging lizards tend not to recognize prey scent, whereas active foragers do. Prey scent often elicits strikes in actively-foraging snakes, while ambushers use it to select profitable foraging sites. We tested the influence of foraging ecology on the evolution of squamate chemoreception by gauging the response of Burton’s legless lizard (Lialis burtonis Gray, Pygopodidae) to prey chemical cues. Lialis burtonis is the ecological equivalent of an ambush-foraging snake, feeding at infrequent intervals on relatively large prey, which are swallowed whole. Captive L. burtonis did not respond to prey odour in any manner: prey chemical cues did not elicit elevated tongue-flick rates or feeding strikes, nor were they utilized in the selection of ambush sites. Like other ambushing lizards, L. burtonis appears to be a visually oriented predator. In contrast, an active forager in the same family, the common scaly-foot (Pygopus lepidopodus), did tongue-flick in response to odours of its preferred prey. These results extend the correlation between lizard foraging mode and chemosensory abilities to a heretofore-unstudied family, the Pygopodidae.
... These kinds of studies are scarce in lacertid lizards (Pilorge et al., 1983; Barbault and Mou, 1988; Bauwens and Díaz-Uriarte, 1997; Galán, 1997; Bauwens, 1999; Castilla and Bauwens, 2000a, b). Recently, the Iberian rock lizard, Lacerta monticola, became a model organism for studies of behaviour (Martín and López, 1999Martín and López, , 2000Martín and López, , 2001), the effect of caudal autotomy ( Salvador, 1995, 1997), and chemical communication (López et al., 1998; Aragón et al., 2000). However, these studies address populations inhabiting the high mountain areas of central Spain (Sierra de Guadarrama) and that belong to the clearly differentiated taxon L. m. cyreni (see below). ...
We studied the reproductive ecology of a population of the lacertid lizard Lacerta monticola at a lowland location in A Coruña (NW Spain) from 1997 to 2002. The timing of the reproductive cycle was examined based on mark-recapture records of individual lizards in the eld. The characteristics of the eggs and hatchlings were obtained from clutches laid in the laboratory by pregnant females that were temporarily removed from the study area. Our results indicate that mating took place between late March and July. The smallest female with signs of sexual maturity had a snout-vent length (SVL) of 52.4 mm and the smallest male was 50.7 mm. Sexual maturity was attained at the age of 2 years by 41% of the individuals, while the remaining 59% of the lizards matured at the age of 3 years. The laying period occurred between June and the beginning of August considering all years. About 61% of the reproductive females produced a single clutch annually, while 39% of the females produced two clutches per year. Females that produced two clutches were generally larger (average SVL D 70.9 mm) than those that laid a single annual clutch (average SVL D 62.6 mm). The mean clutch size was 6.4 eggs (range 4-9). Both clutch size and clutch mass increased signi cantly with female SVL. The mean egg mass in a clutch decreased signii cantly with clutch size. Hatching occurred between August and September. Hatching success in the laboratory was 71.7%. The mean SVL was higher in female hatchlings than in males.
... and even species assignation is doubtful except if lizards are captured and forced to defecate; pellets are not randomly deposited (i.e., in the most prominent sites and by the dominant individuals, López et al., 1998) and prey composition is seriously biased (see below ). Finally, gut content examination is the most common method. ...
Lacertids are the dominant group of lizards throughout the Mediterranean Basin. Their role in food web transfer of matter and energy from arthropods and other small invertebrates to birds and mammals constitutes a major function within Mediterranean ecosystems. For many years, prey consumption by lacertids was thought to be almost indiscriminate, not much more than a by-product of habitat use. However, increasing evidence does not support this passive view. Analyses of prey availability have revealed active prey selection/avoidance in several species. Others show an internal tendency (i.e., historical constraints) to consume specific animal items (ants, clumped prey) or plant matter (seeds, nectar, pollen, leaves). Behavioural experiments showed that lacertids not only identify different prey types by both visual and chemical cues but also modify their feeding behaviour integrating past experiences. Furthermore, size, sex, reproductive state, body condition, tail loss and probably other lizard features are relevant for feeding ecology. However, less attention has been devoted to abiotic factors such as temperature and humidity. More experimental studies of the influences of competitors, predators and parasites on diet are needed. Even though it is controversial, optimal foraging theory provides a conceptual background for future studies. The evolutionary history of the various lacertid lineages, which constrains their morphology and physiology and eventually produces exaptative traits, is to be considered as well. Finally, methodology in field sampling, lab work and statistical analysis needs to be developed. Recommendations are given as to when and where to sample, which compartment should be analysed, which is the appropriate sample size, how to assess trophic availability, which statistical descriptors should be used and how they should be compared.
Contests are an important aspect of the lives of diverse animals, from sea anemones competing for space on a rocky shore to fallow deer stags contending for access to females. Why do animals fight? What determines when fights stop and which contestant wins? Addressing fundamental questions on contest behaviour, this volume presents theoretical and empirical perspectives across a range of species. The historical development of contest research, the evolutionary theory of both dyadic and multiparty contests, and approaches to experimental design and data analysis are discussed in the first chapters. This is followed by reviews of research in key animal taxa, from the use of aerial displays and assessment rules in butterflies and the developmental biology of weapons in beetles, through to interstate warfare in humans. The final chapter considers future directions and applications of contest research, making this a comprehensive resource for both graduate students and researchers in the field.
Animals exhibit considerable and consistent among-individual variation in cognitive abilities, even within a population. Recent studies have attempted to address this variation using insights from the field of animal personality. Generally, it is predicted that animals with “faster” personalities (bolder, explorative, and neophilic) should exhibit faster but less flexible learning. However, the empirical evidence for a link between cognitive style and personality is mixed. One possible reason for such conflicting results may be that personality–cognition covariance changes along ecological conditions, a hypothesis that has rarely been investigated so far. In this study, we tested the effect of habitat complexity on multiple aspects of animal personality and cognition, and how this influenced their relationship, in five populations of the Aegean wall lizard (Podarcis erhardii). Overall, lizards from both habitat types did not differ in average levels of personality or cognition, with the exception that lizards from more complex habitats performed better on a spatial learning task. Nevertheless, we found an intricate interplay between ecology, cognition, and personality, as behavioral associations were often habitat- but also year-dependent. In general, behavioral covariance was either independent of habitat, or found exclusively in the simple, open environments. Our results highlight that valuable insights may be gained by taking ecological variation into account while studying the link between personality and cognition.
Pheromones, a mix of proteins and lipids, are involved in lizards' conspecific recognition. In our study, we specifically address whether fecal lipids are involved in conspecific recognition of the Weeping Lizard, Liolaemus chiliensis. The feces of each sex were dissolved in n-hexane to isolate their lipidic fraction. We then exposed individuals of both sexes of L. chiliensis to the lipidic fractions of each sex and a control (n-hexane), recording their responses. Lizards of both sexes were more active when exposed to the lipids from male than from female feces or from the control, suggesting that the lipidic fraction of male feces conveys some information for conspecific recognition. There was, however, no further evidence of recognition, and herein we offer possible explanations for this low responsiveness to the fecal lipidic fractions.
Chemical signals are essential for intersexual communication in many animals, including lizards. While faeces have been suggested to contain socially relevant chemical stimuli, epidermal gland secretions are generally believed to be the leading source of chemosignals involved in lizard communication. Early research has shown that sex hormones affect epidermal gland activity, with androgens stimulating gland/pore size and/or gland productivity. However, the functional significance of hormone-induced glandular activity in lizard chemical communication remains unclear. In this study, we manipulated testosterone (T) concentrations in male Podarcis muralis lizards. While T-supplementation did not change pore size, it did increase secretion production substantially. Chemosensory tests showed that female conspecifics tongue-flick at a higher rate and more quickly towards the secretion of males with experimentally increased T levels than towards the secretion of control males, suggesting that females can discriminate between males with dissimilar T levels based on chemical cues of secretion alone. Based on the scent of faeces, however, females were unable to discriminate between males with differential T levels. Also, females reacted more quickly when offered larger amounts of secretion – irrespective of whether secretions were obtained from control or T-increased males. This result indicates that secretion quantity affects chemosignal detectability in Podarcis muralis.
Although many lizard species detect and respond to conspecific chemical cues, variation in this ability among populations of the same species from different habitat types is less well understood. We compared chemoreceptive behaviors and head-bobs in response to conspecific chemical cues by Ornate Tree Lizards (Urosaurus ornatus) between populations from an upland forested habitat and a lowland desert habitat. Under this experimental design, U. ornatus from different habitats performed chemoreceptive behaviors and head-bobs at similar rates. Rate of chemoreceptive behaviors and head-bobs in response to chemical cues deposited by same- and opposite-sex conspecifics was higher than that of cues deposited by the subject in their home tank, demonstrating that U. ornatus has the ability to detect cues from conspecifics. Head-bob rate was also higher in same- and opposite-sex tanks compared to home tanks, demonstrating that chemical cues alter the rate of a social display behavior. Urosaurus ornatus exhibited chemosensory behavior at rates similar to rates reported for this species and lower than those reported for other phrynosomatid lizards, suggesting a lower reliance on chemical cues in social interactions.
Contests are an important aspect of the lives of diverse animals, from sea anemones competing for space on a rocky shore to fallow deer stags contending for access to females. Why do animals fight? What determines when fights stop and which contestant wins? Addressing fundamental questions on contest behaviour, this volume presents theoretical and empirical perspectives across a range of species. The historical development of contest research, the evolutionary theory of both dyadic and multiparty contests, and approaches to experimental design and data analysis are discussed in the first chapters. This is followed by reviews of research in key animal taxa, from the use of aerial displays and assessment rules in butterflies and the developmental biology of weapons in beetles, through to interstate warfare in humans. The final chapter considers future directions and applications of contest research, making this a comprehensive resource for both graduate students and researchers in the field.
The study of natural variation has long fascinated evolutionary biologists and attempts to
account for it were major contributors to the formulations of Darwin´s idea of evolution. The
main goal of this thesis is to study the factors that shape phenotypic variation in the Iberian
wall lizard species complex (P. hispanicus). We specifically focused on two recently
described species within this species complex, P. guadarramae and P. liolepis. We first
performed a common garden experiment (Chapter I) to examine differences in reproductive
investment and the underlying basis of the altitudinally divergent phenotypes of two P.
guadarramae populations located along an altitudinal gradient with contrasted climatic
conditions. We also performed a reciprocal transplant experiment (Chapter II) aiming to
determine the influence of proximate effects of local environmental conditions on hatchling
growth in lizards from the two populations commented above. We also measured food
availability in both sites to determine the relationship between ecosystem productivity and
growth. In Chapter III, our main goal was to disentangle the factors that shape variation in
conspicuous colourful tails and dorsal pattern morphs and its relationship with escape
behaviour in P. guadarramae juvenile lizards. In Chapter IV, we tested the hypothesis that
selection acts differentially among P. hispanicus female morphs (reticulated-blotched vs.
striped) to create alternative morph-specific phenotypic optima at different levels, by testing
whether morphs differ in several fitness proxies. For this, we measured morphology, dorsal
coloration, reproductive investment and immune response of adult female morphs, and
morphology, growth, and dorsal coloration of their offspring. In Chapter V we examined
altitudinal variation in morphology, and ventral and dorsal coloration populations in adult P.
liolepis. In Chapter VI, we examined the efficacy (i.e., persistence and detectability) of
sexual chemical signals of males (i.e. femoral gland secretions) at different temperatures and
316
humidity levels to test the hypothesis that chemical signals of male lizards have evolved to
maximize efficacy of chemical signals in different environmental conditions (highland vs
lowland).
The common garden experiment (Chapter I) shows that altitudinally divergent adult
body sizes of P. hispanicus lizards are not driven by size at hatching, which is not contributed
to by egg size, nor intrinsic post-hatching growth rates associated with the environmental
conditions experienced in the experiment. Thus, adult phenotypic differences are the result of
a plastic response which was latter confirmed by a reciprocal transplant experiment (Chapter
II) where the growing environment determines growth rates, independently of population of
origin. The drivers of growth rate differences are likely between-sites differences in food
availability and quality.
We also provide evidence for the existence of sexual and intermorph dimorphism in
tail ultraviolet colour reflectance of hatchling P. hispanicus lizards (Chapter III). Hatchling
reticulated-blotched females have more UV reflectance in their tails than striped females and
reticulated-blotched males, while striped females have intermediate UV reflectance and males
the lowest UV reflectance. In addition, we identify sex/dorsal morph, body size and
brightness as predictors of different aspects of escape behaviour, and two alternative escape
strategies between striped and reticulated-blotched hatchlings that are probably dependent on
dorsal morph differences, independently of sex. Reticulated-blotched individuals run faster
and spend less time paused than striped females, which might reflect an escape behaviour
strategy based on endurance in striped females. Larger hatchlings run longer distances and tail
wave less than smaller hatchlings. In addition, lowland males display tail waving as a ‘last
resort’ antipredator strategy that may be related to fatigue. Moreover, hatchlings with brighter
tails take fewer pauses between sprint bursts than those with duller tails, adopting a shier
behaviour that may minimize predation risk during flight episodes. Hence, hatchling
317
antipredatory behaviour is influenced by the interactions between dorsal patterns, size and tail
conspicuousness.
The two melanin-based dorsal morphs of female P. hispanicus have contrasted
reproductive strategies (Chapter IV). Hatchlings born from reticulated-blotched females are
larger and heavier than those born from striped ones, which suggest the role of maternal
effects mediating offspring phenotype differences between the two morphs. Female dorsal
morphs and age classes differ in terms of melanin based, and brownish dorsal coloration.
Adult striped and hatchling females are darker than reticulated-blotched adult females and
hatchlings, respectively. Moreover, adult female morphs have different morphology as
reticulated-blotched females have deeper heads and longer femora than striped ones. Our
results also suggest that this female-limited polymorphism is not maintained by selective
pressures related to immune response. We also neglect the existence of a relationship between
melanin-based coloration and hatchling growth and adult immune response. Finally, immune
response do not differ between adult female dorsal morphs.
Highland P. liolepis lizards are larger, stockier and have more femoral pores and a
darker dorsal coloration than lowland ones (Chapter V). Thus, highland and lowland P.
liolepis follow the same pattern of variation observed in other species within the P. hispanicus
species complex. Dorsal and ventral coloration fluctuate seasonally and between populations.
Brightness of ventral and dorsal coloration are higher in lowland than in highland lizards in
spring whereas the reversed trend is found in summer. In addition, lizards in summer had
more throat bluish reflectance than in spring and is also males had more bluish reflectance for
all body regions except for the throat. We determine the existence of an anterior-posterior
gradient of red ventral coloration, with the highest values in the throat. In addition, summer
lizards had more brownish coloration than spring ones whereas spring lizards had more
greenish coloration than summer ones.
318
Finally, the chemical secretions of male P. hispanicus lizards differ between
two populations (Chapter VI). Lower elevation males have higher proportions of cholesterol
and fatty acids, but lower proportions of alcohols than higher elevation males. Moreover,
chemosensory tests with female lizards show that chemical signals of males have a lower
efficacy when time since deposition, temperature and dryness increase. These effects are more
detrimental in the higher elevation population that occupies naturally colder and more humid
environments. Therefore, interpopulational differences in chemical profiles of femoral
secretions of male P. hispanicus lizards might reflect adaptation to maximize the efficacy of
the chemical signal in different climates
Assessment of the fighting ability of potential opponents is an essential skill to minimize the costs of agonistic interactions between males. Previous research showed that chemical cues released in the water by male turtles may convey information about body size, which is important for intrasexual competition. However, the mechanistic basis of such chemical signaling of body size remains poorly understood. Here, we aimed to experimentally examine whether the release of chemosignals is quantitatively or qualitatively dependent on body size in male Spanish terrapins Mauremys leprosa. We compared the time that turtles spent in a pool with clean water versus water containing chemical stimuli of conspecific males of different body sizes at two different concentrations ("diluted" or "undiluted"). Male terrapins avoided water with chemicals secreted by relatively larger males when these chemicals were undiluted, but not after the chemical stimuli were diluted. In contrast, male terrapins did not avoid chemicals of relatively smaller males in any treatment. Thus, male M. leprosa may assess the size of their rivals on the basis of the concentration or the amounts of their chemical cues released into the water and consequently avoid occupying these ponds with higher concentrations of chemicals. This study gives important hints about the mechanism of chemical signaling in freshwater turtles and demonstrates that male turtles may discriminate different concentrations of chemosignals of conspecifics and modify their behavior accordingly. Likewise, our results support the notion that relative body size is a key factor during male interactions in Spanish terrapins.
Although many lizard species detect and respond to conspecific chemical cues, variation in this ability among populations of the same species from different habitat types is less well understood. We compared chemoreceptive behaviors and head-bobs in response to conspecific chemical cues by Ornate Tree Lizards (Urosaurus ornatus) between populations from an upland forested habitat and a lowland desert habitat. Under this experimental design, U. ornatus from different habitats performed chemoreceptive behaviors and head-bobs at similar rates. Rate of chemoreceptive behaviors and head-bobs in response to chemical cues deposited by same- and opposite-sex conspecifics was higher than that of cues deposited by the subject in their home tank, demonstrating that U. ornatus has the ability to detect cues from conspecifics. Head-bob rate was also higher in same- and opposite-sex tanks compared to home tanks, demonstrating that chemical cues alter the rate of a social display behavior. Urosaurus ornatus exhibited chemosensory behavior at rates similar to rates reported for this species and lower than those reported for other phrynosomatid lizards, suggesting a lower reliance on chemical cues in social interactions.
Contests are an important aspect of the lives of diverse animals, from sea anemones competing for space on a rocky shore to fallow deer stags contending for access to females. Why do animals fight? What determines when fights stop and which contestant wins? Addressing fundamental questions on contest behaviour, this volume presents theoretical and empirical perspectives across a range of species. The historical development of contest research, the evolutionary theory of both dyadic and multiparty contests, and approaches to experimental design and data analysis are discussed in the first chapters. This is followed by reviews of research in key animal taxa, from the use of aerial displays and assessment rules in butterflies and the developmental biology of weapons in beetles, through to interstate warfare in humans. The final chapter considers future directions and applications of contest research, making this a comprehensive resource for both graduate students and researchers in the field.
Colour variation in females is expected to play a role in intra-specific communication by signalling for traits that are socially relevant. However, in some cases, the information carried by colour signals is not sufficient and other cues may be used by conspecifics, such as chemosensory cues. In the common lizard, ventral coloration of females can be classified as yellow, orange or mixed. These ventral colours have been shown to predict the outcome of dyad encounters in an experimental context. However, there was no evidence that females really used the colour signal to assess the competitive ability and the social strategy of their opponent. In lacertids, chemical signals are often implicated in intraspecific communication, and could be used by females to acquire information useful for social interactions. We performed dyad encounters in which the ventral colour of the opponent was either visible or not, and studied the response of the focal female. We found that females used the colour of their opponent as a signal to adjust their own behaviour, but they also seem to be able to use other complementary cues, most probably behavioural cues. Females of different colours also differed in their ability to respond to a novel situation, which suggests colour-based differences in the plasticity of social behaviour.
Adult males react differently to neighbours and non-neighbours, implying individual recognition of neighbouring territory holders. -P.J.Jarvis
In studies of squamate responses to prey chemicals presented on cotton-tipped applicators, investigators typically record several responses, each of which gives only part of the overall picture. The tongue-flick/attack score (TFAS) is a widely used composite measure of response strength that accounts for attack, its latency, and number of tongue-flicks. We present data and analyses on these variables and investigate the utility of several other possible response variables. It is concluded, for both practical and theoretical reasons, that TFAS and two modifications of it are the best measures of response strength. Uses and statistical analyses of TFAS and variables derived from it are discussed. It is recommended that information on tongue-flick rate, number of individuals attacking, and latency to attack be presented.
By themselves the scent marks in the territories of male mammals can provide only general
information about the signaller (such as sex and androgen levels). Whether intruders use
this information and avoid the area, or only leave after obtaining more information about
the signaller should depend on the benefits of intruding (using the defended resources) less
the costs (risk of detection, and of damage if attacked). Costs are partly dependent on the
intruder's competitive ability, and, assuming a link between competitive ability and body
size, we tested the prediction that male house mice of low body weight should be more
likely to avoid scent-marked areas than males of high body weight. A modified Y-maze
was used to examine the males' initial decision about whether or not to enter an artificially
scent-marked tunnel. Subjects and donors of urine for the artificial scent marks were kept
in isolation before testing, a state that promotes high androgen levels. Subjects had never
met the donors and so the effect of previous contests, including any with the signaller,
could be excluded. As predicted, light males avoided the artificially scent-marked area,
both in a sample of young (88- 108 days) and older (140- 160 days) adult mice. Heavy mice
were attracted to the artificially marked substrate, possibly because, to males that are less
likely to be damaged in contests with the signaller, marks indicate a resource that is worth
defending.
Previous work has shown that dominant male mice, Mus musculus, are usually attracted to scent-marked areas while subordinates avoid them. In this study, the responses of subordinates were highly variable, and the idea that the probability of intruding onto a scent-marked substrate depends on their competitive ability was tested. Subjects were kept in dominant/subordinate pairs of males and tested with scent marks of an unfamiliar male. Subordinates who were large in relation to their dominant partners were more likely to choose a scent-marked substrate in a Y-maze choice against a blank substrate; relatively small subordinates were more likely to avoid scent marks. Males that chose scent marks also tended (P=0.08) to be more often involved in escalated contests with their dominant partners. Body size is known to affect the outcome of fights between strangers and these results could be explained if relatively large subordinates are (1) more likely to be able to defeat the resident of a scent-marked area (and thus benefit from its resources) and (2) if large subordinates pose a greater threat of a dominance reversal to their dominant partners than would a relatively small subordinate.
The authors analyzed the ability of male amphisbaenian (
Blanus cinereus) to distinguish self-produced chemical cues from those of other conspecific males. In experiments using randomized block designs, males were presented cotton swabs bearing male stimuli, their own stimuli, and deionized water in counterbalanced sequence.
Blanus cinereus directed significantly more tongue flicks at swabs treated with chemical stimuli from precloacal pores and dorsal trunk skin from conspecific males than to their own stimuli from the same sites. Response to their own precloacal pore stimuli did not differ significantly from that to deionized water, but males tongue-flicked their own dorsal trunk skin stimuli more than deionized water. More male amphisbaenians bit swabs bearing the male conspecific stimuli than the other 2 stimuli. These results suggest that males detect their own chemical stimuli from dorsal trunk skin and discriminate between their own stimuli and those of other males. Communication by chemosensory cues in amphisbaenians is discussed in relation to fossoriality. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
This paper presents an observational and experimental study of the basking behaviour and heat exchange rate of the montane lizard Lacerta monticola. The results obtained by these procedures were coupled in order to understand behavioural mechanims promoting effective thermoregulation at high altitudes. Heating rate was higher when body size was smaller, and substrate temperature and sun rays incidence angle were higher. The lizards cooled faster when body size and substrate temperature were lower, and when the body temperature of the lizard going into shadow was higher. Time exposed to sun and mean duration of basking periods were longer early in the morning, while bask frequency increased through the morning. Our results suggest that time devoted to basking is mainly obtained by regulating bask duration. Lizards obtained the necessary time for heating by means of long basking periods. Mean travel distance per minute and distance to the nearest refuge increased from early morning to midday. These behavioural variables were tightly correlated with the expected heating rate of individuals. Body size affects thermoregulatory behaviour as well as locomotor activity. Juvenile lizards, with small body mass and high surface-to-volume ratios, were subjected to faster heating and cooling rates, basked more frequently than adults (but during shorter periods), and devoted more time to locomotion than adults. The thermoregulatory behaviour of L. monticola is the result of the combination of shuttling heliothermy by basking and the exploitation of thermal opportunities offered by patches in shade through thermal exchange with the substrate.
Many lizards autotomize their tails to escape when grasped by a predator. It is hypothesized that tail loss causes a reduction in social status, thereby potentially lowering their reproductive success. We experimentally induced tail loss in Lacerta monticola in a semi-natural enclosure, and show that tail loss reduced social status and mating access in males. Tailless males increased body mass more rapidly than tailed dominant males, probably due to lower aggression costs. Also, tailless females were courted less and copulated less than tailed females, supporting the hypothesis that tail loss decreases reproduction potential.
1 The olfactory system of vertebrates.- 1.1 Anatomy.- 1.2 Odorant characteristics.- 1.3 Function of the external nares and related structures.- 1.4 Evolutionary trends.- 1.5 Summary.- 2 Sources and chemistry of vertebrate scent.- 2.1 The sites of odour production.- 2.2 Chemical composition of odorants.- 2.3 Threshold levels of perception.- 3 Detection of food.- 3.1 Responses of young to food odours.- 3.2 The detection of plant food by odorous cues.- 3.3 The detection of animal food by odorous cues.- 3.4 Scavengers.- 3.5 Quasi-parasites.- 3.6 Summary.- 4 Reproductive processes.- 4.1 Sex attraction and recognition the advertisement of sexual status.- 4.2 Detection and induction of oestrus, ovulation and lordosis.- 4.3 Courtship, mating and related behaviours.- 4.4 Pregnancy.- 4.5 Parental behaviour imprinting.- 4.6 Growth physical and psychosexual development.- 4.7 Summary and conclusions.- 5 Odour discrimination and species isolation.- 5.1 Individual odour.- 5.2 Family, population and racial odours.- 5.3 Species odours and sexual isolation.- 5.4 Summary and conclusions.- 6 Dispersion and social integration.- 6.1 Intraspecific aggression.- 6.2 The social hierarchy.- 6.3 Territoriality.- 6.4 Correlation between aggression-motivated behaviour and scent deposition.- 6.5 Summary and conclusions.- 7 Alarm and defence.- 7.1 Detection of the predator.- 7.2 Transmission of alarm or warning signals.- 7.3 Active defence.- 7.4 Protection from intraspecific attack.- 7.5 Summary.- 8 Olfactory navigation and orientation.- 8.1 Olfactory navigation.- 8.2 Homing orientation.- 8.3 Summary.- 9 Applications of researches into olfactory biology.- 9.1 Pest repellents and attractants.- 9.2 Animal husbandry.- 9.3 Miscellaneous applications.- References.- Taxonomie index.
The existence of territoriality in salamanders was firmly established only about seven or eight years ago. Before that time, there was some evidence that individuals of several species engaged in intraspecific conflicts and that non-random distributions of individuals occurred. However, so little was known about the behavior of salamanders (other than courtship and homing) that it was impossible to piece together a comprehensive picture of spatial interactions. Today there is still less information about territorial behavior of salamanders than there is about almost any other group of vertebrates, and less than for many groups of invertebrates. The evolution, function, mechanisms, and ontogeny of territoriality are only vaguely understood. What knowledge does exist is confined to the salamander family Plethodontidae (the lungless salamanders), and within this family, only seven or eight species have been critically studied. These species are distributed among the three genera Aneides, Desmognathus, and Plethodon. The tendency thus far has been for researchers to study a few species in detail, rather than to examine superficially numerous
To examine the hypothesis that male desert iguanas can distinguish their own scent from that of other males, the responses of male desert iguanas to their own secretions with their responses to secretions from unfamiliar male conspecifics were compared. The observed behavioral differences between treatments indicated that male desert iguanas are capable of detecting and responding differentially to their own femoral gland secretions and those of unfamiliar conspecifics. Although results were suggestive of a scent-matching recognition mechanism,
they were consistent with the existence of either self and/or individual recognition abilities.
Tongue-flicking is a synapomorphy of squamate reptiles functioning to sample chemicals for vomerolfactory analysis, which became possible in primitive squamates when ducts opened from the vomeronasal organs to the roof of the mouth. Extant iguanian lizards in families that do not use the tongue to sample chemical prey cues prior to attack partially protrude it in two feeding contexts: during capture by lingual prehension and after oral contact with prey. These lizards do not exhibit strike-induced chemosensory searching. Lingual prey prehension is present in iguanian lizards and inSphenodon, the sister taxon of Squamata. During attempts to capture prey, the tongues of primitive squamates inevitably made incidental contact with environmental substrates bearing chemicals deposited by prey, conspecifics, and predators. Such contact presumably induced selection for tongue-flicking and ability to identify biologically important chemicals. Most iguanian lizards are ambush foragers that use immobility as a major antipredatory defense. Because tongue-flicking at an ambush post would not allow chemical search beyond the vicinity of the head and would render them easier for predators and prey to detect, typical iguanians tongue-flick neither while foraging nor to identify predators. They do detect pheromones by tongue-flicking. Scleroglossan lizards are typically active foragers that rely on speed to escape. Being freer to move the tongue, they have evolved lingual sampling allowing detection of chemical cues of conspecifics, predators, and prey, as well as strike-induced chemosensory searching, some can follow pheromone trails by tongue-flicking. Some families have lingual morphology and behavior specialized for chemosensory sampling. In varanids and snakes, the taxa showing the greatest lingual specialization, additional prey-related chemosensory behaviors have evolved. In iguanian and scleroglossan families that have secondarily adopted the foraging mode typical of the other taxon, prey chemical discrimination involving tongue-flicking and strike-induced chemosensory searching are typical for the foraging mode rather than the taxon. Because foraging mode and state of prey chemical discrimination are stable within squamate families and to a large extent in higher taxa, both features have been retained from the ancestral condition in most families. However, in three cases in which foraging mode has changed from its ancestral state, the state of prey chemical discrimination has also changed, indicating that prey chemical discrimination is adaptively adjusted to foraging mode. Indeed, acquisition of lingually mediated prey chemical discrimination may have made feasible the evolution of active foraging, which in turn appears to have profoundly influenced the further evolution of squamate chemosensory structures and behavior, placing a selective premium on features enhancing the tongue's efficiency as a chemical sampling device. The advent of tongue-flicking to sample prey chemicals and thus detect hidden prey may have allowed generalist (cruise) or ambush foragers, if early squamates were such, to become specialists in active foraging. Alternatively, if the common ancestors of squamates were active foragers, the adoption of ambush foraging would have selected against participation of the tongue in locating prey. Acting jointly, tongue-flicking and active foraging have had momentous consequences for squamate diversification. Specialization for active foraging would appear to have had ramifying effects on antipredatory defenses, body form, territoriality, mating systems, and reproductive physiology.
Male red-backed salamanders, Plethodon cinereus, were used to test the hypothesis that the post-cloacal gland produces scents for territorial marking. Experiment 1 tested the reaction of intruders to substrates marked with the products of the post-cloacal gland, those of the granular glands from the thoracic region (sham control), and unmarked substrates. To ensure that only certain glands were capable of marking substrates, glands were blocked by applying a synthetic bilayer. Intruders preferred substrates marked by previous residents with products of the post-cloacal gland and granular glands of the thoracic region over substrates that had not been marked. In experiment 2, observations were made of the interactions of intruders and residents when intruders were introduced into the residents' areas. Residents were blocked so that their substrates could only be marked with products of either the post-cloacal gland or the granular glands from the thoracic region. Residents spent more time in aggressive postures in trials where they had marked the substrate with the products of the post-cloacal gland compared with trials in which they had marked the substrate with products of the granular glands of the thoracic region. In addition, intruders initiated contact for longer periods than residents in both types of trials. The results of these two experiments suggest that the post-cloacal gland produces territorial scent marks and that scent marks do not cause avoidance by conspecifics.
Chemical communication is widespread among plethodontid salamanders (Caudata: Plethodontidae), but little information exists on the role of odours in interspecific competition in general and among species in western North America in particular. The present study examined the potential of faecal odours for intra- and interspecific communication among sympatric plethodontids in two-choice tests in the laboratory. In experiment 1, Plethodon vehiculum and Aneides ferrus from Vancouver Island, B.C., Canada, were presented with two burrows marked with (1) a faecal pellet of male P. vehiculum versus a control clay pellet, and (2) a faecal pellet of male A. ferreus versus a control pellet. In experiment 2, responses of P. vehiculum, P. dunni and P. vandykei from Washington, U.S.A., were tested towards faecal pellets of conspecific males and females, and towards pellets of congeneric males. Both P. vehiculum and P. dunni distinguished odours of conspecific males and females, based on their behavioural responses towards faecal and control pellets. Only P. dunni, however, avoided burrows marked with faeces of conspecific individuals. In contrast, neither A. ferreus nor P. vandykei appeared to distinguish faecal odours of conspecific salamanders from control pellets. In tests with odours of heterospecific individuals, P. dunni and P. vehiculum distinguished odours of each other, and P. vandykei distinguished odours of P. vehiculum. The data from these two experiments suggest that P. dunni use faecal pellets as territorial markers both in intraspecific communication and in interspecific encounters with P. vehiculum.
Relations between structure, function, and constraint in the chemical communication systems of terrestrial vertebrates are examined from a design-feature perspective. A survey of chemical signals from 34 mammalian species indicates variation in the chemical structure of signals that are used in different social contexts and under different environmental conditions. Behavioral, physiological, and morphological adaptations in the emission and reception of chemical signals in terrestrial vertebrates are reviewed. Several features of chemical signals, including temporal parameters, spatial range, localizability, intensity and detectability, and information content, appear to be adjusted for particular social functions, subject to constraints of the signaling environment. In many cases, these adaptations may minimize energetic costs to signaling animals.
Many lizards use caudal autotomy as an antipredatory strategy. We experimentally examined the effect of tail loss on the time-budgets, movement patterns, and home range size of the Iberian rock lizard Lacerta monticola in the field during the mating season. Our results indicate that tail loss did not alter most variables in male and female time-budgets but did affect the time spent moving and movement patterns of males. Tailless males spent less time moving and, when moving, more time on rocks, with shorter movements, more pauses, and less time on bushes than did tailed ones. Home range size was smaller in tailless males but did not differ between tailed and tailless females. The results suggest that tailless males may compensate the survival cost of autotomy by modifying their use of space and time; as a result, however, they may incur lower access to females.
The consequences of tail loss on the thermal biology of high-altitude rock lizards (Lacerta monticola) were studied by comparing field body temperatures, selected body temperatures in a gradient, and behavioural patterns of thermoregulation of tailed and tailless lizards in the field. Neither field nor selected body temperatures differed significantly between these groups. Time spent basking, mean duration of basking, and basking frequency did not differ between tailed and tailless lizards. Tailless lizards seemingly adjusted for running impairment by using rocks to a greater extent than did tailed lizards, and low morning body temperatures by increasing maximal duration of basking periods and keeping shorter distances to the nearest refuge. Tailless lizards modify thermoregulatory behaviour, but obtain the same thermoregulatory precision as tailed lizards, possibly allowing maximization of physiological processes linked to tail regeneration.
Habitat preferences in lizards are often associated with specific morphological traits and locomotor behavior. Caudal autotomy occurs in many lizards and is often used for escape from predators. Autotomy produces an immediate benefit in terms of survival, although associated costs during tail regeneration may reduce individual fitness. Tail loss may affect the efficiency with which lizards use their habitat. We investigated experimentally the effect of tail loss on microhabitat use in a population of the Iberian rock lizard, Lacerta monticola. Significant differences in microhabitat use were not detected between tailed and tailless lizards during the reproductive season (spring), but during summer tailless lizards were more often associated with rocks and used grassy and bare ground less than did tailed lizards. Conflicting requirements during reproductive versus non reproductive seasons may explain that tailless lizards do not modify microhabitat use during spring by means of behavioral flexibility.
This study deals with several features of the reproductive biology of Lacerta monticola cyreni. It was carried out in a lizard population in the Sierra de Guadarrama (Central Spain). Owing to the hard weather conditions the lizards have a very short active season (nearly six months). The annual gonadal cycle of both sexes shows an unimodal distribution which demonstrates the existence of only one mating and only one clutch per year. Mating occurs in May-June. Females lay a clutch of 4 to 9 eggs, usually during July. Finally, hatching takes place in September, one month before the beginning of hibernation in October.
Conventionally, statistical significance is determined by setting a Type I error rate of 5% for each test. However, interpreting collections of multiple tests based on comparison-wise significance levels results in a high probability that at least some tests are significant by chance alone. Uncommon occurrences become highly probable over multiple tests. Use of simultaneous-inference techniques to control Type I error rates over collections of multiple tests is advisable when 2 or more individual statistical tests address a common null hypothesis, when
P-values from a group of related tests are examined a posteriori for significant values, and when multiple statistical tests are conducted sequentially or with different permutations of the same data. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
The ability of 10 captive male green iguanas, Iguana iguana, to discriminate between their own femoral gland secretions and those of familiar and unfamiliar conspecific males was investigated. Results of behavioral tests conducted during breeding season provided preliminary support for the hypothesis that femoral gland lipids permit initial detection of secretion deposits through the chemoreception of volatiles, whereas low volatility proteins provide more detailed information regarding the identity of the signaler after secretion deposits are localized.
Detection of conspecific chemical stimuli and their use to discriminate males from females is demonstrated in an amphisbaenian, Blanus cinereus. In two experiments using randomized blocks designs, males were presented cotton swabs bearing male stimuli, female stimuli, and deionized water in counterbalanced sequence. Detection of conspecific stimuli was evident by the significantly higher tongue-flick rates by male subjects in response to chemical stimuli from precloacal pores and trunk skin of both sexes than from a control stimulus. Differential response was indicated by a significantly greater tongue-flick rate in response to female than to male precloacal pore stimuli. That more males bit applicators bearing conspecific male precloacal pore stimuli than the other stimuli also suggests functional recognition of males. That tongue-flick rates for male and female trunk skin stimuli were indistinguishable suggests that tongue-flicking the trunk skin does not allow sex recognition and that sex pheromones are not present in that region. Latency to the first tongue-flick was shorter in response to precloacal pore stimuli of females than that of males, suggesting that volatile pheromonal components most likely detected by olfaction elicit tongue-flicking. Because the sensory basis for discriminations based on tongue-flicking is presumably vomerolfaction, the possibility must be considered that olfaction contributes to the tongue-flicking rate for pheromonal responses involving analysis of lingually sampled pheromones by the vomeronasal system to both initial and later responses. Because pheromonal responses by B. cinereus are similar to those in scleroglossan lizards and snakes, the closest relatives of amphisbaenians, pheromonal communication may be plesiomorphic in this taxon. It may be selectively important in amphisbaenians due to fossoriality and reduced vision.
Western fence lizards, Sceloporus occidentalis, were exposed to markings, droppings, and exudates (e.g., femoral and proctodeal gland secretions, and feces) collected from conspecific males and females in a chemicalcue, simultaneous discrimination procedure. Females performed no discrimination between unmarked brick surfaces and those labelled by conspecifics of either sex, as indexed by relative numbers of substrate licks or tongue flicks. Males performed significantly more of these actions to male- but not female-labelled surfaces. Immediately subsequent to licks of labelled surfaces, but never after licks of unlabelled surfaces, both sexes performed push-ups, a visual display in this genus. These findings suggest that these lizards are capable of discriminating and utilizing chemical signals as a mode of social communication, and that chemical signals alone are capable of releasing a visual display from conspecifics.
Behavioural tests comparing the responses of desert iguanas, Dipsosaurus dorsalis, to conspecific femoral gland secretions and to controls showed that the secretions are relatively non-volatile, but possess pheromonal activity at close range. Low volatility ensures that these secretions remain in the environment longer, but makes signal localization by airborne olfactory cues difficult. Spectroscopic analyses of desert iguana femoral gland secretions revealed that they strongly absorb longwave ultraviolet light. Behavioural bioassays in which lizards were presented with secretion-marked and blank control tiles under both ultraviolet and incandescent light conditions demonstrated the importance of an ultraviolet light source for successful detection of femoral gland deposits. Further tests measuring the lizards' success rate in localizing an ultraviolet-absorbing ink spot under ultraviolet and incandescent light conditions suggested desert iguanas have visual sensitivity in the near ultraviolet part of the light spectrum. The existence of an ultraviolet visual marker provides a possible mechanism for locating these low volatility pheromones.
This chapter discusses on the individual odors among mammals and their possible role in communicating individual identity. The origins of these odors, their possible significance inside and outside of communication systems, and their possible functions are addressed. An odor that conveys information on individual identity may also carry information about other characteristics of the animal, such as its species, sex, age, and motivational state. It appears that once individual odors evolved, whether as a result of direct selective pressures or as by-products of other biological processes, they were exploited and adapted for a large variety of different purposes. This suggests that there is no one primary function of individual odors; rather they are used opportunistically and may serve many different functions depending on the evolutionary history, ecology, and social structure of the species in question.
1. The aim of this paper has been to review the theory behind kin recognition to examine the benefits individuals obtain by recognizing their kin and to review the mechanisms used by individuals in their recognition of kin.
2. The ability to discriminate between kin and non-kin, and between different classes of kin gives individuals advantages in fitness greater than individuals unable to recognize their kin. Four specific areas of benefit were considered: altruistic behaviour, co-operative behaviour, parental care and mate choice. Finally the possibility that kin recognition has arisen as a byproduct from some other ability was discussed.
3. Mechanisms of kin recognition were considered with respect to three essential components of kin recognition. The cue used to discriminate kin, how individuals classify conspecifics as kin, etc. and how the ability to recognize kin develops.
4. Individuals can use a number of cues to discriminate kin from non-kin. These were divided into cues presented by conspecifics (conspecific cues), of which three types were considered: individual, genetic and group/colony cues, and non-conspecific cues, environmental, state and no cues. Kin recognition could be achieved by use of all these cues.
5. How individuals classify their conspecifics as kin, etc. can be achieved in a number of ways; dishabituation or self-matching, which require no learning of kinship cues, or by phenotype matching or familiarity, both of which require the learning of kinship information.
6. It may be necessary for individuals to acquire information concerning kinship. This may be learned, and can be achieved in a number of ways; physiological imprinting, exposure learning or associative learning. Acquisition by these means is non-selective, in that the cues which are most salient in the individual's environment will be learned. Selectivity can be introduced into this process to increase the probability of acquiring kinship information by a number of means; learning from parents, sensitive periods for learning and prenatal learning. Finally, kinship information could be supplied by recognition genes.
7. A distinction is drawn between cues which are used by an individual in the discrimination of kin, discriminators, and cues which are used by individuals in the acquisition of information about kinship, acquisitors.
8. Experiments used to support previous categories of mechanisms of kin recognition were examined in the light of this discussion and it was found that the results were open to a number of different interpretations and yielded little specific information about the mechanisms of kin recognition.
9. It was concluded that there was much evidence, both theoretical and experimental to support the proposed benefits individuals gain from recognizing kin, but much more research is required before the mechanisms of kin recognition are fully understood.
The abstract for this document is available on CSA Illumina.To view the Abstract, click the Abstract button above the document title.
A laboratory experiment was performed to test the hypothesis that male red-backed salamanders (Plethodon cinereus) use pheromones contained in faecal pellets to identify male-marked territories. Each of 25 males was tested randomly under four conditions: (1) a burrow marked with its own faecal pellet versus one marked with a conspecific's pellet; (2) own-marked versus surrogate-marked burrows (the surrogate being a pellet of wadded paper); (3) conspecific-marked versus surrogate-marked burrows; and (4) a control of two surrogate-marked burrows. Males spent significantly more time in own-marked than in conspecific-marked burrows and significantly more time in surrogate-marked than in conspecific-marked burrows. Males favoured own-marked over surrogate-marked burrows. No position bias was found in the control. Males spent significantly more time nose-tapping (olfactory sampling) to a conspecific's pellet when it was paired with a surrogate but showed no differences in the other three tests. Significantly more time was spent in a submissive posture in front of the conspecific-marked burrow than in front of either their own-marked or the surrogate-marked burrows; no difference was found between own-marked versus surrogate-marked burrows or in the control. Time spent in the threat posture did not differ significantly between burrows in any condition. These data permit the inferences that males of P. cinereus use faecal pellets to mark and identify territories, avoid or display submissively toward burrows marked by conspecific males, and prefer own-marked shelters.
This is a book review by A. W. F. Edwards (published in Biometrics, 31(2) 229-230) of my books Biometry (by Sokal and Rohlf) and Statistical Tables (by Rohlf and Sokal) both published in 1981.
This paper reviews experimental and field studies on scent marking behaviour. The occurrence and effects of scent marking are considered in particular, and a number of areas for further research are made apparent. Marking behaviour in mammals is often stated to be ‘territorial’ or, more specifically, to play a role in territorial defence. In fact there is a shortage of evidence to support this view; many of the relevant observations are anecdotal or interpreted with preconceived notions of function in mind. While marking is clearly associated with aggressive behaviour in many species and may therefore be related in some way to territorial behaviour, its role in aggression is not understood. Moreover, there is evidence to support a number of other theories of function some of which are unrelated to territory. It seems that, as with any other mode of communication, scent marking has become adapted for use in a variety of contexts. It probably has more than one function in any one species and different functions in different species.
Adult male and female red-backed salamanders, Plethodon cinereus, gain information about gender and body size of conspecifics through chemical signals. Responses to information about gender differed between the sexes: females produced faecal pellets (territorial pheromonal markers) fastest when exposed to their own pheromones while males produced faecal pellets fastest when exposed to pheromones of females. These data suggest that for females the primary pheromonal function of faecal pellets is advertisement (i.e. defence) of their own areas, and that faecal pellets produced by males are of primary importance in the attraction of mates. Two types of responses to information concerning body size were found. (1) Both male and female intruders exposed to the pheromones of resident males tended to produce larger faecal pellets when the intruder and resident were of similar body sizes. This phenomenon was not observed when the resident was female. (2) Male intruders were significantly more aggressive when exposed to the pheromones of individuals of similar body size and more submissive when exposed to pheromones of individuals that were larger. Therefore, information about body size (an indicator of competitive ability) of males may be transmitted via chemical signals and may cause changes in the behaviour of conspecifics.
Scent marking by resource holders: alternative mechanisms for advertising the cost of competition
- Tierpsychol
- L M Gosling
Tierpsychol. 60, Gosling, L. M. 1990: Scent marking by resource holders: alternative mechanisms for advertising the cost of competition. In: Chemical Signals in Vertebrates 5 (Macdonald, D. W., Miiller-Schwarze, D. & Natynczuk, S. E., eds). Oxford Univ. Press, Oxford. pp. 315--328.
Some Methods for the Statistical Analysis of Samples of Bentic Invertebrates Further data on the reproduction of Lacertu rnonticolu cyreni (Sauria, Lacertidae) in Central Spain. Amphibia-Reptilia 6, 173.-179. tion
- J M Elliot
- B Elvira
- C R Vigal
Elliot, J. M. 1971: Some Methods for the Statistical Analysis of Samples of Bentic Invertebrates. Freshwater Biol. Assoc. Sci. Publ. 25, London. Elvira, B. & Vigal, C. R. 1985: Further data on the reproduction of Lacertu rnonticolu cyreni (Sauria, Lacertidae) in Central Spain. Amphibia-Reptilia 6, 173.-179. tion. Anim. Behav. 38, 129-137. vertebrates. Am. Nat. 139, 62-89.
Reptilian pheromones
- R T Mason
Mason, R. T. 1992: Reptilian pheromones. In: Biology of the Reptilia, Vol. 18 (Cans, C. & Crews, D., eds). Univ. of Chicago Press, Chicago. pp. 1 14-228.
Iberische Gebirgseidechse Aula Verlag, Wiesbaden, Germany. pp. 276-289. iguanas, Dipsosuurus dorsalis
- A Salvador
Salvador, A. 1984: Lucrrtu moniicolu Boulenger, 1905. Iberische Gebirgseidechse. In: Handbuch der Reptilien und Amphibien Europas, Vol. 2/1 (Bohme, W., ed.). Aula Verlag, Wiesbaden, Germany. pp. 276-289. iguanas, Dipsosuurus dorsalis. J. Herpetol. 19, 541---544. 89-1 18.
C. 0 " . 1985: Individual recognition in free-living adult male desert Gosling, L. M. 1982: A reassessment of the function of scent marking in territories
- P Lbpez
- P Aragon
- J Martin
- T H Glinsky
- Krekorian
P. Lbpez, P. Aragon & J. Martin Glinsky, T. H. & Krekorian. C. 0 ". 1985: Individual recognition in free-living adult male desert Gosling, L. M. 1982: A reassessment of the function of scent marking in territories.