No full-text available
To read the full-text of this research,
you can request a copy directly from the author.
Experiments on color changes and regeneration in the crab-Spider, Misumena vatia
... Crab spiders usually match the color of their background (Mascord 1970;Morse 2007). Some species even have debris attached to their bodies, making them more similar to their bark background (Gawryszewski 2014), whereas some flowerdwelling species change their body color to that of their flower (Packard 1905;Gabritschevsky 1927;Théry 2007;Morse 2007;Insausti and Casas 2009). The best-studied crab spider, Misumena vatia, changes its body coloration over 10-20 days when transferred from white to yellow flowers and vice versa (Packard 1905;Gabritschevsky 1927). ...
... Some species even have debris attached to their bodies, making them more similar to their bark background (Gawryszewski 2014), whereas some flowerdwelling species change their body color to that of their flower (Packard 1905;Gabritschevsky 1927;Théry 2007;Morse 2007;Insausti and Casas 2009). The best-studied crab spider, Misumena vatia, changes its body coloration over 10-20 days when transferred from white to yellow flowers and vice versa (Packard 1905;Gabritschevsky 1927). Nonetheless, background matching is not the only strategy found in crab spiders. ...
... We visually searched for specimens on flowers and bark, and sampled the vegetation using a sweep net. Because the females of some species of crab spider are able to change color (Packard 1905;Gabritschevsky 1927;Morse 2007;Thery 2007) and others present a color polymorphism (Ibarra and Reader 2014), we aimed to collect several individuals per population to detect variation in their reflectance properties. For our study, we were not able to use museum collection material, as color is affected by the fixation and storage procedures. ...
The evolution of a visual signal will be affected by signaller and receiver behaviour, and by the physical properties of the environment where the signal is displayed. Crab spiders are typical sit-and-wait predators found in diverse ambush sites, such as tree bark, foliage and flowers. Some of the flower-dweller species present a UV(+) -white visual lure that makes them conspicuous and attractive to their prey. We hypothesised that UV(+) -white colouration was associated with the evolution of a flower-dwelling habit. In addition, following up on results from a previous study we tested whether the UV(+) -white colouration evolved predominantly in flower-dwelling species occurring in Australia. We measured the reflectance of 1149 specimens from 66 species collected in Australia and Europe, reconstructed a crab spider phylogeny, and applied phylogenetic comparative methods to test our hypotheses. We found that the flower-dwelling habit evolved independently multiple times, and that this trait was correlated with the evolution of the UV(+) -white colouration. However, outside Australia non-flower-dwelling crab spiders also express a UV(+) -white colouration. Therefore, UV(+) -white reflectance is probably a recurring adaptation of some flower-dwellers for attracting pollinators, although it may have other functions in non-flower-dwellers, such as camouflage. This article is protected by copyright. All rights reserved.
... Most of the research has focused on Misumena vatia (Clerck) (e.g. Gabritschevsky, 1927;Chittka, 2001), Thomisus onustus Walckenaer (e.g. Heckel, 1891;Théry & Casas, 2002), and Thomisus spectabilis Doleschall (e.g. ...
... The rate of colour change in crab spiders has previously been estimated only subjectively with no quantification of colour. For example, Packard (1905) stated that M. vatia changed from white to yellow within a 'week to 10 days' in the field and Gabritschevsky (1927) reported that under artificial conditions it took 10-25 days for M. vatia to change from white to yellow and less time (2-6 days) to go from yellow to white. More recently, Théry (2007) gave a contrasting report for the same species by stating that the time required to change from yellow to white under artificial light was longer than the reverse, and suggested that this might indicate a greater cost to degrade the colour compounds. ...
... Nevertheless, we are able to report that the full transition by females from white to yellow sometimes occurred as quickly as 3 days. This is generally faster than the qualitative estimates of 6-10 days (Packard, 1905) or longer (Gabritschevsky, 1927) for the same direction of change in the closely related M. vatia. More significantly, the behaviour that prevented a full quantitative comparison of colour change directions, i.e. departures by yellow females from white flowers, is actually consistent with the differential costs hypothesis. ...
1. Changing between white and yellow body colour in certain crab spider species has been interpreted as an adaptation for matching the background colour where they hunt and thereby remaining cryptic to prey and/or their own predators. The potential costs and benefits of colour change in female M isumenoides formosipes W alckenaer were investigated via assessment of prey opportunities and capture success, in conjunction with the tendency for and rate of colour change on different backgrounds.
2. It was tested whether being matched or mismatched to their background affected foraging by moving females between white and yellow inflorescences. Female colour was quantified in digital photos using the L ab colour space component of A dobe photoshop , providing the first empirical assessment of the rate of colour change for a crab spider species.
3. Insect visits (potential prey) on inflorescences with and without spiders and prey capture success with females matched and mismatched to their background were quantified.
4. Yellow females abandoned white inflorescences, whereas white females remained on and underwent colour change on yellow inflorescences. This difference supported the notion that the costs of colour change differ depending on the starting colour. Female departures from white flowers were apparently not due to a lack of insect visitation, as white inflorescences had higher visitation rates than did yellow inflorescences, even in the presence of spiders.
5. An increase in the prey capture success of females who transitioned from white to yellow body colour on a yellow background supported the hypothesis that colour matching functions to deceive prey.
... Thomisus and Misumena), and these usually appear to humans as white, yellow, pink or red (Mascord 1970;Morse 2007). These spiders are able to change colour over several days (Packard 1905;Gabritschevsky 1927), and intermediates between these colours can be found (pers. obs.; Gawryszewski, Llandres & Herberstein 2012). ...
... Some crab spider species are thought to increase their rate of pollinator captures by manipulating the degree of visual contrast against their floral backgrounds, both in human-visible and ultraviolet (UV) wavelengths of light (Packard 1905;Gabritschevsky 1927;Th ery 2007;Gawryszewski, Llandres & Herberstein 2012). Misumena vatia, for instance, are usually yellow when found on yellow flowers, but white when found on white flowers (Packard 1905;Gabritschevsky 1927), and take 10-20 days to colour-match when transferred from one colour background to the other (Gabritschevsky 1927). ...
... Some crab spider species are thought to increase their rate of pollinator captures by manipulating the degree of visual contrast against their floral backgrounds, both in human-visible and ultraviolet (UV) wavelengths of light (Packard 1905;Gabritschevsky 1927;Th ery 2007;Gawryszewski, Llandres & Herberstein 2012). Misumena vatia, for instance, are usually yellow when found on yellow flowers, but white when found on white flowers (Packard 1905;Gabritschevsky 1927), and take 10-20 days to colour-match when transferred from one colour background to the other (Gabritschevsky 1927). Some species also selectively reflect UV light (Heiling, Herberstein & Chittka 2003;Herberstein, Heiling & Cheng, 2009), tuning their attractiveness to receivers sensitive to this spectral range (Heiling et al. 2005). ...
The astounding diversity of animal coloration is indicative of a wide variety of selection pressures. Despite great interest in adaptive function, detailed understanding of the constituent elements of colour traits is lacking for many systems. Such information is important in allowing more accurate appraisals of colour variation and its potential production costs.
In this study, we ‘dissect’ the dorsal colour of crab spiders (Thomisidae) to examine the mechanistic basis of a polyphenic colour trait. These spiders possess the ability to alter reflectance in the ultraviolet ( UV ), violet and blue wavelengths, changing their colour within days. We investigate and compare the proximate mechanistic basis of colour production in multiple phenotypes of three species using histology and spectrophotometry.
Our analyses indicate that the spider cuticle is not equivalently transparent to light across the spectrum (300–700 nm) – as previously argued – and contributes to colour variation. UV light is reflected from guanine crystals, present in storage cells ventral to the hypodermis. The crystals are exposed through a partially UV ‐transmitting hypodermis and cuticle. Variation from white to yellow is likely mediated through pigments/crystals present in different oxidative stages in the hypodermal cells.
Simple mechanistic changes are therefore necessary to produce the observed variation, and likely underlie the evolutionary and ontogenetic lability of this trait. Our findings imply that either a UV ‐reflective abdomen was the ancestral state for crab spiders, or, if pre‐dated by UV ‐absorbent hypodermal pigments, the evolution of UV reflection has only involved the exposure of underlying guanine crystals through an otherwise clear hypodermis.
... Whilst some of the metabolites involved in M. vatia colour production have been identified (Riou and Christidès, 2010), nothing is known about the internal hormonal mechanisms controlling colour production. Prey and light reflected by the background have been shown to be important external factors in determining colour change in crab spiders (Gabritschevsky, 1927; Rabaud, 1919; Théry, 2007): individuals presented with a yellow background and fed red-eyed flies better matched the yellow background, whilst individuals submitted to white background and fed white-eyed flies better matched the white background (Théry, 2007). However, variability in response was very high as many individuals were found to remain white despite being submitted to yellow stimuli. ...
... In the case of crab spiders, further work is needed to understand which other factors, together with background colour, trigger colour change towards yellow under natural conditions. Previous studies with M. vatia spiders have successfully manipulated their colouration in response to background (Gabritschevsky, 1927; Rabaud, 1919) but explain very little about the details of colour change dynamics. Colour changes were found to take 10–25days (white to yellow) or 5–6days (yellow to white), suggesting that the average speed of change from yellow to white is 3.18 times faster than from white to yellow. ...
... In contrast to non-reversible ontogenetic colour change (for which colour determination is associated with growing events), we found that T. onustus colour change could also occur independently of moulting. Although colour change in crab spiders has been the subject of several studies (Gabritschevsky, 1927; Rabaud, 1919; Théry, 2007), our work is the first to show an association between colour change and moulting events in this species. Our results regarding the effect of moulting on colour change are in accordance with previous studies of animals that change colour reversibly. ...
Habitat heterogeneity that occurs within an individual's lifetime may favour the evolution of reversible plasticity. Colour reversibility has many different functions in animals, such as thermoregulation, crypsis through background matching and social interactions. However, the mechanisms underlying reversible colour changes are yet to be thoroughly investigated. This study aims to determine the environmental and hormonal factors underlying morphological colour changes in Thomisus onustus crab spiders and the biochemical metabolites produced during these changes. We quantified the dynamics of colour changes over time: spiders were kept in yellow and white containers under natural light conditions and their colour was measured over 15 days using a spectrophotometer. We also characterised the chemical metabolites of spiders changing to a yellow colour using HPLC. Hormonal control of colour change was investigated by injecting 20-hydroxyecdysone (20E) into spiders. We found that background colouration was a major environmental factor responsible for colour change in crab spiders: individuals presented with white and yellow backgrounds changed to white and yellow colours, respectively. An ommochrome precursor, 3-OH-kynurenine, was the main pigment responsible for yellow colour. Spiders injected with 20E displayed a similar rate of change towards yellow colouration as spiders kept in yellow containers and exposed to natural sunlight. This study demonstrates novel hormonal manipulations that are capable of inducing reversible colour change.
... The ability of certain species within the family Thomisidae (crab spiders) to undergo a reversible color change depending on their environmental substrate, a process referred to as a morphological color change (Holl 1987), has provoked interest among naturalists since the late nineteenth century (Angus 1882;Packard 1905;Gadeau de Kerville 1907;Gabritschevsky 1927;Gertsch 1939;Weigel 1941). Most investigations of morphological color changes among thomisids have focused on the goldenrod spider, Misumena vatia (Clerck 1757) (e.g., Packard 1905;Gabritschevsky 1927;Millot 1926;Weigel 1941), and the ability to change color has been attributed only to adult females (Gabritschevsky 1927). ...
... The ability of certain species within the family Thomisidae (crab spiders) to undergo a reversible color change depending on their environmental substrate, a process referred to as a morphological color change (Holl 1987), has provoked interest among naturalists since the late nineteenth century (Angus 1882;Packard 1905;Gadeau de Kerville 1907;Gabritschevsky 1927;Gertsch 1939;Weigel 1941). Most investigations of morphological color changes among thomisids have focused on the goldenrod spider, Misumena vatia (Clerck 1757) (e.g., Packard 1905;Gabritschevsky 1927;Millot 1926;Weigel 1941), and the ability to change color has been attributed only to adult females (Gabritschevsky 1927). ...
... The ability of certain species within the family Thomisidae (crab spiders) to undergo a reversible color change depending on their environmental substrate, a process referred to as a morphological color change (Holl 1987), has provoked interest among naturalists since the late nineteenth century (Angus 1882;Packard 1905;Gadeau de Kerville 1907;Gabritschevsky 1927;Gertsch 1939;Weigel 1941). Most investigations of morphological color changes among thomisids have focused on the goldenrod spider, Misumena vatia (Clerck 1757) (e.g., Packard 1905;Gabritschevsky 1927;Millot 1926;Weigel 1941), and the ability to change color has been attributed only to adult females (Gabritschevsky 1927). ...
The effect of dietary pigments on abdominal color of juvenile spiders was examined in the laboratory using the flower-dwelling crab spiders Misumenops asperatus (Hentz 1847), Misumenoides formosipes (Walckenaer 1837), and Misumena vatia (Clerck 1757) (Thomisidae). Because these species lack hypodermal chromes, ingested prey pigments may show through the epidermis and affect opisthosomal coloration. Diet-induced color changes were restricted to the opisthosoma, and all three spider species responded similarly to dietary pigments. Opisthosomas of instars 2–4 fed red-eyed fruit flies turned pink, and the pink color faded back to the normal white over a period of 4–6 days. Opisthosomas of instars 5–7 fed red-eyed fruit flies remained white, as did opisthosomas of all instars fed white-eyed fruit flies (controls). In a field population of M. asperatus, 82% of spiders in July (instar 2), 93% of spiders in August (instars 3–4), and 8% of spiders in September (instar 5) had pink, orange, or brown opisthosomas. Yellow juveniles were also seen: 5% and 57% of M. asperatus observed in August and September, respectively, were yellow. Yellow juvenile M. formosipes were observed in the field as well. The yellow color did not result from dietary pigments, but was, rather, a morphological color change and included the prosoma and limbs, as well as the opisthosoma.
... In addition, light reflected by the white experimental background contained significant blue wavelengths which crab spiders have never been shown to reflect, which explains why white matching was even worse than yelloweUV matching. Alternatively, 2 weeks might not have been long enough to have revealed the full capacity of spiders to change colour, which takes between 10 and 25 days to turn from white to yellow on a yellow background (Gabritschevsky 1927). However, this explanation is unlikely since the reversion to white, which has been suggested to take 4e6 days (Gabritschevsky 1927; Schmalhofer 2000), was also not fully revealed within the 2 weeks of the experiments. ...
... Alternatively, 2 weeks might not have been long enough to have revealed the full capacity of spiders to change colour, which takes between 10 and 25 days to turn from white to yellow on a yellow background (Gabritschevsky 1927). However, this explanation is unlikely since the reversion to white, which has been suggested to take 4e6 days (Gabritschevsky 1927; Schmalhofer 2000), was also not fully revealed within the 2 weeks of the experiments. Even if the present experimental protocol reduced the spiders' camouflage ability compared to natural conditions, the spectrum of light reflected by the visual background had a highly significant effect on colour change, confirming previous observations using human vision (Rabaud 1918Rabaud , 1919 Gabritschevsky 1927; Weigel 1941). ...
... However, this explanation is unlikely since the reversion to white, which has been suggested to take 4e6 days (Gabritschevsky 1927; Schmalhofer 2000), was also not fully revealed within the 2 weeks of the experiments. Even if the present experimental protocol reduced the spiders' camouflage ability compared to natural conditions, the spectrum of light reflected by the visual background had a highly significant effect on colour change, confirming previous observations using human vision (Rabaud 1918Rabaud , 1919 Gabritschevsky 1927; Weigel 1941). The fact that spiders eating coloured prey were less efficient at matching the white than the yellow background indicates that it may be more difficult to degrade compounds used for coloration than to release them. ...
The ability to change body coloration is widely used in the context of visual camouflage to hide from predators or prey. Although experimental evidence from human vision shows that background and prey eye colours may trigger adaptive colour change in crab spiders, no study has addressed this hypothesis in the perceptual colour space of either predator or prey. I simultaneously tested the effects of reflected light and prey eye colours on background matching of female crab spiders, Misumena vatia. Using spectror- adiometric measurements and modelling of perceptual colour space of the most frequent prey, I tested whether individual spiders were able to match white and yellow light reflected by artificial backgrounds when fed either white- or red-eyed fruit flies, Drosophila melanogaster. The colour of light reflected by the visual background triggered adaptive camouflage as seen by Hymenopteran prey. In addition, there was a significant effect of prey eye colour within each light colour experiment, with spiders fed white- eyed flies better matching light reflected by the white background, and spiders fed red-eyed flies better matching the yellow reflected light. However, only spiders exposed to yellow reflected light and fed red- eyed flies could approach the colour detection threshold calculated for Hymenoptera. These results provide insights into how colour change is triggered in crab spiders, and indicate that ommochrome pigments in- gested with prey eyes not only are used by crab spiders to adjust their adaptive coloration, but also may indicate the hunting ability of females to potential mates
... Vision plays a main role in different aspects of spiders' biology, including spatial orientation, prey capture, predator detection, courtship, substrate choice and probably morphological color changes, as in Misumena vatia (Homann, 1934;Weigel, 1941;Land, 1969a,b;Land, 1971;Hill, 1979;Foelix, 1996;Oxford and Gillespie, 1998;Dacke et al., 1999Dacke et al., , 2001Defrize et al., 2010). ...
... It has been generally assumed that vision plays a major role in the color change of M. vatia. Several studies have revealed not only that reflected light from the substrate influences color change (Gabritchevsky, 1927;Théry, 2007;Théry et al., 2010), but also that white spiders fail to change their color when they are placed on a yellow background if their eyes are black-painted (Weigel, 1941). Recent conflicting evidence, however, casts doubt on those earlier results. ...
... They completely cover the visual field of AL eyes and overlap with the visual field of the other pairs. Despite a high variability in the eye pattern across spider species, a nearly full view of the upper visual environment has been highlighted in a majority of species for which visual fields has been assessed (Land, 1985;Foelix, 1996;Nørgaard et al., 2008). In M. vatia, a binocular zone is present as a vertical frontal band. ...
... Colonies of fiddler crabs that are highly exposed to bird predators have, on average, a duller colouration than less exposed colonies and there is evidence that individuals reduce their conspicuousness if the danger of predation is experimentally increased (Hemmi et al., 2006). Similar to fiddler crabs, crab spiders can change their body colour over several days (Gabritschevsky, 1927;Schmalhofer, 2000;Thery, 2007). Therefore, the difference in spider colouration between years quantified in our study may indicate that spiders are adjusting their body colouration in response to variation in predation pressure. ...
... Indeed, crab spiders fed with red-eyed Drosophila melanogaster (ommochrome rich) changed to a slightly brighter yellow colour than crab spiders fed white-eyed flies (Thery, 2007). Nonetheless, the houseflies in our experiment were red-eyed, and other species of crab spiders have changed colour even against artificial backgrounds (Gabritschevsky, 1927;Packard, 1905;Thery, 2007). In contrast to our study, crab spiders Misumena vatia did change their colouration to match the colouration of white and yellow natural and artificial backgrounds (Gabritschevsky, 1927;Packard, 1905;Thery, 2007). ...
... Nonetheless, the houseflies in our experiment were red-eyed, and other species of crab spiders have changed colour even against artificial backgrounds (Gabritschevsky, 1927;Packard, 1905;Thery, 2007). In contrast to our study, crab spiders Misumena vatia did change their colouration to match the colouration of white and yellow natural and artificial backgrounds (Gabritschevsky, 1927;Packard, 1905;Thery, 2007). However, M. vatia is apparently not UV-reflective and does not lure pollinators. ...
Sit-and-wait predators have evolved several traits that increase the probability of encountering prey, including lures that attract prey. Although most crab spiders (Thomisidae) are known by their ability to change colour in order to match the background, a few use a different strategy. They are UV-reflective, creating a colour contrast against UV-absorbing flowers that is attractive for pollinators. The nature of the relationship between colour contrast and foraging success is unknown, as is how spiders trade off the potential costs and benefits of strong colour contrast. Therefore, this study investigated the relationship between spider colouration, foraging success and background colouration in a crab spider species known to lure pollinators via UV reflectance (Thomisus spectabilis). Field data revealed that spider body condition - a proxy of past foraging success - is positively related to overall colour contrast. We experimentally tested the effect of satiation and background colour on spider colour change. Throughout the experiment, spiders changed their colour contrast regardless of their food intake, suggesting that colour contrast and the UV component contributing to overall contrast are not caused by spider condition. Although spiders responded to different backgrounds by subtly changing their body colour, this did not result in colour matching. We believe that the observed variation in colour contrast and hence conspicuousness in the field, coupled with the spiders' reaction to our manipulation, could be the result of plasticity in response to prey.
... Several taxa exhibit reversible morphological colour change, including members of the flower-dwelling crab spiders (Araneae: Thomisidae) (Gabritschevsky, 1927;Insausti & Casas, 2008), a lynx spider (Araneae: Oxyopidae) (Neck, 1978) and huntsman spider (Araneae: Sparassidae) (Holl, Lux & Holl, 1995), locusts (Orthoptera: Acrididae) (Pener & Simpson, 2009), stick insects (Phasmatodea) (Bückmann, 1977(Bückmann, , 1979, desert beetles (Coleoptera: Tenebrionidae) (Hadley, 1979;McClain et al., 1984), at least one lacewing (Neuropterida: Neuroptera: Chrysopidae) (Macleod, 1967), several stinkbugs (Hemiptera: Heteroptera: Pentatomidae) (Kotaki, 1998;Musolin, 2012), a number of caterpillars (Lepidoptera) (Nice & Fordyce, 2006;Noor et al., 2008), and many fiddler crabs (Decapoda: Ocypodidae) (Green, 1964a,b) (Table 1). While there is an emerging literature on the triggers for reversible morphological colour change in arthropods, e.g. ...
... Of the examples of backgroundmatching species, to our knowledge only studies on crab spiders have included spectral reflectance measurements and conducted visual modelling, and behavioural studies to test functional hypotheses thoroughly. Crab spiders, with their ability to change between white and yellow when positioned on white or yellow flowers, are a commonly cited example of background matching and crypsis (Gabritschevsky, 1927). However, studies using visual modelling suggest that the goldenrod crab spider (Misumena vatia) is actually chromatically (but not achromatically) conspicuous to bees and birds against some if not most floral backgrounds (Chittka, 2001;Defrize, Théry & Casas, 2010). ...
The mechanisms and functions of reversible colour change in arthropods are highly diverse despite, or perhaps due to, the presence of an exoskeleton. Physiological colour changes, which have been recorded in 90 arthropod species, are rapid and are the result of changes in the positioning of microstructures or pigments, or in the refractive index of layers in the integument. By contrast, morphological colour changes, documented in 31 species, involve the anabolism or catabolism of components (e.g. pigments) directly related to the observable colour. In this review we highlight the diversity of mechanisms by which reversible colour change occurs and the evolutionary context and diversity of arthropod taxa in which it has been observed. Further, we discuss the functions of reversible colour change so far proposed, review the limited behavioural and ecological data, and argue that the field requires phylogenetically controlled approaches to understanding the evolution of reversible colour change. Finally, we encourage biologists to explore new model systems for colour change and to engage scientists from other disciplines; continued cross-disciplinary collaboration is the most promising approach to this nexus of biology, physics, and chemistry.
... It is a sit-and-wait predator that hunts on flowers for visiting insect prey (Morse 1979;Morse & Fritz 1982). Males are tiny in relation to adult females, at times no more than 1% of the mass of gravid adult females (Gabritschevsky 1927;LeGrand & Morse 2000). Thus, they provide an opportunity to compare the activity of adult males with juvenile females of similar size. ...
... However, aside from their soft abdomen, spiders cannot increase in size except by molting, a state that profoundly affects activity and movement (Foelix 1996). Since M. vatia molt frequently (Gabritschevsky 1927), it was necessary to establish unequivocally whether the juveniles under study were influenced by impending molt, which could only be accomplished after establishing when an individual molted. It was thus also necessary to test the juveniles at both intermolt and molt periods, and we consequently present these results and comment upon them as well. ...
Adult male animals are commonly believed to exhibit higher activity than other conspe- cifics, but little information exists to compare their activity with that of other conspecifics of similar size. Here we compare the activity of adult male and similar-sized juvenile female crab spiders Misumena vatia (Araneae, Thomisidae). Adult males moved farther and more frequently than juvenile females of similar size (fourth instar) that were not affected by impending molt. Juvenile females influenced by impending or recent molt did not move as far or as frequently as nonmolting juveniles, even though their exoskeletons were hard enough to permit rapid movement. A small sample of penultimate males, of similar size to the adult males and juvenile females, exhibited activity patterns similar to the juvenile females. All of these data indicate that the high activity level of adult males is not a simple manifestation of behavior that is solely a function of size. We suggest that the high activity levels of the adult males facilitate search for scarce, cryptic mates.
... The spiders are white on flowers of most colours but become yellow on yellow flowers. Studies on this aspect were undertaken by Packard (1905), De Kerville (1907, Pearse (1911), Rabaud (1,923), Gabritschevsky (1927), Gerrsch (1939. sometimes ciliated. ...
The southern Africa species of the genera Misumena, Misumenops and Thomisus are revised. A diagnosis and new distribution records are provided for the genus
Runclnia in addition to the description of a new species. These genera belong to the Misumena-group of genera of the subfamily Misumeninae. Keys are provided to the subfamilies, genera and species. Biological and distributional data for all species
are given. Twenty-five spec sub-species are synonymized. Five species were recorded from this region for the first time.
... Según Silva-Moreira y Machado (2016) las variaciones de color no parecen seguir un patrón geográfico, y parecen estar relacionadas con el camuflaje en sus sitios de caza. Si bien es probable que esas arañas sean capaces de cambiar de color, como hacen otras tomisidas (Gabritschevsky 1927, Oxford y Gillespie 1998, todavía no hay ningún estudio que corrobore esta hipótesis. Estudios sobre la biología de Mantispinae en la región Neotropical son particularmente escasos (Trillo et al., 2105;Ohl, 2004). ...
Entanoneura batesella (Westwood, 1867) (Insecta: Neuroptera: Mantispidae) is reported for the first time as a predator to the egg sac of the crab spider Epicadus heterogaster (Guérin, 1829) (Arachnida: Araneae: Thomisidae). In Cerro Ñaju, Calzada Larga, Chilibre, Panama. Additionally, relevant ecological aspects of the parasitoid and its interaction with the host are mentioned.
Keywords: Predator, Neuroptera, crab spiders, Thomisidae, egg sacks.
... While some animal species change their body colour by exposing and concealing pigments in a very short time (e.g. Stuart-Fox & Moussalli, 2009), in crab spiders colour change takes from 2 days to 3 weeks, depending on the spider species, the direction of colour change and the experimental conditions (Angus, 1882;Gabritschevsky, 1927;Gadeau de Kerville, 1907;Llandres, Figon, Christid es, Mandon, & Casas, 2013;Schmalhofer, 2000). ...
Some crab spiders can change their colour to match the flower they use as a hunting platform and, in choice trials, they select same-colour flowers over contrasting flowers. Colour change is a costly physiological process that could help spiders capture more prey or avoid predators. There is no evidence, however, that crypsis increases the hunting success of spiders, and its effect on predator avoidance has not been studied. To evaluate the effect of crypsis on predation rate we tethered yellow crab spiders, Thomisus onustus, to artificial white and yellow flowers. To evaluate its effect on hunting success we released them on yellow corn daisy, Glebionis segetum, inflorescences and purple common mallow, Malva sylvestris, flowers. The colour contrast between crab spiders and artificial flowers was well above the detection threshold, but it was twice as large for spiders tethered to white flowers. Overall predation risk was higher on white than on yellow flowers. Yellow spiders released on purple mallows were three times more likely to capture prey than those released on yellow daisies. Despite this difference, during field surveys we have never seen a Thomisus female hunting on a mallow flower. Colour match plays a role in predator avoidance. Imperfect crypsis, that is, not matching a flower exactly, still more than halved predation rates on crab spiders and, in the field, spiders selected flowers with colours they could match, ignoring others where their hunting success would be much higher, but where they would be extremely conspicuous.
... Received 10 July 2018; Received in revised form 21 November 2018; Accepted 4 December 2018 camouflage on the flowers they use for hunting, hindering their detection by pollinators through cryptic coloration. Furthermore, crab spiders can select hunting sites that match their own body color (Chittka, 2001;Thery and Casas, 2002;Heiling et al. 2005aHeiling et al. , 2006, actively change their body color to match the color of the flowers (Gabritschevsky, 1927;Oxford and Gillespie, 1998;Morse, 2007), and even actively lure pollinators deceptively through uv-reflection (e.g., Heiling et al., 2003;Heiling et al., 2005b;Herberstein et al., 2009;Vieira et al., 2017). Such investment in behavioral and/or physiological strategies can also be accompanied by a careful selection of host plants, leading to high fidelity to particular foraging sites. ...
Flower‐dwelling predators make flowers dangerous foraging sites for pollinators, potentially affecting their anti‐predator behaviour. Moreover, predation vulnerability often varies among pollinators' body sizes with interspecific comparisons showing that smaller species are more vulnerable than larger ones. However, how intraspecific body size variation influences pollinator behaviour under predation risk is still unknown, especially under natural conditions.
We hypothesized that bumblebee workers of different sizes will exhibit different foraging strategies under predation risk. We predict that (a) small workers should more often exhibit anti‐predator behaviours than larger workers. We also hypothesized that the anti‐predator behaviour should be influenced by predator size and reward availability; therefore, we expect (b) higher avoidance behaviour towards larger predator sizes and (c) more and longer visits to inflorescences with high nectar availability. Finally, we expect that (d) nectar availability should overcome the anti‐predator behaviour in less vulnerable, large, workers.
We recorded flower visitation, time spent and rejection behaviours of different sizes of Bombus terrestris (Apidae) workers (large, medium and small) to inflorescences of Alstroemeria aurea (Alstroemeriaceae) with different treatments of artificial spiders (small and large) and nectar availability (with, without).
Anti‐predator and foraging behaviour of bumblebees was affected by the size of the worker, the presence of artificial spiders and nectar availability. Large and medium size bumblebees strongly reduced flower visitation and time spent in the presence of artificial spiders, consistently avoiding flowers with spiders, regardless of spider size or nectar availability. Instead, small bumblebees seldom modified their behaviour when facing artificial spiders, only increasing their avoidance or decreasing their foraging time in nectarless flowers hosting large artificial spiders.
This pattern of larger workers being more sensitive to predation risk than smaller ones at the intraspecific level in B. terrestris is contrary to the expected and acknowledged trend based on previous interspecific comparisons, but partially consistent with predictions of models of optimal foraging theory. Intraspecific behavioural variability was uncovered only when nectar was available, whereas artificial predator size rarely modified bumblebee anti‐predator and foraging behaviour. Therefore, our findings suggest that the trade‐off between maximizing resource intake and minimizing predation risk strongly varies across bumblebee worker body sizes.
... Received 10 July 2018; Received in revised form 21 November 2018; Accepted 4 December 2018 camouflage on the flowers they use for hunting, hindering their detection by pollinators through cryptic coloration. Furthermore, crab spiders can select hunting sites that match their own body color (Chittka, 2001;Thery and Casas, 2002;Heiling et al. 2005aHeiling et al. , 2006, actively change their body color to match the color of the flowers (Gabritschevsky, 1927;Oxford and Gillespie, 1998;Morse, 2007), and even actively lure pollinators deceptively through uv-reflection (e.g., Heiling et al., 2003;Heiling et al., 2005b;Herberstein et al., 2009;Vieira et al., 2017). Such investment in behavioral and/or physiological strategies can also be accompanied by a careful selection of host plants, leading to high fidelity to particular foraging sites. ...
Flower-dwelling predators may play several ecological roles depending on their effects on the reproductive success of the plants that they use to forage. However, tri-trophic interactions often are context-dependent highlighting the importance of assessing both the overall top-down effect on plant fitness and predator behavioral and physiological attributes that shape that outcome. We studied the effect of the flower-dwelling crab spider Misumenops pallidus on the perennial herb Anemone multifida in a low-thicket in Northwestern Patagonia. We measured pollinator visitation frequency, florivory rate, plant fitness, spider abundance, and spider's physiological (e.g. camouflage) and behavioral attributes (e.g. host selection, fidelity) that aid to define its possible ecological role. Misumenops pallidus showed a generalist diet (mostly pollinators), camouflage strategies, and intraspecific selection for plants bearing higher number and longer trichomes. Additionally, it displayed host-fidelity with long periods of permanence in the selected host plant, occupying ∼25% of plant population. However, the presence of these spiders did not affect pollinator visitation rate, florivory or plant fitness, indicating a commensalism role. Our findings suggested that the asymmetric benefit in this plant-spider association may be attributed to a combination of factors. In particular, the low-to-moderate spider abundance, generalist diet and cryptic camouflage; all of which weaken the top-down effect on pollinators and plant fitness, especially whenever ecological redundant pollinators are present. However, temporal and/or spatial variation on spider population might enhance this asymmetric benefit for the spider, potentially changing its role from commensalism to antagonism.
... Según Silva-Moreira y Machado (2016) las variaciones de color no parecen seguir un patrón geográfico, y parecen estar relacionadas con el camuflaje en sus sitios de caza. Si bien es probable que esas arañas sean capaces de cambiar de color, como hacen otras tomisidas (Gabritschevsky 1927, Oxford y Gillespie 1998, todavía no hay ningún estudio que corrobore esta hipótesis. Estudios sobre la biología de Mantispinae en la región Neotropical son particularmente escasos (Trillo et al., 2105;Ohl, 2004). ...
Entanoneura batesella (Westwood, 1867) (Insecta: Neuroptera: Mantispidae) is reported for the first time as a predator to the egg sac of the crab spider Epicadus heterogaster (Guérin, 1829) (Arachnida: Araneae: Thomisidae). In Cerro Ñaju, Calzada Larga, Chilibre, Panama. Additionally, relevant ecological aspects of the parasitoid and its interaction with the host are mentioned.
Keywords: Predator, Neuroptera, crab spiders, Thomisidae, egg sacks.
... The color variations do not seem to follow a geographical pattern, and they might be related to camouflage at their hunting sites. While it is likely that those spiders are capable of changing colors, as other thomisids do like Misumena vatia (Clerck, 1757) (see Gabritschevsky 1927, Oxford & Gillespie 1998, there is yet no study corroborating this hypothesis. Romero & Vasconcellos-Neto (2007) and Vasconcellos-Neto & Ramires (2007) made a series of ecological and behavioral observations on E. heterogaster. ...
All species of Epicadus Simon, 1895 are reviewed and redescribed, including the previously unknown males of E. rubripes
Mello-Leitão, 1924 and E. planus Mello-Leitão, 1932. A new diagnosis based on morphological characters is proposed
for the genus. Three valid species of Epicadus are recognized: E. heterogaster (Guérin-Méneville, 1829); E.
rubripes and E. planus. The following taxonomic changes are proposed: E. granulatus Banks, 1909 is considered incertae
sedis, most likely belonging to a new genus; E. h. scholagriculae Piza, 1933 is considered a junior subjective synonym of
E. heterogaster; E. pallidus Mello-Leitão, 1929 is considered a junior subjective synonym of E. rubripes Mello-Leitão,
1924; E. nigronotatus Mello-Leitão, 1940 is considered junior subjective synonym of E. planus Mello-Leitão, 1932. Species
distributions were updated with new records in the Neotropics, including Bolivia, Colombia, Ecuador, Mexico, Panama,
Paraguay, Peru and Venezuela, which makes Epicadus a genus of Neotropical distribution.
... It has thus been generally assumed that vision plays a role in the colour change of M. vatia. Indeed, several studies have not only revealed that reflected light from the substrate influences colour change (Gabritschevsky, 1927; Thé ry, 2007), but also that white spiders with black-painted eyes do not change their colour even when placed on a yellow background (Weigel, 1941). However, it has been observed that a white spider on a yellow substrate does not systematically change its colour (Thé ry and Casas, 2009; Defrize, personal observation), indicating that other factors may also drive the morphological colour change. ...
... Other pollinators, such as bumblebees, are also less likely to visit patches where crab spiders are present (Dukas and Morse 2003). Flower-dwelling thomisids are well recognised for their colourful appearance and their ability to reversibly change colour over several days (Gabritschevsky 1927; Oxford and Gillespie 1998; Schmalhofer 2000; Fig. 25.1). The best-studied models of colour change are M. vatia and Thomisus onustus. ...
Crab spiders are formidable predators of many insects. Their colour is particularly fascinating and we have an excellent account of the foraging ecology of some species. A more recent research focus has been the prevalence of UV reflection in some crab spider species. In this chapter we discuss the methods of quantifying colour and colour contrast and review the distribution, mechanism, function and evolution of UV reflectance amongst crab spiders. © 2013 Springer-Verlag Berlin Heidelberg. All rights are reserved.
... Both pigmentary and structural colours may be displayed statically, where the colour is 'on' for the whole life of an individual, or change reversibly. Those that take place over days to weeks are morphological colour changes (Gabritschevsky, 1927;Insausti & Casas, 2008). For example, in many birds, plumage colour changes upon the commencement of the mating season (Ralph, 1969). ...
Bright colouration in animals has long attracted the attention of physicists, chemists
and biologists. As such, studies on the functions of colours are interdisciplinary,
focusing on the mechanisms of colour production and maintenance, the
physical and chemical properties of the colour-producing elements, and visual
systems and behaviour of potential receivers. Blue colouration has received a large
share of research attention and is fascinating for several reasons: blue has been
attributed to a very broad range of functions, blue is achieved by a great variety of
mechanisms (although their production and maintenance costs are currently
unclear), and the blue part of the spectrum (450–490 nm) can be perceived by most
taxa. This review explores the breadth of studies that propose a function for blue
colouration. In so doing, it discusses the diversity of ways in which blue colours
are produced both as pigments and structural colours, and that blue visual pigments
are common across a broad range of taxa. This analysis of the current
literature emphasizes the importance of multidisciplinary hypothesis testing when
attempting to elucidate the function of colours, the need for manipulative over
correlative evidence for the function of colours, and, as colour research becomes
evermore interdisciplinary, the need for well-defined consistent terminology
... Particularly noteworthy are the reports of FRIEDRICH (1906) and those of OPPENHEIM (1908), whose results differed significantly from those described by BONNET. Autotomy, ordinary tomy and the capacity for regeneration in spiders were also the subject of study of many other arachnologists (GABRITSCHEVSKY, 1927(GABRITSCHEVSKY, , 1930LOCKET, 1936;SAVORY, 1936;MIKULSKA et al., 1975;RUHLAND, 1976;RANDAL, 1981;ROTH and ROTH, 1984;VOLLRATH, 1990), who observed interesting relationships between those processes. It turned out that some spiders, such as Araneus diadematus (CLERCK), Argiope argentata (FABRICIUS), Cyrtophora moluccensis (DOLESCHALL), Tegenaria atrica C.L.KOCH or Dolomedes fimbriatus (CLERCK), regenerate their appendages amputated at different places as successfully as those cut off at the articulations between the coxa and the trochanter. ...
Epimorphosis of Heterosymelic Appendages in Tegenaria Atrica (Araneae, Agelenidae)
Studies of epimorphic regeneration of appendages were carried out on larvae and nymphs of Tegenaria atrica C.L. Koch with heterosymely (accretion of appendages on the same side of the body) of two walking appendages and of walking appendages with pedipalpi. All the anomalies were obtained by exposing developing embryos to alternate temperatures of 14 and 32°C. Amputation of fragments of anomalous appendages was always followed by regeneration. Based on the characteristic external structures of the regenerating joints, successive stages of epimorphosis were estabilished, whose start and end were marked by ecdyses. Several types of regenerates were found, whose anatomical structure did not undergo further significant changes until the end of our observations.
... Other arachnologists who have studied the capability for appendage regeneration include Friedrich (1906), Weiss (1907), Oppenheim (1908, Wood (1926), Gabritschevsky (1927Gabritschevsky ( , 1930, Bonnet (1930), Locket (1936), Savory (1936), Ruhland (1976), Randall (1981, Roth & Roth (1984) and Vollrath (1990). According to these authors epimorphosis of the feeding and walking appendages of the prosoma is a common phenomenon, and as long as the spider is capable of moulting it can regenerate its lost appendages. ...
... Experiments concerning regeneration of appendages and related structures in various spider species have been conducted by arachnologists for many years (FRIEDRICH, 1906;WEISS, 1907;OPPENHEIM, 1908;WOOD, 1926;GABRITSCHEVSKY, 1927GABRITSCHEVSKY, , 1930BONNET, 1930;LOCKET, 1936;SAVORY, 1936;VACHON, 1967;RUHLAND, 1976;RANDALL, 1981;ROTH & ROTH, 1984;VOLLRATH, 1990). The problem has also been studied by MIKULSKA et al. (1975) andJACUÑSKI et al. (1994). ...
Postamputation regeneration of a bifurcate (schistomelic) fragment of a chelicera in a larva of Tegenaria atrica C.L.KOCH is described. Epimorphic processes resulted in the development of a normally structured mouth appendage in III stage nymph.
... The first remarkable reports concerning that problem were published by Friedrich (1906), Oppenheim (1908) and Weiss (1907). Many years later our knowledge of the subject of epimorphosis was enriched by information published by Wood (1926), Gabritschevsky (1927Gabritschevsky ( , 1930, Bonnet (1930), Locket (1936), Savory (1936), Randall (1981), Roth & Roth (1984) and Vollrath (1990). ...
Experimental studies of regeneration and repair processes of schistomelic walking legs and pedipalps in the early postembryonal
stages of Tegenaria atrica were carried out in two parts. In the first part changes in the structure of appendages were produced by exposing the developing
embryos to alternating temperatures (14 and 32�C, changing every 12 hours) as teratogenic factor. In the second, principal,
part of studies after amputating a given fragment of a larval schistomelic appendage the appearance, then the growth and development
of the external regenerates were observed. The completion of epimorphosis of the pedipalps followed at nymph IV stage (after
four post-larval moults) that of the walking appendages in most cases at nymph V stage (after five post-larval moults). In
control spiders repair processes were noted, which proceeded at a rate comparable to regeneration processes.
... More rapid changes in color pattern have been noted in spiders of the family Araneidae, which accumulate guanine beneath the cuticle during periods of starvation, thereby developing a pattern of opaque white blotches over the abdomen (Foelix 1979) . Reversible color change has been most extensively documented in the crab spider Misumena vatia (Clerck) (Packard 1905 ; Gadeau de Kerville 1907 ; Rabaud 1923 ; Gabritschevsky 1927 ; Weigel 1941 ; Hinton 1976) . This spider is usually whitish and sits on white flowers . ...
The Hawaiian happy-face spider Theridion grallator,Simon is a smalll spider, endemic to Hawaii, where it is found under leaves in the wet and mesic forests . The abdomen is pale, translucent yellow, but variable amounts of red, black or white pigment may be superimposed on this to generate a host of patterned morphs . The translucence of the abdomen may enhance crypsis against predators searching the underside of leaves ; the variability in the superimposed pattern may serve to counteract the development of a search image by the predator . The present study documents plasticity in base coloration, which can changee rapidly and markedly following ingestion of certain types of prey . This may be merely a consequence of abdominal translucence . But it is interesting to note that it adds a whole new dimension to the color polymorphism of the species .
... As predators of agricultural pests, thomisids play an important part in natural pest control (Riechert and Lockley, 1984; Nyffeler and Benz, 1987; Uetz et al., 1999). Some thomisids (e.g., Misumena, Diaea, Runcinia and Thomisus) possess the ability to change color and blend into their habitat, in most cases flowers (Packard, 1905; Gabritschevsky, 1927; Comstock, 1948). Misumena vatia (Clerck, 1757) has a remarkable ability to change color, which takes place during migration to flowers of different color from spring to the early part of summer (Comstock, 1948). ...
The first quantitative phylogenetic analysis of three sequenced genes (16S rRNA, cytochrome c oxidase subunit I, histone 3) of 25 genera of crab spiders and 11 outgroups supports the monophyly of Thomisidae. Four lineages within Thomisidae are recovered. They are informally named here as the Borboropactus clade, Epidius clade, Stephanopis clade and the Thomisus clade, pending detailed morphology based cladistic work. The Thomisus clade is recovered as a strongly supported monophyletic group with a minimal genetic divergence. Philodromidae previously widely considered a subfamily of Thomisidae do not group within thomisids and is excluded from Thomisidae. However, Aphantochilinae previously generally considered as a separate family falls within the Thomisus clade and is included in Thomisidae. The recently proposed new family Borboropactidae is rejected, as it is paraphyletic.
© The Willi Hennig Society 2008.
... It is difficult to interpret variation in pollinator response to crab spiders, because the colour signal produced by crab spiders is a plastic trait, and spiders change their colour over several days (Oxford & Gillespie, 1998). For example, Misumena vatia spiders turn from white to yellow in 10-25 days on artificially coloured backgrounds, and the reversed change can take 4-6 days (Gabritschevsky, 1927). Other studies have also reported similar colour changes for Misumenoides formosipes and Thomisus onustus crab spiders (Heckel, 1891;Gertsch, 1939). ...
1. Australian crab spiders exploit the plant–pollinator mutualism by reflecting UV light that attracts pollinators to the flowers where they sit. However, spider UV reflection seems to vary broadly within and between individuals and species, and we are still lacking any comparative studies of prey and/or predator behaviour towards spider colour variation.2. Here we looked at the natural variation in the coloration of two species of Australian crab spiders, Thomisus spectabilis and Diaea evanida, collected from the field. Furthermore, we examined how two species of native bees responded to variation in colour contrast generated by spiders sitting in flowers compared with vacant flowers. We used data from a bee choice experiment with D. evanida spiders and Trigona carbonaria bees and also published data on T. spectabilis spiders and Austroplebeia australis bees.3. In the field both spider species were always achromatically (from a distance) undetectable but chromatically (at closer range) detectable for bees. Experimentally, we showed species-specific differences in bee behaviour towards particular spider colour variation: T. carbonaria bees did not show any preference for any colour contrasts generated by D. evanida spiders but A. australis bees were more likely to reject flowers with more contrasting T. spectabilis spiders.4. Our study suggests that some of the spider colour variation that we encounter in the field may be partly explained by the spider's ability to adjust the reflectance properties of its colour relative to the behaviour of the species of prey available.
... Adult females of several crab spider species in the Thomisidae are able to change their colour between white and yellow (in rare cases also pink/purple). This ability has been studied for over one century and was claimed to have evolved as a strategy to minimize the colour contrast on inflorescences where they wait for flower visitors (Angus 1882; Rabaud 1919; Gabritschevsky 1927; Weigel 1941; Morse 1979 Morse , 1981 Morse , 2007 Schmalhofer 2001; Théry & Casas 2002; Heiling & Herberstein 2004; Théry 2007). The duration of colour change to adapt body colour reported in these studies ranges from 2 to 20 days with a mean of 4– 7 days; it is therefore a morphological colour change (Oxford & Gillespie 1998; Insausti & Casas 2008, in press). ...
Cryptic coloration is assumed to be beneficial to predators because of an increased encounter rate with unwary prey. This hypothesis is, however, very rarely, if ever, studied in the field. The aim of this study was to quantify the encounter rate and capture success of an ambush predator, in the field, as a function of its level of colour-matching with the background. We used the crab spider Misumena vatia, which varies its body colour and can thereby match the colour of the flower it hunts upon. We carried out a manipulative field experiment using a complete factorial design resulting in six different colour combinations of crab spiders and flowers differing in their degree of colour-matching. A rich and diverse set of naturally occurring insects visited the flowers while we continuously video-recorded the spider's foraging activity. This enabled us to test the crypsis, the spider avoidance and the flower visitor attraction hypotheses, all three supported by previous studies. Flower visitors of different groups either avoided crab spiders independent of colour-matching, such as solitary bees and syrphid flies, or ignored them, such as bumble-bees and honeybees. Moreover, colour-matched spiders did not have a higher encounter rate and capture success compared to the visually apparent ones. Thus, our results support the spider avoidance hypothesis, reject the two other hypotheses and uncovered a fourth behaviour: indifference to predators. Because flower visitors reacted differently, a community approach is mandatory in order to understand the function of background colour-matching in generalist predators. We discuss our results in relation to the size and sociality of the prey and in relation to the functional significance of colour change in this predator.
... Many crab spiders (Thomisidae) specialise in ambushing pollinators on flowers. In several species, adult females can change their body colour to match the colour of the flowers on which they sit [10,141516. Moreover, some studies report that crab spiders settled preferentially on flowers that matched their body colour: yellow crab spiders selected preferentially yellow flowers and white crab spiders tended to sit on white flowers to forage [17,18]. ...
According to the crypsis hypothesis, the ability of female crab spiders to change body colour and match the colour of flowers has been selected because flower visitors are less likely to detect spiders that match the colour of the flowers used as hunting platform. However, recent findings suggest that spider crypsis plays a minor role in predator detection and some studies even showed that pollinators can become attracted to flowers harbouring Australian crab spider when the UV contrast between spider and flower increases. Here we studied the response of Apis mellifera honeybees to the presence of white or yellow Thomisus spectabilis Australian crab spiders sitting on Bidens alba inflorescences and also the response of honeybees to crab spiders that we made easily detectable painting blue their forelimbs or abdomen. To account for the visual systems of crab spider's prey, we measured the reflectance properties of the spiders and inflorescences used for the experiments. We found that honeybees did not respond to the degree of matching between spiders and inflorescences (either chromatic or achromatic contrast): they responded similarly to white and yellow spiders, to control and painted spiders. However spider UV reflection, spider size and spider movement determined honeybee behaviour: the probability that honeybees landed on spider-harbouring inflorescences was greatest when the spiders were large and had high UV reflectance or when spiders were small and reflected little UV, and honeybees were more likely to reject inflorescences if spiders moved as the bee approached the inflorescence. Our study suggests that only the large, but not the small Australian crab spiders deceive their preys by reflecting UV light, and highlights the importance of other cues that elicited an anti-predator response in honeybees.
... It has thus been generally assumed that vision plays a role in the colour change of M. vatia. Indeed, several studies have not only revealed that reflected light from the substrate influences colour change (Gabritschevsky, 1927; Thé ry, 2007), but also that white spiders with black-painted eyes do not change their colour even when placed on a yellow background (Weigel, 1941). However, it has been observed that a white spider on a yellow substrate does not systematically change its colour (Thé ry and Casas, 2009; Defrize, personal observation), indicating that other factors may also drive the morphological colour change. ...
Vision plays a paramount role in some spider families such as the Salticidae, Lycosidae and Thomisidae, as it is involved in prey hunting, orientation or choice of substrate. In the thomisid Misumena vatia, for which the substrate colour affects the body colour, vision seems to mediate morphological colour changes. However, nothing is known about which component of visual signals from the substrate might be perceived, nor whether M. vatia possesses the physiological basis for colour vision. The aim of this study is thus to investigate the vision of this spider species by measuring the spectral sensitivities of the different pairs of eyes using electrophysiological methods. Extra- and intracellular electrophysiological recordings combined with selective adaptation revealed the presence of two classes of photoreceptor cells, one sensitive in the UV region of the spectrum (around 340 nm) and one sensitive in the green (around 520 nm) regions in the four pairs of eyes. We conclude that M. vatia possesses the physiological potential to perceive both chromatic and achromatic components of the environment.
... Ommochromes are end products of the tryptophan metabolism in arthropods, which are either excreted or stored until the death of the animal (Linzen, 1974;Needham, 1974). Female crab-spiders of the family Thomisidae are capable of changing their color reversibly in a few days, from white to yellow and back (Gabritchevsky, 1927;Weigel, 1941;Holl, 1987). In particular, the pigmentation of the species of Thomisus has been studied since the pioneering work by Heckel (1891). ...
Ommochromes are end products of the tryptophan metabolism in arthropods. While the anabolism of ommochromes has been well studied, the catabolism is totally unknown. In order to study it, we used the crab-spider Misumena vatia, which is able to change color reversibly in a few days, from yellow to white and back. Ommochromes is the only pigment class responsible for the body coloration in this animal. The aim of this study was to analyze the fine structure of the epidermal cells in bleaching spiders, in an attempt to correlate morphological changes with the fate of the pigment granules. Central to the process of bleaching is the lysis of the ommochrome granules. In the same cell, intact granules and granules in different degradation stages are found. The degradation begins with granule autolysis. Some components are extruded in the extracellular space and others are recycled via autophagy. Abundant glycogen appears associated to granulolysis. In a later stage of bleaching, ommochrome progranules, typical of white spiders, appear in the distal zone of the same epidermal cell. Catabolism and anabolism of pigment granules thus take place simultaneously in spider epidermal cells. A cyclic pathway of pigment granules formation and degradation, throughout a complete cycle of color change is proposed, together with an explanation for this turnover, involving photoprotection against UV by ommochromes metabolites. The presence of this turnover for melanins is discussed.
... The second hypothesis states that main raison d'e ˆtre of ommochromes is signalling, mimicry and crypsis. This is the hypothesis supported by most of the community working on colour changing insects such as stick insects and mantids (Fuzeau-Braesch 1985), including Mantis religiosa, Sphodromantis viridis and Locusta migratoria (Vuillaume 1968), and spiders (Rabaud 1918Rabaud , 1919 Gabritschevsky 1927; Schmalhofer 2000; Chittka 2001; Théry & Casas 2002; Heiling et al. 2003 Heiling et al. , 2005a Théry et al. 2005; Théry 2007). In order to test this hypothesis, we need to assess the fitness value of the camouflage and the fitness gain from a change of colour. ...
Diverse functions have been assigned to the visual appearance of webs, spiders and web decorations, including prey attraction, predator deterrence and camouflage. Here, we review the pertinent literature, focusing on potential camouflage and mimicry. Webs are often difficult to detect in a heterogeneous visual environment. Static and dynamic web distortions are used to escape visual detection by prey, although particular silk may also attract prey. Recent work using physiological models of vision taking into account visual environments rarely supports the hypothesis of spider camouflage by decorations, but most often the prey attraction and predator confusion hypotheses. Similarly, visual modelling shows that spider coloration is effective in attracting prey but not in conveying camouflage. Camouflage through colour change might be used by particular crab spiders to hide from predator or prey on flowers of different coloration. However, results obtained on a non-cryptic crab spider suggest that an alternative function of pigmentation may be to avoid UV photodamage through the transparent cuticle. Numerous species are clearly efficient locomotory mimics of ants, particularly in the eyes of their predators. We close our paper by highlighting gaps in our knowledge.
Spiders are often underestimated as suitable behavioural models because of the general belief that due to their small brains their behaviour is innate and mostly invariable. Challenging this assumption, this fascinating book shows that rather than having a limited behavioural repertoire, spiders show surprising cognitive abilities, changing their behaviour to suit their situational needs. The team of authors unravels the considerable intra-specific as well as intra-individual variability and plasticity in different behaviours ranging from foraging and web building to communication and courtship. An introductory chapter on spider biology, systematics and evolution provides the reader with the necessary background information to understand the discussed behaviours and helps to place them into an evolutionary context. Highlighting an under-explored area of behaviour, this book will provide new ideas for behavioural researchers and students unfamiliar with spiders as well as a valuable resource for those already working in this intriguing field.
Ultraviolet-visible (UV-Vis) reflectance spectroscopy is one of the useful tools to evaluate the coloration of materials and living things. On crab spiders, sit-and-wait foragers on flowers, body coloration has been focused in the context of camouflage and/or prey attraction. For the first time, the present study shows UV-Vis reflectance spectra of Thomisus labefactus, a crab spider inhabits East Asia, reflects UV-Vis rays almost the same strength as an Australian crab spider Thomisus spectabilis, which also has substantial amount of UV reflection, unlike European species lacking UV reflection.
紫外・可視（UV-Vis）反射分光法は，材料や生物の色彩を評価する有益なツールの一つである．カニグモは花の上で獲物を待ち伏せする捕食者であり，擬態および／あるいは餌誘引における文脈で，体の色彩に焦点が当てられてきた．本研究では，東アジアに生息するカニグモ科の一種であるアズチグモThomisus labefactusでは最初となるUV-Vis 反射スペクトルの測定から，紫外線反射を欠いているヨーロッパ産の種とは異なり，相当量の紫外線を反射するオーストラリア産のカニグモ科の一種Thomisus spectabilisと同程度の強さで紫外線と可視光を反射することが示される．
Pale lateral bands that contrast with somatic colouration are common to many semi-aquatic spider species and may contribute to camouflage. Dolomedes plantarius is dimorphic for the presence or absence of a broad, pale, lateral band on the abdomen and cephalothorax. Here, we investigate the heritability of this banding pattern by assessing the proportion of banded progeny in broods of spiderlings for which the phenotype of one or both parents was known. Our results indicate a single-gene system of inheritance with the banded allele dominant to the unbanded. This finding offers a simple way to investigate various aspects of the biology of this rare spider, which is classified as vulnerable to extinction. We consider the implications for further understanding the mating system of D. plantarius and for studying the function and maintenance of banding in wild populations.
Despite being widely known as a diverse group of predators, spiders are also a regular prey item of several vertebrate and invertebrate predators. Some of these organisms (e.g., wasp species and araneophagic spiders) are spider-hunting specialists. A number of morphological structures and behaviours in spiders have been proposed to be anti-predator adaptations. They comprise strategies such as background matching, disruptive patterns, web decorations, mimicry, masquerading, aposematism, urticating bristles, spines, retreats, barrier webs, group living, and dropping from webs. In this chapter, spider anti-predator strategies are presented, and the correlational and causal evidence of anti-predator adaptations are critically discussed in light of potential costs and benefits they may entail. Studies involving Neotropical species are presented to illustrate most strategies.
Gea (Araneae, Araneidae) is a tropical orb-weaving spider showing dark brown abdominal color with yellow and white patches and many smaller scattered yellowish and white spots on the dorsum. This study documents rapid and reversible physiological color change in Gea Spp. Ecological and behavioral studies pertaining to spiders are very few in India and such studies will shed more light on the ecophysiological mechanism and the possible evolutionary dimensions to the color change behavior observed in spiders.
Crab spiders (Thomisidae) are known by their ability to change their body colouration via change in epithelial pigments. However, the crab spider genus Stephanopis appears to match the colouration of the bark they are sitting on by having debris attached to its dorsal cuticle. The functional morphology, colouration, and evolution of this phenomenon were investigated in Stephanopis cf. scabra and S. cambridgei. Analysis under the microscope revealed that debris originated from the bark they were sitting on. Using scanning electron microscopy, three different types of setae likely related in the retention of debris were found in S. cf. scabra and one in S. cambridgei. These setae are branched and possess barbs, unlike the more filiform setae found in other crab spider species. In addition, the presence of debris improved the brightness background matching of spiders against the bark, but not hue and chroma matching. Ancestral character state reconstruction suggested that presence of debris evolved two to three times within Thomisidae. The evolution of both masking and colour change among crab spiders indicates that they are under a strong selection to avoid detection.
In the last decade, research on the previously dormant field of camouflage has advanced rapidly, with numerous studies challenging traditional concepts, investigating previously untested theories and incorporating a greater appreciation of the visual and cognitive systems of the observer. Using studies of both real animals and artificial systems, this book synthesises the current state of play in camouflage research and understanding. It introduces the different types of camouflage and how they work, including background matching, disruptive coloration and obliterative shading. It also demonstrates the methodologies used to study them and discusses how camouflage relates to other subjects, particularly with regard to what it can tell us about visual perception. The mixture of primary research and reviews shows students and researchers where the field currently stands and where exciting and important problems remain to be solved, illustrating how the study of camouflage is likely to progress in the future.
Belonging to a size category that makes them vulnerable to a wide variety of predators, spiders have evolved a bewildering array of anti-predator adaptations, which can be clustered under two broad categories, primary and secondary defence. Primary defences are ploys by which the spider avoids provoking pursuit by, and interaction with, the predator. Camouflage and masquerade are especially common examples. Secondary defences come into play once an interaction with a predator is under way, and these are the defences that have been most thoroughly studied. However, elements of anti-predator defence may often be integrated into other aspects of the spider's biology. Cues from predators may influence a spider's decision to move away from a habitat, and may also influence the decisions spiders make in the context of courtship, mating and oviposition. Anti-predator defences are sometimes subject to local adaptation by different populations within single species, and considerable flexibility in anti-predator ploys may be evident even at the level of the individual spider. Although vertebrates are often predators of spiders, anti-predator flexibility may have evolved primarily when the predator is another spider or an insect. Spider-spider encounters in particular have a way of blurring the distinction between anti-predator and predatory behaviour. Tremendous opportunity remains for research on the anti-predator defences of spiders, but perhaps the major challenge for future researchers will be to devise and carry out experiments that demonstrate the efficacy in the field of anti-predator defences that have thus far been studied primarily in the laboratory.
The higher-level phylogenetic relationships of crab spiders (Thomisidae) are studied from morphological data. 33 taxa are coded for 74 characters (53 binary and 21 multistate). Several analyses using equal, successive and implied weights were carried out. The most parsimonious tree obtained by analysis with successive and implied weights is put forward as the preferred hypothesis of thomisid relationships (length 222 steps, CI 0.74, RI 0.83). Thomisidae emerge monophyletic in all analyses, supported by four unambiguous synapomorphies. It is now apparent that thomisid taxa have been mostly defined on the basis of plesiomorphic character states. A number of taxonomic changes, including the description of new taxa are proposed and the evolution of diverse behaviors of thomisids is studied in light of the new phylogenetic result. Color change behavior evolved once within the family, but eye arrangement patterns of the median ocular quadrangle, thought to be diagnostic for many genera, evolved as much as 10 times independently. The following new species are described: Borboropactus nyerere sp. nov.,Cebrenninus srivijaya sp. nov., Geraesta lehtineni sp. nov. and Geraesta mkwawa sp. nov. The following new generic synonymies are proposed: Bucranium O. P.-Cambridge, 1881 = Aphantochilus O. P.-Cambridge, 1870; Sanmenia Song and Kim, 1992 = Pharta Thorell, 1891 and Cupa Strand, 1906 = Epidius Thorell, 1877. The following species are synonymized: Regillus divergens Hogg, 1914 and Borboropactus hainanus Song, 1993 = Borboropactus bituberculatus Simon, 1884 syn. nov., Epidius ganxiensis (Yin, Peng & Kim, 1999) = Epidius rubropictus Simon, 1909 syn. nov., Geraesta bilobata Simon, 1897 = Geraesta hirta Simon, 1889 syn. nov., Sanmenia kohi Ono, 1995 = Pharta bimaculata Thorell, 1891 syn. nov. and Sanmenia zhengi (Ono & Song, 1986) = Pharta brevipalpus (Simon, 1903) syn. nov. The following new combinations are proposed: Aphantochilus taurifrons (O. P.-Cambridge, 1881) comb. nov., Epidius typicus (Bösenberg & Strand, 1906) comb. nov., Pharta brevipalpus (Simon, 1903) comb. nov., Pharta gongshan (Yang, Zhu and Song, 2006) comb. nov., Pharta nigra (Tang, Griswold & Peng, 2009) comb. nov. and Pharta tengchong (Tang, Griswold & Yin, 2009) comb. nov.
In certain arthropod groups, including spiders, males seeking copulations may expose themselves to cannibalism from females that are larger and stronger than they are. Although old males are commonly believed to be particularly vulnerable to sexual cannibalism, virtually no data exist to back that supposition. Female crab spiders Misumena vatia (Thomisidae) regularly attacked prospective mates experimentally presented in pairs whose individuals differed in age. They usually attacked the older male; all but one of the seven males cannibalized in these encounters was the older member of the pair. These attacks paralleled a decline in numbers of field-observed males, probably a consequence of their increasing vulnerability. The females' responses appeared to result from differences in male behavior or condition, since virgin females, wild-captured adult (and probably previously mated) females and penultimate females all attacked males with similar frequency.
The Green lynx spider, Peucetia viridans, is normally coloured a uniform green. An individual heavily suffused with reddish pigment was collected from a reddish flower. Origin of the ability to match the colour of a non-native flower is discussed in relation to a recent study on spider colouration.
Sexual size dimorphism is often a likely outcome of the interplay between natural selection and sexual selection, with female size dictated primarily by natural selection that maximizes fecundity and male size by sexual selection that maximizes reproductive opportunities. Attention to male fitness has focused heavily on direct male-male conflict selecting for superior male size and/or fighting ability, although male reproductive traits vary immensely among animals. An alternative, advanced by Michael Ghiselin, posits highly mobile dwarf males as a strategy for finding relatively immobile females in low-density populations. Adult male crab spiders Misumena vatia, sit-and-wait predators, are strikingly smaller, much more active, and relatively longer-legged than their females. This size difference results largely from males having two fewer instars than females, which simultaneously results in marked protandry. Populations of M. vatia often were small and of low density, with a female-biased sex ratio and an operational sex ratio that changed strikingly over the season. Sexual selection through scramble competition (locating the female first) should favour this suite of characters in males of low-density populations. Although direct male-male contests favoured large males, the low densities of adult males and the dispersed, relatively immobile females led to low levels of direct intrasexual contest. Females exaggerated the problem of males in finding them by providing few cues to their presence, a pattern consistent with indirect mate choice. In addition to favouring high mobility, scramble competition favoured males that selected flowers attracting many prey, the sites most often occupied by females.
The female of the crab-spider, Misumena vatia, is one of the few spiders known to be able to change its colour reversibly. Adult females usually have red patches on each side of the abdomen. The most likely insect enemies of Misumena are red-blind, and because the red patches absorb ultraviolet exactly as does the rest of the abdomen the patches are not distinguishable to insects in the ultraviolet. It is suggested that the red patches function as a warning colour for birds and other vertebrates, which are not red-blind.
The life cycle of the spider Thomisus onustus , with its two adult phases annually, is elucidated. Differences between males and females, in the length of the developmental period up to maturity, excluded the possibility that siblings could mate in nature. Females maintain a stable cycle of one year, whereas the males show a change in the length of their developmental cycle, according to the phase from which they originate. The variance which occurs among spiderlings, in regard to the number of moults and the length of the different instars is discussed.
Outlines for a general classification of the life histories of spiders is being suggested.
This chapter aims at a broad exploration of the literature pertinent to the subject of spider camouflage, from web colour and decorations, body colour to movement. It is an extended and updated version of a previous paper (Théry & Casas 2009). Several functions have been assigned to spider web decorations, the most extensively studied being visually related, like camouflage from predator and/or prey, prey attraction and signalling to animals that are likely to damage the web (Herberstein et al. 2000; Bruce 2006). The function of these structures is highly controversial, as also are other visual aspects of spider ecology, like the appearance of spiders themselves. Moreover, a few spider species have the ability to change their body coloration, a peculiarity that has been suggested to improve camouflage or to constitute a form of aggressive mimicry (Oxford & Gillespie 1998). Are such visual appearances used to lure prey, deter predators or hide from predators or prey?
In males that compete aggressively for females, size and age may determine which males obtain access to these females. In the present study, we use the crab spider, Misumena vatia, a species with males that do not grow after becoming sexually mature adults, to test the hypothesis that age affects the success of males competing for access to females. M. vatia is an excellent species to test this hypothesis because it is possible to disentangle age from size, characters that typically vary together in the species usually tested. We staged encounters between similar-sized older and younger adult male M. vatia in the presence of a female to determine the role of age in male access to females. Encounters between the males occurred during 63.3% of these pairings. Younger males won significantly more (70.2%) of the encounters than did older ones, but did not initiate significantly more encounters than did older ones (62.5%). Although older males won only 29.8% of these encounters, they initiated significantly more (76.5%) of them than predicted by chance. This design also allowed us to test Parker's hypothesis that older individuals should exhibit a higher level of aggression than younger ones. However, attacks by younger males were most likely to include extensive bodily contact, whereas attacks by older males involved significantly less contact. These results counter the frequent assertion that older individuals usually prevail over younger ones in contests for access to females, and that older males are more likely to engage in highly overt aggression than are younger ones. Aging may decrease reproductive opportunities and success rates of male M. vatia, affecting as many as nearly one-fourth of their encounters. Copyright 2004.
The inactivation of a replication protein causes the disassembly of the replication machinery and creates a need for replication reactivation. In several replication mutants, restart occurs after the fork has been isomerized into a four-armed junction, a reaction called replication fork reversal. The repair helicase UvrD is essential for replication fork reversal upon inactivation of the polymerase (DnaE) or the beta-clamp (DnaN) subunits of the Escherichia coli polymerase III, and for the viability of dnaEts and dnaNts mutants at semi-permissive temperature. We show here that the inactivation of recA, recFOR, recJ or recQ recombination genes suppresses the requirement for UvrD for replication fork reversal and suppresses the lethality conferred by uvrD inactivation to Pol IIIts mutants at semi-permissive temperature. We propose that RecA binds inappropriately to blocked replication forks in the dnaEts and dnaNts mutants in a RecQ- RecJ- RecFOR-dependent way and that UvrD acts by removing RecA or a RecA-made structure, allowing replication fork reversal. This work thus reveals the existence of a futile reaction of RecA binding to blocked replication forks, that requires the action of UvrD for fork-clearing and proper replication restart.
Bull. Soc. Ent. d. France
- C. Gadeau der Kerville
Anpassungsfarben bei Krabspinnen
- Dahl F.
Change of color and protective coloration in Misumena vatia
- Packard A.
Note sommaire sur l'adaptation chromatique des Thomisides
- Rabaud E.
1889 1890 1893Book on spiders I II III
- J Mccook
Recherches sur la variation chromatique et l'homochromie des Arthropodes terrestres
- Rabaud E.