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Effects of temperature on sound production in the painted goby Pomatoschistus pictus
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December 2015
... marmoratus was separated geographically into two populations, Lindström & Lugli, 2000;Lugli et al., 1995Lugli et al., , 1997Lugli & Torricelli, 1999), from Portuguese marine/brackish waters (Amorim et al., , 2018Bolgan et al., 2013) or the west coast of Sweden . and it is well known that the ambient water temperature affects fish acoustic signals (Ladich, 2018;Vicente et al., 2015), we conducted two separate multivariate analyses: the first involving the complete dataset (all five acoustic features for each species), and the second excluding the temporal features (DUR and PRR) known to be influenced by water temperature (Lugli et al., 1996;Vicente et al., 2015). ...
... marmoratus was separated geographically into two populations, Lindström & Lugli, 2000;Lugli et al., 1995Lugli et al., , 1997Lugli & Torricelli, 1999), from Portuguese marine/brackish waters (Amorim et al., , 2018Bolgan et al., 2013) or the west coast of Sweden . and it is well known that the ambient water temperature affects fish acoustic signals (Ladich, 2018;Vicente et al., 2015), we conducted two separate multivariate analyses: the first involving the complete dataset (all five acoustic features for each species), and the second excluding the temporal features (DUR and PRR) known to be influenced by water temperature (Lugli et al., 1996;Vicente et al., 2015). ...
... Despite the small sample size, PD and PP differed significantly among males. In pulsed acoustic signals, PD can be related to body size and condition (Amorim et al., 2010) or temperature (Bennett, 1985;Vicente et al., 2015), ...
The Neretva dwarf goby Orsinigobius croaticus (Gobiiformes, Gobionellidae) is an en-demic fish native to the freshwaters of the Adriatic Basin in Croatia and Bosnia and Herzegovina, a Mediterranean Biodiversity Hotspot. Due to its limited distribution range, specific karst habitat and endangered status, laboratory studies on reproductive biology are scarce but crucial. Herein, we investigated the sound production and acoustic behaviour of the endangered O. croaticus during reproductive intersexual laboratory encounters, utilising an interdisciplinary approach. We also performed dis-sections and micro-computed tomography (μCT) scanning of the pectoral girdle to explore its potential involvement in sound production. Finally, comparative acoustic analysis was conducted on sounds produced by previously recorded soniferous sand gobies to investigate whether acoustic features are species-specific. The endemic O. croaticus is a soniferous species. Males of this species emit pulsatile sounds composed of a variable number of short (~15 ms) consecutive pulses when interacting with females, usually during the pre-spawning phase in the nest, but also during courtship outside the nest. Pulsatile sounds were low-frequency and short pulse trains (~140 Hz, <1000 ms). Male visual behaviour rate was higher when co-occurring with sounds and females entered the male's nest significantly more frequently when sounds were present. Characteristic body movements accompanied male sound production, such as head thrust and fin spreading. Furthermore, μCT scans and dissections suggest that O. croaticus shares certain anatomical similarities of the pectoral girdle (i.e. osseous elements and arrangement of levator pectoralis muscles) to previously studied sand gobies that could be involved in sound production. Multivariate comparisons, using sounds produced by eight soniferous European sand gobies, effectively distinguished soniferous (and sympatric) species based on their acoustic properties. However, the discrimination success decreased when temperature-dependent features (sound duration and pulse repetition rate) were excluded from the analysis. Therefore, we suggest both spectral and temporal features are important for the acoustic differentiation of sand gobies.
... Temperature effects are known on both peripheral and central mechanisms of signal production and detection, as well as on behaviour (Warren et al., 2017;Ladich, 2018). Previous studies have reported changes on temporal and spectral features of fish sounds associated with temperature (Torricelli et al., 1990;Lugli et al., 1996;Vicente et al., 2015). Acoustic features, such as sound duration, pulse period (PP) (duration between peak-to-peak interval of consecutive pulses, ms) or pulse repetition rate, sound amplitude, and spectral characteristics, have been reported to change with temperature (e.g., Connaughton et al., 2000), but the effect may depend on species (Ladich, 2018). ...
... Each male was used in a single tested temperature. Recordings were carried out from April to July 2022; the experimental protocol followed Amorim et al. (2013) and Vicente et al. (2015). In each recording day, we tested fish from the three temperature treatments, to exclude the influence of different breeding conditions throughout the 3month period of experiments. ...
... In fish species in which one contraction of the sonic muscles results in a sound pulse, increasing water temperature, and therefore body temperature, will result in a sound with a higher pulse rate due to its effect on the hindbrain central pattern generators controlling the activity of sonic muscles and on sonic muscle contraction speed (Bass et al., 2015). This is typically the case of drumming sounds resulting from the fast contraction of muscles acting on the swim bladder (e.g., Connaughton et al., 2000) but is also observable in drums produced by pectoral sonic muscles in gobies (Torricelli et al., 1990;Parmentier et al., 2013;Vicente et al., 2015;Parmentier et al., 2017). Indeed, in the closely related painted goby (P. ...
Acoustic signals in teleost fishes play a fundamental role in reproduction. As fish are ectothermic animals, temperature has the potential to change their signal production and detection, with further implications for mating interactions. In this study, we describe the mating sounds made by the two-spotted goby, Pomatoschistus flavescens, for the first time and further investigate the effect of temperature on the acoustic features. Courtship sounds of 15 two-spotted goby males were recorded at three different temperatures: 16 °C, 19 °C, and 21 °C. As seen for other marine gobies, two-spotted goby produced two courtship sounds: drums and thumps. Drums showed similar acoustic features to other Pomatoschistus species already studied. Calling rates for both kinds of sound were not affected by the increases in temperature. However, pulse rate increased from 16 °C to 19 °C and stabilised between 19 °C and 21 °C, suggesting that two-spotted gobies reached their physiological limits at 19 °C. Spectral features were also affected by temperature, presenting higher values at 19 °C. Whether or not the observed changes in acoustic features with temperature lead to changes in mating remains to be addressed. Studies like the present one are fundamental to better comprehend how reproduction will be affected by global warming in soniferous fishes.
... Temperature may influence visual courtship behaviour through its effect on general activity (Wilson, 2005;Bartolini et al., 2015) and affect acoustic communication through changes in central and peripheral processes of signal production and reception (Ladich, 2018). For example, the painted goby (Pomatoschistus pictus) produces pulsed courtship sounds called drums whose pulse period is linearly related with temperature (Vicente et al., 2015). Also, the Padanian goby (Padogobius bonelli) and the Arnogoby (Padogobius nigricans) produce tonal courtship sounds that are similarly influenced by temperature, showing a decrease in burst period of 1ms per degree Celsius (Lugli et al., 1997;Torricelli et al., 1990). ...
... 1V/μPa) was inserted in the chimney of the artificial nests during experiments to maximize the signal to noise ratio (SNR) of the fish sound recordings since two-spotted goby males often produce sounds at the entrance of their nests (de Jong et al., 2018a). Experimental aquaria were also placed on top of two 3 cm thick marble slabs interspaced with two levels of rubber foam shock absorbers, which significantly minimized the conduction of floor born vibrations Vicente et al., 2015). Another hydrophone (High Tech 94 SSQ, sensitivity of -165 dB re. ...
... However, within the mating season, studies report mixed results with either a positive effect of temperature on mating calling activity or no effect (Ladich, 2018). For example, similarly to the present study, Vicente et al. (2015) found that male calling rate (either drums or thumps) was not related with temperature in the closely related painted goby. In contrast, in some sciaenid and batrachoidid species, calling activity increases with temperature within the species-specific temperature range such as in wild and captive spotted sea trout (Montie et al., 2015;, in wild meagre (Vieira et al., 2022), and in wild Lusitanian toadfish (Amorim et al., 2006). ...
... The painted goby (Pomatoschistus pictus, Gobiidae) emits drum sounds during courtship. Again, the drum emission rate is not related to temperature (14-22°C) according to Vicente, Fonseca, and Amorim (2015). These studies in non-related taxa-namely the gurnard, cod and goby-reveal that the lack of a correlation does not depend on a particular behavioural context but likely on seasonal and daily patterns of foraging or reproductive behaviour. ...
... Parmentier (2012) (Table 3). In the croaking gourami, the dominant (peak) frequencies increases with temperature ( Figure 3), but no such effect was observed in the painted goby (Vicente et al., 2015). ...
... While many studies revealed a relationship between calling activity/sound characteristics and temperature, several studies failed to report such a relationship (cod- Brawn, 1961; oys- Maruska & Sisneros, 2015). A correlation between calling activity and temperature is furthermore lacking in representatives of gobiids and triglids (Amorim, 2005;Vicente et al., 2015). In the painted goby, temperature does not affect the drum emission rate, but there is a clear decrease in sound duration and PP at higher temperatures (Vicente et al., 2015). ...
Temperature affects peripheral and central mechanisms of signal production and detection in ectothermic animals. This study reviews for the first time the effects of temperature on acoustic communication in fishes and analyses whether changes in sound properties are coupled to changes in auditory sensitivities. Effects of temperature on sound production have been studied in approximately one dozen families of teleosts. Calling activity increased or was unaffected by temperature, in the latter case probably because seasonal, daily and lunar rhythms also influence mating behaviour and calling. Sound characteristics (pulse repetition rate, fundamental frequency) are positively correlated with temperature if pulses are directly based on sonic muscle contractions. In fishes possessing other sonic mechanisms, the dominant frequency of their pulsatile pectoral sounds may increase as well. Auditory sensitivities were mainly determined in otophysines, which possess enhanced hearing abilities. Studies revealed that hearing increased with temperature, in particular at higher frequencies. We know close to nothing about whether temperature-dependent changes in sound characteristics are coupled to changes in auditory sensitivity or mate choice. Female midshipman toadfish appear to choose males based on call frequency, which varies with temperature. Future studies need to address several topics: (i) temperature effects on sound production have to be separated from other sources of variation; (ii) effects on hearing need to be studied in many more taxa; (iii) potential negative effects of global warming on acoustic communication (because of temperature coupling) need to be investigated because fish constitute a major source of protein for humans.
... The painted goby (Pomatoschistus pictus, Gobiidae) emits drum sounds during courtship. Again, the drum emission rate is not related to temperature (14-22°C) according to Vicente, Fonseca, and Amorim (2015). These studies in non-related taxa-namely the gurnard, cod and goby-reveal that the lack of a correlation does not depend on a particular behavioural context but likely on seasonal and daily patterns of foraging or reproductive behaviour. ...
... Parmentier (2012) (Table 3). In the croaking gourami, the dominant (peak) frequencies increases with temperature ( Figure 3), but no such effect was observed in the painted goby (Vicente et al., 2015). ...
... While many studies revealed a relationship between calling activity/sound characteristics and temperature, several studies failed to report such a relationship (cod- Brawn, 1961; oys- Maruska & Sisneros, 2015). A correlation between calling activity and temperature is furthermore lacking in representatives of gobiids and triglids (Amorim, 2005;Vicente et al., 2015). In the painted goby, temperature does not affect the drum emission rate, but there is a clear decrease in sound duration and PP at higher temperatures (Vicente et al., 2015). ...
Ambient temperature affects peripheral and central mechanisms of signal production and detection in ectothermic animals. The effects of temperature on sound production have been investigated in representatives of at least 8 families of teleosts, namely, piranhas, thorny catfishes, toadfishes, gurnards, sculpins, gobies, croakers, and gouramis, mostly under laboratory conditions. Temperature affects calling behaviour and characteristics of vocalizations, but only a few general trends are evident. Calling activity may increase with rising temperature (toadfish, sculpins, catfish), or may not be affected (triglids) or even drop (toadfish), indicating that behavioral contexts and seasonal factors other than temperature influence activity. Temperature affects sound duration differently in different species. In contrast, pulse period usually decreases and the fundamental frequency of drumming sounds therefore increases as temperature rises. The dominant frequency increases as well, whereas sound pressure level may increase or remain unaffected. Studies in otophysines (cyprinids, catfishes) showed that auditory sensitivities increase at higher temperature in both eurythermal (temperate zone) and stenothermal (tropical) species. Sensitivities typically increased with higher frequencies by maximally 10 dB with one exception (36 dB, ictalurid catfish). A temperature-dependent sensitivity was described in toadfishes during the breeding season and, together with hormonal changes, presumably influences the attraction to conspecific calls.
... In recent years, however, there has been a rapid growth of interest in the fitness consequences of changes in temperature in a number of aquatic organisms, especially fish (e.g. personality traits in Pomacentrus moluccensis [18], risk assessment in Pomacentrus chrysurus [27], escape ability in Daphnia [28], stability of social hierarchy in Apistogramma agassizii [29], acoustic communication in Pomatoschistus pictus [30], and Trichopsis vittata [31]). ...
... Juvenile pompano, Trachinotus carolinus, exposed to controlled temperature increase showed frantic activity and behavior, and divulged a generalized physiological disorganization [19]. Also, Vicente et al. [30] observed that water temperature influenced pulse period -decreased by 1.95 ms per 1 °C and varied from 34 ms to 18.6 ms within the temperature range of 14-22 °C in the painted goby (Pomatoschistus pictus). ...
... They also found the effect on duration of mating sounds in the fish [30]. All of these studies showed negative effects of increased water temperatures on animal performances. ...
Temperature has profound effects on physiology of ectothermic animals. However, the effects on temperature variation on behavioral traits are poorly studied in contrast to physiological endpoints. This may be important as even small differences in temperatures have large effects on physiological rates including overall metabolism, and behavior is known to be linked to metabolism at least in part. The primary aim of this study was to determine the effects of ambient temperature on boldness responses of a species of fish commonly used in behavioral experiments, the Siamese fighting fish (Betta splendens). At 26°C, subjects were first examined for baseline behaviors over three days, using three different (but complementary) ‘open field’ type assays tested in a fixed order. Those same fish were next exposed to either the same temperature (26 °C) or a higher temperature (30 °C) for 10 days, and then the same behavioral assays were repeated. Those individuals exposed to increased temperatures reduced their latency to leave the release area (area I), spent more time in area III (farthest from release area), and were more active overall; together we infer these behaviors to reflect an increase in general ‘boldness’ with increased temperature. Our results add to a limited number of studies of temperature effects on behavioral tendencies in ectotherms that are evident even after some considerable acclimation. From a methodological perspective, our results indicate careful temperature control is needed when studying behavior in this and other species of fish.
... This is particularly the case in swim bladder drumming sounds generated by fast contractions of drumming muscles (Fine, 1978;Ladich, 1997;Connaughton et al., 2000;Amorim et al., 2006). The situation is very similar in gobies (Gobiidae), even though sounds are produced by a pectoral sonic muscle (Torricelli et al., 1990;Vicente et al., 2015;Parmentier et al., 2013Parmentier et al., , 2017. Generally, the drumming muscle contraction rate (pulse repetition rate, fundamental frequency) of drumming sounds increases with temperature. ...
... In the lab, for example, an increase in calling activity with temperature was described in the gudgeon Gobio gobio (Cyprinidae), the Jarbua terapon Terapon jarbua (Terapontidae), the bullhead Cottus gobio (Cottidae) and the red drum Sciaenops ocellatus (Sciaenidae) during seasonal light regimes or 12 h:12 h light cycles (Schneider, 1964;Ladich, 1988Ladich, , 1989Montie et al., 2016). In contrast, no such temperature effects were observed in the painted goby Pomatoschistus pictus (Gobiidae), the grey gurnard Eutrigla gurnardus (Triglidae) and the Atlantic cod Gadus morhua (Gadidae) (Brawn, 1961;Amorim, 2005;Vicente et al., 2015). ...
Sound communication is affected by ambient temperature in ectothermic animals including fishes. The present study examines the effects of temperature on acoustic signaling in a fish species possessing two different sound-generating mechanisms. The Amazonian Pictus catfish Pimelodus pictus produces low-frequency harmonic sounds (swimbladder drumming muscles) and high-frequency stridulation sounds (rubbing pectoral fin spines in the pectoral girdle). Sounds of 15 juveniles were recorded when hand-held after three weeks of acclimation at 30 °C, 22 °C and again 30 °C. The following sound characteristics were investigated: calling activity, sound duration, fundamental frequency of drumming sounds and dominant frequency of stridulation sounds. The number of both sound types produced within the first minute of experiments did not change with temperature. In contrast, sound duration was significantly shorter at 30 °C than at 22 °C (drumming: 78-560 ms; stridulation: 23-96 ms). The fundamental frequency of drumming sounds and thus the drumming muscle contraction rate varied from 127 Hz to 242 Hz and increased with temperature. The dominant frequency of broadband stridulation sounds ranged from 1.67 kHz to 3.39 kHz and was unaffected by temperature changes. Our data demonstrate that temperature affects acoustic signaling in P. pictus, although the changes differed between sound characteristics and sound type. The effects vary from no change in calling activity and dominant frequency, to an increase in fundamental frequency and shortened duration of both sound types. Together with the known effects of temperature on hearing in the Pictus cat, the present results indicate that global warming may affect acoustic communication in fishes.
... This preprint research paper has not been peer reviewed. Electronic copy available at: https://ssrn.com/abstract=4891293Vicente et al. 2015). As there seems to be no relationship between pulse rate and 386peak frequency in these species, it suggests that the sound's main energy is influenced by the ...
... For example, when there is a direct relation between sonic muscle contraction and sound pulses, pulse repetition rate (and fundamental frequency) is positively correlated with temperature (Ladich, 2018). This is the case of the painted goby in which the pulse repetition rate of mating drums increases 2.9 Hz on average per C (Vicente et al., 2015). Other features, like sound dominant frequency or calling rate, may also vary with temperature in different species (Ladich, 2018). ...
This paper outlines my research path over three decades while providing a review on the role of fish sounds in mate choice and reproduction. It also intends to provide advice to young scientists and point toward future avenues in this field of research. An overview of studies on different fish model species shows that male mating acoustic signals can inform females and male competitors about their size (dominant frequency, amplitude, and sound pulse rate modulation), body condition (calling activity and sound pulse rate), and readiness to mate (calling rate, number of pulses in a sound). At least in species with parental care, such as toadfishes, gobies, and pomacentrids, calling activity seems to be the main driver of reproductive success. Playback experiments ran on a restricted number of species consistently revealed that females prefer vocal to silent males and select for higher calling rates. This personal synthesis concludes with the suggestion to increase knowledge on fish mating signals, especially considering the emerging use of fish sounds to monitor aquatic environments due to increasing threats, like noise pollution.
... Because most fishes are ectotherms, the capability and speed of metabolic and physiological processes are influenced by the surrounding water temperature. Sound characteristics are expected to change with temperature, since it influences muscle contraction properties [60][61][62]. Generally, rising temperatures increase muscle contraction velocity and shorten muscle twitches, allowing the accommodation of a faster rate of pulse/call emissions that may be caused by faster oscillations of the Central Pattern Generator neural network [63]. ...
Many species rely on acoustic communication to fulfil several functions such as advertisement and mediation of social interactions (e.g., agonistic, mating). Therefore, fish calls can be an important source of information, e.g., to recognize reproductive periods or to assess fish welfare, and should be considered a potential non-intrusive tool in aquaculture management. Assessing fish acoustic activity, however, often requires long sound recordings. To analyse these long recordings automatic methods are invaluable tools to detect and extract the relevant biological information. Here we present a study to characterize meagre (Argyrosomus regius) acoustic activity during social contexts in captivity using an automatic pattern-recognition methodology based on the Hidden Markov Model. Calls produced by meagre during the breading season showed a richer repertoire than previously reported. Besides the dense choruses composed by grunts already known for this species, meagre emitted successive series of isolated pulses, audible as ‘knocks’. Grunts with a variable number of pulses were also registered. The overall acoustic activity was concurrent with the number of spawning events. A diel call rhythms exhibit peak of calling activity from 15:00 to midnight. In addition, grunt acoustic parameters varied significantly along the reproduction season. These results open the possibility to use the meagre vocal activity to predict breeding and approaching spawning periods in aquaculture management.
... 1758) (Spinks et al., 2017). Pulse rate is likely be very important in mate choice and conspecific recognition in fish (Vicente et al., 2015), therefore future studies are needed to understand if changes in pulse rate are coupled with changes in mate preference as found in insects (Conrad et al., 2017) and anurans (Baugh & Ryan, 2009;Castellano & Giacoma, 1998). ...
Underwater sound is directional and can convey important information about the surrounding environment or the animal emitting the sound. Therefore, sound is a major sensory channel for fishes and plays a key role in many life‐history strategies. The effect of anthropogenic noise on aquatic life, which may be causing homogenisation or fragmentation of biologically important signals underwater is of growing concern. In this review we discuss the role sound plays in the ecology of fishes, basic anatomical and physiological adaptations for sound reception and production, the effects of anthropogenic noise and how fishes may be coping to changes in their environment, to put the ecology of fish hearing into the context of the modern underwater soundscape.
... Temperature, for example, is an abiotic attribute of the environment that can influence both the form of a signal as well as the receiver's response. Temperature influences signaling in crickets (Martin et al., 2000), fireflies (Michaelidis et al., 2006), fish (Ladich and Schleinzer, 2015;Vicente et al., 2015) and bats (Camaclang et al., 2006), among others. ...
Although humans may have more nuanced reasons for communicating - e.g. to teach or inform, to share or change opinions or attitudes - all animals engage in communication with members of their own as well as other species, and there are more similarities than differences between non-human and human communication. All communication systems are composed of the same basic elements and all face comparable challenges. In this Commentary, we explore the extent to which research investigating how non-human animals communicate with each other (animal communication) overlaps in questions and approaches with research focused on how humans communicate with each other. We place a special focus on human communication involving scientific content, i.e. science communication. We begin with a brief review of the fields of animal communication and science communication. We next synthesize literature from each field to examine the roles, impacts and potential interactions of communication system elements - signaling environments, signalers, signal form and receivers - on effective communication. We find that research examining animal and human communication, including science communication, often has different emphases. Animal communication research, for example, tends to focus more on the role of the signaling environment through quantification of receiver responses. In contrast, science communication research currently emphasizes relationship building between signalers and receivers, and quantifies aspects of the receiver's psychology. Informed by our cross-disciplinary assessment, we propose potentially productive avenues of future research in both animal communication and science communication.
... Painted goby [Pomatoschistus pictus (Malm 1865)] produce two types of calls (Vicente et al., 2015). Drums (in G1) and thumps (in G2) are made to attract and court females, but only drums are used during agonistic interactions Neves, 2007, 2008;Bolgan et al., 2013). ...
Fish acoustic signals play a major role during agonistic and reproductive interactions. Among the sound-generating fish, Gobiidae, a large fish taxa with 1866 valid species, is one of the most studied groups of acoustic fishes with sound production being documented in a number of species. Paradoxically, the sound producing mechanism remains poorly studied in this group. The painted goby Pomatoschistus pictus produces two distinct sounds called drums and thumps. A combination of morphological and experimental analyses involving high-speed videos synchronized with sound recordings supports that drums are produced during lateral head movements involving at least the alternate contractions of the muscles levator pectoralis originating on the skull and inserting on the pectoral girdle. These movements are reported in many Gobiidae species suggesting the pectoral-girdle based mechanism is common in the clade and could have evolved from locomotory movements.
... Numerous studies on ectotherms have demonstrated that the rate of production and the structure of communication signals can vary as a function of ambient temperature. Examples come from a wide range of taxa, including insects (Walker 1975;de Vrijer 1984;Pires and Hoy 1992;Ciceran et al. 1994;Martin et al. 2000;Ritchie et al. 2001;Hedrick et al. 2002;Greenfield and Medlock 2007;Navia et al. 2015), anurans (Gerhardt 1978;Gayou 1984;Llusia et al. 2013), and fish (Connaughton et al. 2000;Papes and Ladich 2011;Ladich and Schleinzer 2015;Vicente et al. 2015). The phenomenon crosses sensory modalities and occurs for acoustic (e.g., Gayou 1984;Martin et al. 2000; and other references above), visual (flashing fireflies: Carlson et al. 1976;Michaelidis et al. 2006), olfactory (pheromone emission in moths: Liu and Haynes 1994;Webster and Yin 1997), and electric forms of communication (signal discharges in electric fish: Dunlap et al. 2000). ...
The rate of signal production by social ectotherms is often temperature dependent. This has been typically attributed to an underlying thermal constraint on physiology, but there are other reasons why signal rates might be correlated to temperature. We tested 3 hypotheses. The maximal performance hypothesis: temperature limits motor activity at cold and hot temperatures, which predicts a hump-shape function between signal rate and temperature. The metabolic rate hypothesis: the available energy released by metabolism increases exponentially with temperature, which predicts an exponential increase in signal rates with temperature. The recipient availability hypothesis: the number of potential receivers varies with temperature, and signalers change their signal rates accordingly, which predicts an indirect association between signal rate and temperature. We tested these hypotheses using field data on the rate of advertisement display production by territorial Jamaican and Puerto Rican Anolis lizards from a variety of thermal environments, coupled with extensive observations on one montane population of A. gundlachi. In both cases, the slopes of display rate as a function of ambient temperature were statistically indistinguishable from slopes predicted by the performance hypothesis. Support for the other 2 hypotheses was weak or equivocal. This is the first study to test alternative hypotheses of why signal rates and temperature in ectotherms are correlated and to indicate that thermal performance curves measured in the lab can reliably predict important social behavior in the field.
Acoustic communication is linked to fitness traits in many animals, but under the current scenario of global warming, sound signals can be affected by rising temperatures, particularly in ectothermic organisms such as fishes. This study examines the effect of water temperature in acoustic communication in the two-spotted goby, Pomatoschistus flavescens. To address this, we looked at the effect of different temperatures on the acoustic features of drums produced by males during territorial defence and related it with their auditory sensitivity. We also analysed the differences in acoustic features between male agonistic drums and previously reported male courtship sounds, to better understand how acoustic communication may be affected by different temperature conditions. We recorded two-spotted goby males during territorial intrusions for 10 min at 16 °C, 19 °C, and 21 °C in the laboratory. We found that agonistic drums were shorter, had fewer pulses and shorter pulse periods at higher temperature, in contrast with the peak frequency that remained unaffected. Male agonistic and mating drums (recorded in a previous study) at 16 °C only differed in pulse period, which was higher in mating drums. Hearing thresholds obtained with Auditory Evoked Potentials at 16 °C, revealed higher sensitivity below 400 Hz, matching the main energy of agonistic and mating sounds. Our findings suggest that increasing temperature could potentially affect acoustic communication in this species by reducing the duration of agonistic drums, which might hinder effective communication. Nevertheless, the impact may not be significant as there was a good match between the best hearing sensitivity and the peak frequency range of their calls, which was not influenced by temperature. As fish and other organisms are increasingly threatened by multiple anthropogenic stressors, including warming, future research should address how changes in water temperature impact acoustic communication within a more realistic multi-stressor scenario.
Human disorders of the post-squalene cholesterol biosynthesis pathway frequently result in skeletal abnormalities, yet our understanding of the mechanisms involved is limited. In a forward genetic approach, we have found that a late-onset skeletal mutant, named koliber
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, is the result of a cis-acting regulatory mutation leading to loss of methylsterol monooxygenase 1 (msmo1) expression within prehypertrophic chondrocytes. Generated msmo1
nu81
knockdown mutation resulted in lethality at larva stage. We demonstrated this is a result of both cholesterol deprivation and sterol intermediate accumulation by creating a mutation eliminating activity of Lanosterol synthase (Lss). Our results indicate that double lss
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;msmo1
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and single lss
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mutants survive significantly longer than msmo1
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homozygotes. Liver-specific restoration of either Msmo1 or Lss in corresponding mutant backgrounds suppresses larval lethality. Rescued mutants develop dramatic skeletal abnormalities, with a loss of Msmo1 activity resulting in a more severe patterning defect of a near-complete loss of hypertrophic chondrocytes marked by col10a1 expression. Our analysis suggests that hypertrophic chondrocytes depend on endogenous cholesterol synthesis, and blocking C4 demethylation exacerbates the cholesterol deficiency phenotype. Our findings offer new insight into the genetic control of bone development and provide new zebrafish models for human disorders of the cholesterol biosynthesis pathway.
Fishes have evolved the largest diversity of sonic organs among vertebrates. The main group of sound producing mechanisms is based on the swimbladder. These can be vibrated by intrinsic drumming muscles located in the wall of the swimbladder (toadfishes, searobins), or by extrinsic drumming muscles, which originate on structures such as the skull, vertebral processes or body wall musculature. Extrinsic drumming muscles insert either directly on the swimbladder (e.g. pimelodid catfish, tiger perches) or vibrate the swimbladder indirectly either via broad tendons (piranhas, drums) or via bony plates (elastic springs in doradid, mochokids and ariid catfishes). Pectoral sound-producing mechanisms include vibration of the pectoral girdle (sculpins), rubbing of the enhanced pectoral spine in a groove of the shoulder girdle (catfishes), and plucking of enhanced fin tendons (croaking gouramis). In addition, sounds can be produced by other morphological structures such as dorsal fin spines, neck vertebrae and pharyngeal teeth grating. In a few taxa, such as catfishes, two different sound-producing mechanisms (swimbladder and pectoral) are present simultaneously. In several other well-known vocalizing taxa (damsel fishes, gobies, loaches) the mechanisms remain unidentified. Sound-generating mechanisms may be similarly developed in males and females (croaking gourami) or sexually dimorphic, in which case they are always better developed in males. In toadfishes males possess a relatively higher sonic muscle mass than females, whereas in some drum species muscles are totally absent in females. In the midshipman Porichthys notatus, territorial males possess larger sonic muscles than parasitic sneaker males, which steal fertilizations. In drums sonic musculature hypertrophies seasonally, a process apparently controlled by the hormone testosterone.
Fish acoustic signals associated with mating behaviour are typically low-frequency sounds produced by males when in close proximity to females. However, some species make sounds that serve the function and follow the design of advertisement calls, well known in insects, anurans, and birds. Close-range courtship acoustic signals may be used by females in mate assessment as they contain information of male quality such as size and condition. For example, sound-dominant frequency, amplitude, and fatigue resistance may signal body size whereas pulse period (i.e. muscle contraction rate) and calling activity are related with body condition in some species. Some signal features, such as sound pulse number, may carry multiple messages including size and condition. Playback experiments on mate choice of a restricted number of species suggest that females prefer vocal to silent males and may use sound frequency, amplitude, and mainly calling rate
when assessing males. The assessment of males by females becomes more challenging when males engage in choruses or when sounds are otherwise masked by anthropogenic noise but almost nothing is known about how these aspects affect mating decisions and fish reproductive success.
Fishes have evolved multiple mechanisms for sound production, many
5 of which utilize sonic muscles that vibrate the swimbladder or the rubbing of bony
6 elements. Sonic muscles are among the fastest muscles in vertebrates and typically
7 drive the swimbladder to produce one sound cycle per contraction. These muscles
8 may be extrinsic, typically extending from the head to the swimbladder, or intrinsic,
9 likely a more-derived condition, in which muscles attach exclusively to the bladder
10 wall. Recently discovered in Ophidiiform fishes, slow muscles stretch the swim-
11 bladder and associated tendons, allowing sound production by rebound (cock and
12 release). In glaucosomatids, fast muscles produce a weak sound followed by a
13 louder one, again produced by rebound, which may reflect an intermediate in the
14 evolution of slow to superfast sonic muscles. Historically, the swimbladder has
15 been modeled as an underwater resonant bubble. We provide evidence for an
16 alternative hypothesis, namely that bladder sounds are driven as a forced rather than
17 a resonant response, thus accounting for broad tuning, rapid damping, and direc-
18 tionality of fish sounds. Cases of sounds that damp slowly, an indication of reso-
19 nance, are associated with tendons or bones that continue to vibrate and hence drive
20 multiple cycles of swimbladder sound. Stridulation sounds, best studied in catfishes
21 and damselfishes, are produced, respectively, as a series of quick jerks causing
22 rubbing of a ribbed process against a rough surface or rapid jaw closing mediated
23 by a specialized tendon. A cladogram of sonic fishes suggests that fish sound
24 production has arisen independently multiple times.
Background
In ectothermal animals such as fish, -temperature affects physiological and metabolic processes. This includes sensory organs such as the auditory system. The reported effects of temperature on hearing in eurythermal otophysines are contradictory. We therefore investigated the effect on the auditory system in species representing two different orders.
Methodology/Principal Findings
Hearing sensitivity was determined using the auditory evoked potentials (AEP) recording technique. Auditory sensitivity and latency in response to clicks were measured in the common carp Cyprinus carpio (order Cypriniformes) and the Wels catfish Silurus glanis (order Siluriformes) after acclimating fish for at least three weeks to two different water temperatures (15°C, 25°C and again 15°C). Hearing sensitivity increased with temperature in both species. Best hearing was detected between 0.3 and 1 kHz at both temperatures. The maximum increase occurred at 0.8 kHz (7.8 dB) in C. carpio and at 0.5 kHz (10.3 dB) in S. glanis. The improvement differed between species and was in particular more pronounced in the catfish at 4 kHz. The latency in response to single clicks was measured from the onset of the sound stimulus to the most constant positive peak of the AEP. The latency decreased at the higher temperature in both species by 0.37 ms on average.
Conclusions/Significance
The current study shows that higher temperature improves hearing (lower thresholds, shorter latencies) in eurythermal species from different orders of otophysines. Differences in threshold shifts between eurythermal species seem to reflect differences in absolute sensitivity at higher frequencies and they furthermore indicate differences to stenothermal (tropical) species.
We tested the hypothesis that females of a small vocal marine fish with exclusive paternal care, the painted goby, prefer high parental-quality mates such as large or high condition males. We tested the effect of male body size and male visual and acoustic courtship behaviour (playback experiments) on female mating preferences, by measuring time spent near one of a two-choice stimuli. Females did not show preference for male size but preferred males that showed higher levels of courtship, a trait know to advertise condition (fat reserves). Also, time spent near the preferred male depended on male courtship effort. Playback experiments showed that when sound was combined with visual stimuli (a male confined in a small aquarium placed near each speaker), females spent more time near the male associated with courtship sound than with the control male (associated with white noise or silence). Although male visual courtship effort also affected female preference in the pre-playback period, this effect decreased during playback and disappeared in the post-playback period. Courtship sound stimuli alone did not elicit female preference in relation to a control. Taken together, the results suggest that visual and mainly acoustic courtship displays are subject to mate preference and may advertise parental quality in this species. Our results indicate that visual and acoustic signals interplay in a complex fashion and highlight the need to examine how different sensory modalities affect mating preferences in fish and other vertebrates.
Gobiidae, the largest fish family (>1500 species), has species from at least 10 genera that produce sounds for communication. Studies focused on goby sound production mechanisms have suggested that sounds are produced by the forcible ejection of water through small apertures in the opercles (hydrodynamic mechanism). The present study was a multidisciplinary investigation (morphology, muscle histology, high-speed video, sound analysis and electromyography) of the sound emission mechanism in Gobius paganellus, which produces both pulsed and tonal calls. Two populations were used, from Brittany and Venice. In the French population, sounds were accompanied by a suite of coordinated movements of the buccal, branchial and opercular regions. This was not the case in the Venetian population, and thus the direct role of head movements in sound production was rejected. The hydrodynamic mechanism hypothesis was also rejected in G. paganellus on the basis of sound oscillogram shape and because sounds are still produced after the opercles and hyohyoid muscles are cut. The use of both electromyography and electron microscopy showed that the levator pectoralis muscle, which originates on the skull and inserts on the dorsal tip of the cleithrum, is involved in sound production. We propose that the contraction of this muscle and associated vibration of the large radials is used to make sounds. In addition, we propose that different sound types (pulsed sounds and tonal calls) could occur because of differences in fish size.
Acoustic signals can encode crucial information about species identity and individual quality. We recorded and compared male courtship drum sounds of the sand goby Pomatoschistus minutus and the painted goby P. pictus and examined if they can function in species recognition within sympatric populations. We also examined which acoustic features are related to male quality and the factors that affect female courtship in the sand goby, to determine whether vocalisations potentially play a role in mate assessment. Drums produced by the painted goby showed significantly higher dominant frequencies, higher sound pulse repetition rates and longer intervals between sounds than those of the sand goby. In the sand goby, male quality was predicted by visual and acoustic courtship signals. Regression analyses showed that sound amplitude was a good predictor of male length, whereas the duration of nest behaviour and active calling rate (i.e. excluding silent periods) were good predictors of male condition factor and fat reserves respectively. In addition, the level of female courtship was predicted by male nest behaviour. The results suggest that the frequency and temporal patterns of sounds can encode species identity, whereas sound amplitude and calling activity reflects male size and fat reserves. Visual courtship duration (nest-related behaviour) also seems relevant to mate choice, since it reflects male condition and is related to female courtship. Our work suggests that acoustic communication can contribute to mate choice in the sand goby group, and invites further study.
In 2007, the Intergovernmental Panel on Climate Change projected an average global air temperature increase of 1.1-6.4°C by the end of the 21st century. Although the tropics are predicted to experience less extreme temperature increases than regions of higher latitude, tropical ectotherms live close to their thermal limits, and are thus particularly vulnerable to increases in temperature. In this study, we examined how predicted patterns of global warming will affect survival and sexual traits in the Trinidadian guppy (Poecilia reticulata). Guppies were exposed from birth to one of four temperature treatments: 23°C, 25°C (control), 28°C, or 30°C. We measured brood survival and at sexual maturity, male ornamentation, sperm traits, and immune response. Our results show that increases in temperature result in guppies that have shorter, slower sperm but that there is an optimum temperature for ornamental hue at 28°C. Given the importance of sperm quality for reproduction, these results suggest population viability could be affected by warming. However, we found no difference in brood survival or immune response to a novel antigen across the treatments, indicating that survival may not be as vulnerable as previously thought. Overall, our data suggest that male sexual traits, and in particular sperm performance, are more sensitive than survival to a warming environment.
Summary
1. Females use multiple cues from different sensory modalities to choose males of high phenotypic
or genetic quality to mate with. Fish may use visual and acoustic communication during
mating, but few studies have associated multimodal signals with male quality and reproductive
success.
2. We examined whether visual and acoustic courtship signals reflect male quality and
influence mating success in the painted goby (Pomatoschistus pictus), a highly visual and vocal
fish species with paternal care. Painted gobies make conspicuous courtship visual displays such
as body quivering and eight-shaped swimming patterns and two types of sounds: drums that
are composed of a sequence of low-frequency pulses and a thump-like non-pulsed sound. We
predicted that both sensory modalities would advertise male size and condition and influence
mating success.
3. We found that larger number of pulses in a drum, lower fatigue (where fatigue is the
increase in pulse period during drum production) and higher drum absolute amplitude levels
were good predictors of larger male size. Males with high condition factor (Fulton’s K) showed
high drumming activity and low thumping and visual courtship levels. Drumming activity was
a good predictor of male fat reserves.
4. Males that succeeded to mate emitted sounds with higher number of pulses and longer pulse
periods and showed higher drumming but lower thumping activity than unsuccessful males.
All traits (except pulse period) reflected higher male Fulton’s K or fat reserves, suggesting that
females are selecting for male condition. Neither male size nor visual courtship was apparently
used in mate selection.
5. Contrary to our expectations, females did not seem to prefer larger or vigorous visually
displaying males but chose mates in better condition using multiple cues of drumming sounds.
We suggest that preference for high mate condition is related to preference for increased parental
ability and hatching success in species with paternal care. To the best of our knowledge,
this is the first study that addresses the relative role of signals from different sensory modalities
including acoustics, in advertising male quality and in contributing to reproductive success in
fish.
Gobies emit sounds during different stages of reproduction, including courtship, pre-spawning events (in the nest) and spawning. The breeding sounds of the painted goby Pomatoschistus
pictus and associated courtship behaviour were recorded in captivity and described for the first time. Males emitted thump-like sounds mainly when displaying alone in the nest and produced drumming sounds outside the nest. Thumps have never been reported for other species of the genus Pomatoschistus. Thumps were short (~80 ms) very-low frequency (below 100 Hz) non-pulsed sounds, whereas drums were longer (hundreds of ms) and consisted of low frequency (~300 Hz) pulse trains. Thump characteristics varied significantly among males but also showed high within-male variability. The frequency of thump emissions and courtship behaviour (total number of courtship displays, lead and nest display) were positively correlated with male size but not with male somatic condition. Thump bursts emitted during nest displays were significantly longer than when emitted with other behaviours. These results suggest that larger males courted females more intensively, both with visual and acoustic displays, than smaller ones.
In this paper a detailed analysis of the physical structure of sounds produced by male Padogobius martensi is reported. Sound production occurs during courtship and inter-male agonistic encounters. Both aggressive and courtship calls are made up of rapidly repeated pulses, with a pulse repetition rate decreasing through the course of the emission. By means of computerized analysis, the pulse repetition rate, its modulation and sound duration were determined. The water temperature was found to exert a marked and significant effect on the above parameters. In particular, the temperature directly affects the pulse rate and its decrease through the course of the emission (i.e. frequency modulation) and inversely affects sound duration. By contrast, size of the calling animal does not significantly influence the sound parameters considered. Aggressive sounds last longer and -have a lower pulse repetition rate than the courtship sounds. Moreover, aggressive sounds appear more variable than the courtship ones as far as pulse rate and duration are concerned.
The male Arno goby Padogobius nigricans courts ripe females by emitting sounds at a high rate, mainly from the nest hollow. Laboratory observations revealed that each sound is an almost pure tone wave showing marked amplitude modulation and decrease of frequency throughout its length. The mean tone frequency averaged 79.4 Hz and the sound duration averaged 327 ms. Both these sound parameters were significantly affected by the temperature of the water. Acoustic behaviour during sexual interactions was compared for tank-confined males and males from a community group. The fact that acoustic activity of the male peaked when the female stayed motionless at the nest entrance suggested that the sound emitted by the male P. nigricans has a role as an advertising signal. Observation of spawning behaviour showed the emission of sounds by the male rapidly diminished and eventually ceased shortly after the beginning of oviposition. Thus, the male sound seems not to be a functional component of the spawning behaviour. Finally, data on vocal behaviour of this species were examined within a comparative framework, also taking into consideration phylogenetic relationships between Italian freshwater gobies.
Male courtship acoustic signals from five Lake Malawi cichlid fish species of the Pseudotropheus zebra complex were recorded and compared. Sounds made by males of P. zebra, Pseudotropheus callainos and the undescribed species known as Pseudotropheus ‘zebra gold’ from Nkhata Bay, and Pseudotropheus emmiltos and Pseudotropheus faizilberi from Mphanga Rocks, differed significantly in the number of pulses and in pulse period. The largest differences in acoustic variables were found among the sympatric Mphanga Rocks species that, in contrast to the other three species, show relatively minor differences in male colour and pattern. These findings suggest that interspecific mate recognition is mediated by multimodal signals and that the mass of different sensory channels varies among sympatric species groups. This study also showed that sound peak frequency was significantly negatively correlated with male size and that sound production rate increased significantly with courtship rate.
Acoustic communication is critical for reproductive success in the oyster toadfish Opsanus tau. While previous studies have examined the acoustic characteristics, behavioral context, geographical variation, and seasonality
of advertisement boatwhistle sound production, there is limited information on the grunt or other non-advertisement vocalizations
in this species. This study continuously monitored sound production in toadfish maintained in an outdoor habitat for four
months to identify and characterize grunt vocalizations, compare them with boatwhistles, and test for relationships between
the incidence of grunt vocalizations, sound characteristics and environmental parameters. Oyster toadfish produced grunts
in response to handling, and spontaneous single (70% of all grunts), doublet (10%), and trains of grunts (20%) throughout
the May to September study period. Grunt types varied in pulse structure, duration, and frequency components, and were shorter
and of lower fundamental frequency than the pulse repetition rate of boatwhistles. Higher water temperatures were correlated
with a greater number of grunt emissions, higher fundamental frequencies, and shorter sound durations. The number of grunts
per day was also positively correlated with daylength and maximum tidal amplitude differences (previously entrained) associated
with full and new moons, thus providing the first demonstration of semilunar vocalization rhythms in the oyster toadfish.
These data provide new information on the acoustic repertoire and the environmental factors correlated with sound production
in the toadfish, and have important implications for seasonal acoustic communication in this model vocal fish.
The boatwhistle, the mating call of the oyster toadfish Opsanus tau L. undergoes a pronounced seasonal cycle. The fundamental frequency increases to a peak early in the summer and then decreases markedly in the middle of July. The call duration decreases coincident with the fundamental frequency. It is hypothesized that these fluctuations are controlled by hormonal factors although temperature exerts a direct effect on the fundamental frequency.
The fundamental frequency of the boatwhistle in early season is higher in southern populations than in northern ones. Part of this increase is attributed to increased temperature of southern waters. Call duration, which is independent of temperature, varies irregularly up and down the coast.
The codfish family, Gadidae, contains many vocal species. The sounds produced are species-characteristic and relatively simple. Unusually within this family, the haddock Melanogrammus aeglefinus, produces a range of sounds in different contexts. Both male and female haddock produce short sequences of repeated knocks during agonistic encounters. During the spawning season, however, male fish produce sounds which vary in their characteristics as courtship proceeds. The repertoire of the male fish consists of a graded series of sounds ranging from a short series of slowly repeated knocks to long sounds of rapidly repeated knocks. The fastest sounds are heard as a continuous humming. Different behavioural acts leading up to the mating embrace are associated with particular sounds, the sounds becoming longer and faster as the level of arousal of the male increases. It is suggested that the sounds serve to bring male and female fish together in the same part of the ocean, and that the sounds also play a role in synchronising the reproductive behaviour of the male and female.
Acoustic communication in Gryllus firmus is temperature-coupled: temperature induces parallel changes in male calling song temporal pattern, and in female preference for song. Temperature effects on song production and recognition networks were localized by selectively warming head or thorax or both head and thorax of intact crickets, then eliciting aggression song production (males) or phonotaxis to synthetic calling song (females). Because male song is produced by a thoracic central pattern generator (CPG), and because head ganglia are necessary for female song recognition, measurements of female phonotaxis under such conditions may be used to test the following competing hypotheses about organization of the song recognition network: 1. A set of neurons homologous to the male song CPG exist in the female, and are used as a template that determines preferred values of song temporal parameters for song pattern recognition (the common neural elements hypothesis), and 2. temporal pattern preference is determined entirely within the head ganglia.
Neither selective warming of the head nor of the thorax was effective in changing female song preference, but simultaneous warming of head and thorax shifted preference toward a faster song in most preparations, as did warming the whole animal by raising ambient temperature. These results suggest that phonotactic preference for song temporal pattern is plurisegmentally determined in field crickets.
Selective wanning experiments during aggression song production in males revealed that syllable period is influenced but not completely determined by thoracic temperature; head temperature is irrelevant. The song CPG appears to receive some rate-setting information from outside the thoracic central nervous system.
Sound production and hearing sensitivity of ectothermic animals are affected by the ambient temperature. This is the first study investigating the influence of temperature on both sound production and on hearing abilities in a fish species, namely the neotropical Striped Raphael catfish Platydoras armatulus.
Doradid catfishes produce stridulation sounds by rubbing the pectoral spines in the shoulder girdle and drumming sounds by an elastic spring mechanism which vibrates the swimbladder. Eight fish were acclimated for at least three weeks to 22°, then to 30° and again to 22°C. Sounds were recorded in distress situations when fish were hand-held. The stridulation sounds became shorter at the higher temperature, whereas pulse number, maximum pulse period and sound pressure level did not change with temperature. The dominant frequency increased when the temperature was raised to 30°C and the minimum pulse period became longer when the temperature decreased again. The fundamental frequency of drumming sounds increased at the higher temperature. Using the auditory evoked potential (AEP) recording technique, the hearing thresholds were tested at six different frequencies from 0.1 to 4 kHz. The temporal resolution was determined by analyzing the minimum resolvable click period (0.3-5 ms). The hearing sensitivity was higher at the higher temperature and differences were more pronounced at higher frequencies. In general, latencies of AEPs in response to single clicks became shorter at the higher temperature, whereas temporal resolution in response to double-clicks did not change.
These data indicate that sound characteristics as well as hearing abilities are affected by temperatures in fishes. Constraints imposed on hearing sensitivity at different temperatures cannot be compensated even by longer acclimation periods. These changes in sound production and detection suggest that acoustic orientation and communication are affected by temperature changes in the neotropical catfish P. armatulus.
The macroevolutionary events leading to neural innovations for social communication, such as vocalization, are essentially
unexplored. Many fish vocalize during female courtship and territorial defense, as do amphibians, birds, and mammals. Here,
we map the neural circuitry for vocalization in larval fish and show that the vocal network develops in a segment-like region
across the most caudal hindbrain and rostral spinal cord. Taxonomic analysis demonstrates a highly conserved pattern between
fish and all major lineages of vocal tetrapods. We propose that the vocal basis for acoustic communication among vertebrates
evolved from an ancestrally shared developmental compartment already present in the early fishes.
Temporal patterning is an essential feature of neural networks producing precisely timed behaviours such as vocalizations that are widely used in vertebrate social communication. Here we show that intrinsic and network properties of separate hindbrain neuronal populations encode the natural call attributes of frequency and duration in vocal fish. Intracellular structure/function analyses indicate that call duration is encoded by a sustained membrane depolarization in vocal prepacemaker neurons that innervate downstream pacemaker neurons. Pacemaker neurons, in turn, encode call frequency by rhythmic, ultrafast oscillations in their membrane potential. Pharmacological manipulations show prepacemaker activity to be independent of pacemaker function, thus accounting for natural variation in duration which is the predominant feature distinguishing call types. Prepacemaker neurons also innervate key hindbrain auditory nuclei thereby effectively serving as a call-duration corollary discharge. We propose that premotor compartmentalization of neurons coding distinct acoustic attributes is a fundamental trait of hindbrain vocal pattern generators among vertebrates.
The evolutionary dynamic of courtship signaling systems is driven by the interaction between male trait distributions and female preferences. This interaction is complex because females may choose mates based on multiple components of male signals, and female preference functions may vary depending on mate availability, female reproductive state, and environmental conditions. In Photinus fireflies (Coleoptera: Lampyridae), flying males emit bioluminescent flash signals to locate sedentary females, which reply selectively to attractive male flash signals with their own response flash. In this study, we first examined temporal variation in the paired-pulse flash patterns produced by Photinus greeni males in the field and found significant among-male variation (∼70% of total variation) in interpulse intervals (IPIs). There was no significant relationship between male IPI and spermatophore size, suggesting that P. greeni male courtship signals do not provide females with reliable indicators of male material resources. In laboratory playback experiments, we presented P. greeni females with simulated flash signals to assess how IPI and pulse duration independently affected the likelihood of female flash response. We also examined the effects of female body mass and time during the mating season on female preference functions, hypothesizing that females would be less discriminating when they were heavier (more fecund) and when mate availability declined. We found that P. greeni females discriminated among signals within their species' range based primarily on flash pattern IPI. Neither the time during the mating season nor female weight altered female preference functions for IPI, although season did influence female response to pulse duration. These results reveal that P. greeni females discriminate among conspecific males based primarily on male IPIs, the same signal character previously shown to be important for firefly species recognition. Field playback experiments indicated that female responsiveness peaked near the average IPI given by males at different ambient temperatures, suggesting that fireflies exhibit temperature coupling similar to that seen in many acoustically signaling animals. Copyright 2006.
Most animal species are cold-blooded, and their neuronal circuits must maintain function despite environmental temperature fluctuations. The central pattern generating circuits that produce rhythmic motor patterns depend on the orderly activation of circuit neurons. We describe the effects of temperature on the pyloric rhythm of the stomatogastric ganglion of the crab, Cancer borealis. The pyloric rhythm is a triphasic motor pattern in which the Pyloric Dilator (PD), Lateral Pyloric (LP), and Pyloric (PY) neurons fire in a repeating sequence. While the frequency of the pyloric rhythm increased about 4-fold (Q(10) approximately 2.3) as the temperature was shifted from 7 degrees C to 23 degrees C, the phase relationships of the PD, LP, and PY neurons showed almost perfect temperature compensation. The Q(10)'s of the input conductance, synaptic currents, transient outward current (I(A)), and the hyperpolarization-activated inward current (I(h)), all of which help determine the phase of LP neuron activity, ranged from 1.8 to 4. We studied the effects of temperature in >1,000 computational models (with different sets of maximal conductances) of a bursting neuron and the LP neuron. Many bursting models failed to monotonically increase in frequency as temperature increased. Temperature compensation of LP neuron phase was facilitated when model neurons' currents had Q(10)'s close to 2. Together, these data indicate that although diverse sets of maximal conductances may be found in identified neurons across animals, there may be strong evolutionary pressure to restrict the Q(10)'s of the processes that contribute to temperature compensation of neuronal circuits.
Lusitanian toadfish males that provide parental care rely on acoustic signals (the boatwhistle) to attract females to their nest. We test the hypothesis that male quality, namely male size and condition that are relevant for parental success, is reflected in vocal activity and boatwhistle characteristics and thus advertised to females. We recorded 22 males over a week during the peak of the breeding season. Calling rate and calling effort (percentage of time spent calling) strongly reflected male condition (lipid content of somatic muscles) and to a smaller extent sonic muscle hypertrophy and larger gonads. Males in better condition (increased body lipid and relative higher liver mass) also contracted the sonic muscles at faster rate as shown by the shorter boatwhistle pulse periods. Amplitude modulation reflected the degree of sonic muscle hypertrophy. None of the measured male quality parameters were good predictors of boatwhistle duration and dominant frequency. Altogether this study strongly suggests that Lusitanian toadfish males advertise their quality to females primarily with boatwhistle calling rate and calling effort, which mainly reflect male condition. Because pulse period had low variability, consistent with the existence of a vocal central pattern generator, we suggest that males that sustain sonic muscles contraction at a very fast rate close to their physiological limit may be honestly advertising their quality (condition). Similarly, males that produce boatwhistles with higher amplitude modulation, a feature that seems dependent on sonic muscle hypertrophy, could be more attractive to females.
Across all major vertebrate groups, androgen receptors (ARs) have been identified in neural circuits that shape reproductive-related behaviors, including vocalization. The vocal control network of teleost fishes presents an archetypal example of how a vertebrate nervous system produces social, context-dependent sounds. We cloned a partial cDNA of AR that was used to generate specific probes to localize AR expression throughout the central nervous system of the vocal plainfin midshipman fish (Porichthys notatus). In the forebrain, AR mRNA is abundant in proposed homologs of the mammalian striatum and amygdala, and in anterior and posterior parvocellular and magnocellular nuclei of the preoptic area, nucleus preglomerulosus, and posterior, ventral and anterior tuberal nuclei of the hypothalamus. Many of these nuclei are part of the known vocal and auditory circuitry in midshipman. The midbrain periaqueductal gray, an essential link between forebrain and hindbrain vocal circuitry, and the lateral line recipient nucleus medialis in the rostral hindbrain also express abundant AR mRNA. In the caudal hindbrain-spinal vocal circuit, high AR mRNA is found in the vocal prepacemaker nucleus and along the dorsal periphery of the vocal motor nucleus congruent with the known pattern of expression of aromatase-containing glial cells. Additionally, abundant AR mRNA expression is shown for the first time in the inner ear of a vertebrate. The distribution of AR mRNA strongly supports the role of androgens as modulators of behaviorally defined vocal, auditory, and neuroendocrine circuits in teleost fish and vertebrates in general.
Although acoustic communication is an integral part of cichlid behaviour, its mechanism has never been identified before. In the present study, a combination of approaches was used to investigate the sound-producing mechanism of Oreochromis niloticus. Synchronisation of high-speed video data (500 frames s(-1)) and cineradiographies (250 frames s(-1)) with the sound recordings made it possible to locate the different body parts involved in sound production in territorial males. Sounds are made during a backward movement of the pelvic and pectoral girdles and a forward movement of the second pterygiophore of the anal fin. Various electrostimulation experiments, dissections and observation of histological cross-sections revealed a set of bundles (that we call the vesica longitudinalis) situated in the hypaxial musculature, ventro-laterally to the swimbladder. Contraction of these bundles should result in compression of the rib cage and also of the swimbladder, because of its close association with the serosa and ribs. Deflation of the swimbladder resulted in a reduced sound intensity.
Walk near woods or water on any spring or summer night and you will hear a bewildering (and sometimes deafening) chorus of frog, toad, and insect calls. How are these calls produced? What messages are encoded within the sounds, and how do their intended recipients receive and decode these signals? How does acoustic communication affect and reflect behavioral and evolutionary factors such as sexual selection and predator avoidance? H. Carl Gerhardt and Franz Huber address these questions among many others, drawing on research from bioacoustics, behavior, neurobiology, and evolutionary biology to present the first integrated approach to the study of acoustic communication in insects and anurans. They highlight both the common solutions that these very different groups have evolved to shared challenges, such as small size, ectothermy (cold-bloodedness), and noisy environments, as well as the divergences that reflect the many differences in evolutionary history between the groups. Throughout the book Gerhardt and Huber also provide helpful suggestions for future research.
Being ectothermic, fish body temperature generally depends on ambient water temperature. Thus, ambient temperature might affect various sensory systems, including hearing, as a result of metabolic and physiological processes. However, the maintenance of sensory functions in a changing environment may be crucial for an animal's survival. Many fish species rely on hearing for acoustic orientation and communication. In order to investigate the influence of temperature on the auditory system, channel catfish Ictalurus punctatus was chosen as a model for a eurytherm species and the tropical catfish Pimelodus pictus as a model for a stenotherm fish. Hearing sensitivity was measured with animals acclimated or unacclimated to different water temperatures. Ambient water temperature significantly influenced hearing thresholds and the shape of auditory evoked potentials, especially at higher frequencies in I. punctatus. Hearing sensitivity of I. punctatus was lowest at 10 degrees C and increased by up to 36 dB between 10 degrees C and 26 degrees C. Significant differences were also revealed between acclimated and unacclimated animals after an increase in water temperature but not a decrease. By contrast, differences in hearing thresholds were smaller in P. pictus, even if a similar temperature difference (8 degrees C) was considered. However, P. pictus showed a similar trend as I. punctatus in exhibiting higher hearing sensitivity at the highest tested temperature, especially at the highest frequency tested. The results therefore suggest that the functional temperature dependence of sensory systems may differ depending upon whether a species is physiologically adapted to tolerate a wide or narrow temperature range.
Vocalizations of Xenopus laevis are generated by central pattern generators (CPGs). The advertisement call of male X. laevis is a complex biphasic motor rhythm consisting of fast and slow trills (a train of clicks). We found that the trill rate of these advertisement calls is sensitive to temperature and that this rate modification of the vocal rhythms originates in the central pattern generators. In vivo the rates of fast and slow trills increased linearly with an increase in temperature. In vitro a similar linear relation between temperature and compound action potential frequency in the laryngeal nerve was found when fictive advertisement calls were evoked in the isolated brain. Temperature did not limit the contractile properties of laryngeal muscles within the frequency range of vocalizations. We next took advantage of the temperature sensitivity of the vocal CPG in vitro to localize the source of the vocal rhythms. We focused on the dorsal tegmental area of the medulla (DTAM), a brain stem nucleus that is essential for vocal production. We found that bilateral cooling of DTAM reduced both fast and slow trill rates. Thus we conclude that DTAM is a source of biphasic vocal rhythms.
Evolutionary neurobiologists want to know how neuronal properties (or traits) have been modified to subserve adaptive changes in behavioral phenotypes. Homology can provide a conceptual framework to distinguish the separate contributions of phylogenetic factors and current adaptive modifications to extant traits and behaviors. In this essay, a suite of nine vocal/sonic motor traits are compared in two orders of teleost fishes, the Batrachoidiformes and Scorpaeniformes. Only three of the traits are modified among Scorpaeniformes, the more advanced group. The large number of conserved characters among the study species suggests their sonic motor systems are homologs. This conclusion is consistent with the known phylogeny of teleosts and further implies that homologous sonic motor traits are more extensively modified among more recently evolved members (in this case the Scorpaeniformes) of the teleostean lineage. Since homology implies a common ontogenetic history for any trait, modifications thereof can potentially be linked to changes in identifiable developmental events, which themselves are homologs. Several hypotheses are proposed to account for the origins of modified sonic traits. The further demonstration that modified traits of the sonic motor system are in fact adaptations sets the stage for behavioral ecological studies that attempt to understand why the modified traits underlie behavioral changes that increase an individual's fitness.
In the past 20 years a total of 14 gobiid species were caught, by LNETI/INETT researchers, in five coastal ecosystems on soft bottoms of the Portuguese coast. Species distribution and ecological significance of species abundance are discussed.
While studies of sonic mechanisms among vertebrates date back more than 100 years, the past 25 years have witnessed a burgeoning of interest in the bioacoustics and behavioral ecology of sound production among fishes, including in its neural basis. Here, we review the body of comparative literature on the neuroanatomical, neurophysiological, and neuroendocrine mechanisms of sound production/vocalization among fishes. Most studies have focused on teleosts, the most species-rich group of living vertebrates. The past decade alone has witnessed the demonstration of (1) an extensively connected vocal-acoustic network at forebrain
, midbrain
, and hindbrain
levels, (2) distinct neural populations comprising a central pattern generator (CPG) that directly determines the physical attributes of social context-dependent sounds including pulse repetition rate (PRR)
, fundamental frequency
, duration
, and amplitude
, (3) a highly conserved pattern for the evolutionary developmental origin of vocal CPGs between fishes and tetrapods
, (4) shared origins between vocal CPGs that are dedicated to sound production and pectoral appendage motor systems that function in both acoustic signaling and locomotion, and (5) forebrain, midbrain, and hindbrain targets in the vocal-acoustic network for the modulatory actions of steroid hormones
and neuropeptides
. In sum, the relative simplicity of acoustic signaling in fishes and of the underlying neural circuitry offer both insights into the evolutionary history of sound producing mechanisms among all vertebrates, and practical advantages for investigating adaptations at the cellular and network levels of neural organization that sculpt behavioral phenotypes.
Sound communication comprising the production and detection of acoustic signals is affected by ambient temperature in ectothermic animals. In the present study we investigated the effects of temperature on sound production and characteristics in the croaking gourami Trichopsis vittata, a freshwater fish from Southeast Asia possessing a highly specialized sound-generating mechanism found only in a single genus. The croaking gourami produces pulsed sounds by stretching and plucking two enhanced pectoral fin tendons during rapid pectoral fin beating. Croaking sounds typically consist of a series of double-pulsed bursts with main energies between 1 and 1.5kHz. Sounds were recorded during dyadic contests between two males at three different temperatures (25°, 30° and 35°C). The mean dominant frequency increased with rising temperature from 1.18 to 1.33kHz, whereas temporal characteristics decreased. The sound interval dropped from 492 to 259ms, the burst pulse period from 51 to 35ms and the pulse period from 5.8 to 5.1ms. In contrast, the number of sounds and number of bursts within a sound were not affected by temperature. The current study shows that spectral and temporal characteristics of sounds are affected in different ways by temperature in the croaking gourami, whereas the numbers of sounds and bursts remain unaffected. We conclude that acoustic communication in gouramis is affected by changes in ambient temperature.
Copyright © 2014. Published by Elsevier Inc.
The plainfin midshipman Porichthys notatus has two male reproductive morphs, ‘Type I’ and ‘Type II’, which are distinguishable by their physical traits alone. Type I males are eight times larger in body mass than Type II males and have a six-fold larger relative sonic (vocal) muscle mass than Type II males. In contrast, the testicles of Type II males are seven times larger than those of Type I males. This study demonstrates morph-specific patterns of reproduction, including acoustic signals, for Type I and II males. Field censuses of nests showed that only Type 1 males maintained nests. Type II males and females transiently appeared in these nests in association with each other. Infra-red video and hydrophone recordings in aquaria showed that Type I males maintained nests and readily vocalized. Long-duration ‘hums’ and sequences of short-duration ‘grunts’ were produced during advertisement and agonistic contexts, respectively. Humming Type I males attracted females to their nests, pair-spawned, and then guarded egg clutches alone. By contrast, Type II males neither acoustically courted females nor maintained available nest sites, but rather ‘sneak-’ or ‘satellite-spawned’ at the nests of Type I males. Type II males infrequently produced low amplitude, short duration grunts that were similar in spectral, temporal and amplitude characteristics to the grunts of females. Type II males appear to be obligate sexual parasites of the nest-building, mate-calling, and egg-guarding Type I males. The dimorphic body and vocal muscle traits of the two male morphs in the plainfin midshipman are thus paralleled by a divergence in their reproductive tactics and the properties of their acoustic signals.
The boatwhistle sound produced by male toadfish during the reproductive season attracts females to the nest site. Boatwhistles consist of a series of rapidly produced, amplitude modulated ‘pulses’ of sound that are generated by specific muscles of the gas bladder. Previous studies have shown that boatwhistle characteristics vary with temperature and geographic location. This study investigated the normal range of variation in boatwhistles produced by males in a northern population of O. tau. Multiple boatwhistles were recorded from individuals at different sites around Waquoit Bay, Massachusetts. Multiple boatwhistles were recorded at different sites to assess the range of variation in boatwhistle production from this population. Pulse repetition rates varied from a low of 125 pulses/sec at 16 °C to a high of 219 pulses/sec at 21 °C. Careful examination of recordings from different sites indicated that individuals vary in the durations of their boatwhistles as well as in the pulse repetition rates during the very consistently produced second segment of the call. In particular, pulse repetition rate (PRR) varied significantly (p < 0.001) among most individuals recorded at the same temperatures. Psychophysical testing as well as behavioral choice experiments are needed to assess the relative importance of PRR and spectral cues in species recognition and/or mate choice.
Specimens and nests of Pomatoschistus
pictus adriaticus have been caught for the first time along the French Mediterranean shore (Gulf of Lions). Six types of nests are found on sandy-gravelly bottom at 10 m depth and 25·3 to 27·5 g l[minus sign]1 salinity, using in 84·7% of cases, a valve of Cardium
edule (3·3[less-than-or-eq, slant]weight g[less-than-or-eq, slant]40·6; 507[less-than-or-eq, slant]surface mm2[less-than-or-eq, slant]2490). Nest size, egg patch, surface area and nesting fecundity are positively correlated. Nesting fecundity varies between 669 and 4690 eggs. For a similar egg diameter, the egg height is less than that of P.
minutus which spawns on the same bottom and localities. Larval length at hatching varies from 1·70 to 2·67 mm.
Sound production of 11 Mediterranean goby species, belonging to five different genera, have been comparatively analysed on the basis of the quantitative properties of the acoustic signal emitted by the male in both the reproductive and aggressive context. The results obtained showed that three groups of species can be recognized on the basis of signal similarity: the larger sized species (genus Padogobius and Gobius paganellus) producing tonal sounds, showing high values of pulse rate and low values of duration; the larger-sized species producing grunt sounds (genus Gobius and Zosterisessor) with low pulse rate and low duration; and the small-sized species producing grunt sounds (genus Pomatoschistus and Knipowitschia) with low pulse rate and high duration. The comparison between these results and those found in previous studies suggests congruence between the acoustic affinities among species and that obtained by means of morphological and genetic data. Furthermore, first hypotheses on the evolution of acoustic communication and the associated mechanisms in this fish group are suggested. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 93, 763–778.
Life-history reactions of a pumpkinseed Lepomis gibbosus population in north-eastern France exposed to heated waters were studied. The study was conducted from 2001 to 2003 in an artificial reservoir, adjacent to a nuclear power plant, in which water temperatures are cool in winter (8·2–12·4° C) and rise early in spring (April: 14·7° C) nearly 5° C and 3° C over the temperature of its tributary, respectively. Fast growth among young-of-the-year, precocious maturity and short life span were observed, in contrast to related studies. The short life span appeared to be the price paid for early maturity in breeding fish, which suffered high mortality rates just after their first reproduction.
Seasonal variation of sound production, which includes boatwhistles, grunts, croaks and double croaks, was studied in the Lusitanian toadfish Halobatrachus didactylus. Boatwhistles were emitted during the mating season in contrast with the other sound types, which were emitted all year round.
In the two acridid speciesChorthippus parallelus andCh. montanus, the sound template by which females recognize male song varies with temperature, as does the song itself. At relatively high temperatures the females respond best to simulated songs with high syllable frequencies, and at lower temperatures songs with lower syllable frequencies are preferred.
The temperature around the supraesophageal and metathoracic ganglia of female grasshoppers was monitored by implanted thermocouples, and either the head or the thorax was warmed selectively while the animal was free to move (within the imits of the wires). Then simulations of the conspecific song varying in syllable frequency corresponding to different song temperatures were presented, and the stridulatory responses of the animals were observed.
The results were as follows. 1. Song recognition (in particular, the position of the peak of the response curve) depended on the temperature of the head. 2. The rate of stridulatory hindleg movement was determined by the temperature of the thoracic ganglia.
This result provides strong evidence against the genetic coupling hypothesis.
We studied the effect of ambient temperature (13C–34C) on the vibratory courtship communication of the wandering spider Cupiennius salei.1.
Male vibratory signals. The durations of most signal parameters decreased linearly with increasing temperature. The number of syllables in one series, and that of pulses in one syllable did not change with temperature, however. The ratios of the durations of a series and interseries, and of a syllable and a sequence (duty cycle) remained largely unchanged by temperature as well.
2.
Female vibratory response. The duration of the female response to the male vibration decreased with increasing temperature whereas the female response rate remained roughly constant between 13C and 25C. Females exposed to different temperatures favored male signals recorded in the same temperature range. To compensate for temperature dependent changes of male vibrations the female may therefore rely on the adjustment of her receiving system and/or temperature invariant signal parameters. Among these the duty cycle is considered particularly important.
3.
Temporal relationship. The onset of the female response often occurred at the supposed onset of a male syllable, had the male continued to signal after completing the series. This synchronization may be advantageous in a noisy environment.
1.
Tigerfische (Therapon jarbua) leben in der Jugend gesellig und bilden mit anderen Artgenossen Schwrme. Zeitweilig suchen einzelne Individuen Schlupfwinkel auf, die sie gegen Artgenossen verteidigen. Ihre erhhte Aggression zeigt sich durch eine Aggressivfrbung an, bei der die Lngsstreifen im Farbmuster blasser und die Augen dunkler sind. Auch im Schwarm lebende Fische tragen zeitweilig die Aggressivfrbung und sind gegen die brigen Artgenossen angriffslustiger.
2.
Beim Umherschwimmen der Jungfische ist eine lebhafte akustische Aktivitt zu beobachten: Zahlreich sind kurzdauernde und in unregelmiger Folge auftretende Trommellaute. Dazwischen treten Signale von lngerer Dauer und meist auch von grerer Intensitt auf, die Fische whrend eines Angriffes auslsen. Sie dienen der Drohung und werden deshalb Drohlaute genannt.
3.
Fische mittlerer Gre leben solitr und attackieren andere Artgenossen fortwhrend, sofern der Lebensraum nicht zu klein ist. Dabei spielen Lautuerungen eine wichtige Rolle. Je nach der Heftigkeit eines Angriffes verwendet ein Fisch rasche Folgen von Trommellauten, Trommellautfolgen mit eingeschalteten Drohlauten oder einzelne Drohlaute. Die Signale sind vielfach begleitet von optisch wahrnehmbaren Drohgebrden wie Maulsperren und Kiemendeckelspreizen. Attackierte Fische schwimmen weg, erzeugen dabei meist Trommellaute und richten auch die vordere Rckenflosse auf.
4.
Die Trommellaute dienen der Verstndigung zwischen Artgenossen. Die Lauterzeugung der Fische geht bei solitrer Lebensweise auf ein Minimum zurck und steigt innerhalb von 30 min stark an, sofern mehrere Fische zusammenkommen. Auch geblendete Fische lsen noch Laute aus und beantworten Trommellaute anderer Individuen.
5.
Die Trommellaute der jngsten Fische bestehen aus zwei Komponenten. Mit der Grenzunahme der Tiere gehen sie mehr und mehr ineinander ber, da die Dmpfung des Resonators abnimmt. Die Laute dauern im Mittel 10 ms. Zusammen mit der Gre der Fische ndert sich auch das Spektrum der Trommellaute und die Intensitt. Bei 34 mm groen Tieren liegt das Intensittsmaximum im kontinuierlichen Spektrum bei 800 Hz, bei 10 mm langen Fischen bei 650 Hz. Der Schalldruck der Laute steigt mit der Gre an.
6.
Die Drohlaute stellen sehr rasche Folgen von Einzelschallsten dar. Die Wiederholungshufigkeit kann bei 200 Impulsen/s liegen. Die Dauer der Drohlaute hngt von der Anzahl der Impulse ab; sie sind um so lnger, je intensiver ein Fisch droht. Die Amplituden der Impulse innerhalb eines Drohlautes nehmen sehr rasch ab. Das kontinuierliche Spektrum ist breit und weist kein auffallendes Intensittsmaximum auf. Beim Rckspielen solcher Laute erhht sich bei anderen Fischen die Aggression. Diese lsen dann selbst Drohlaute aus und greifen Fische an.
7.
Die Lautproduktion der Fische wird durch die Wassertemperatur beeinflut. Sie ist bei 33 und 30 C hoch, sinkt bereits bei 25 ab und noch mehr bei 20 C. Gleichzeitig ndert sich auch der Aufbau der Drohlaute. Die Wiederholungshufigkeit der Impulse steigt bei der Erhhung der Temperatur von 20 auf 30 C um das Doppelte.
8.
nderungen der Helligkeit ben gleichfalls groen Einflu auf die Lautproduktion aus. Die Fische sind bei Dunkelheit fast stumm und beginnen bei pltzlichen Helligkeitssteigerungen augenblicklich mit der Lautproduktion. Sie dauert whrend der Hellphase an und sinkt mit einsetzender Dunkelheit sofort wieder ab. Auch auf sehr geringe Leuchtdichten reagieren die Fische, allerdings reichen sie nicht aus, um die Lautproduktion ber mehrstndige Hellperioden anzuregen. Mit Hilfe der Lautproduktion lieen sich Angaben ber die Unterschiedsschwelle der Lichtsinnesorgane bei verschiedenen Leuchtdichten bestimmen. Sie ist wahrscheinlich hher als beim Menschen.
9.
Die Laute entstehen durch die Ttigkeit zweier Muskeln, die am Schultergrtel entspringen und auf der Schwimmblase ansetzen. Auch mit nur einem Muskel knnen die Fische Laute auslsen. Diese Trommelmuskeln werden im ersten Lebensjahr angelegt, wenn die Fische 27 bis 40 mm gro sind. Beide Geschlechter sind zur Lauterzeugung fhig.
10.
Jeder Muskel besteht aus drei Sektionen, die aus zahlreichen Muskelfasern aufgebaut sind. Diese haben einen Durchmesser von 2–27 , die Mehrzahl von 17–20 . Sie sind plasmareich, enthalten im Innern die zu Bndern oder Kreisen angeordneten Fibrillen und sind nicht rot gefrbt. Die Muskeln werden vom ersten Spinalnerven innerviert. Ihre Refraktrzeit ist kleiner als 2 ms. Bis zu einer Reizfrequenz von 150 Reizen/s reagieren sie mit Einzelzuckungen, von 290 Reizen/s an mit glattem Tetanus, dazwischen mit abgestuftem, unvollstndigem Tetanus. Die Trommelmuskeln ermden rasch.
11.
Die den Tigerfischen nahe verwandte Art Therapon theraps kann ebenfalls Laute erzeugen. Sie besitzen den gleichen Aufbau wie die Trommellaute von Th. jarbua. Die Fische lsen sie bei Angriffen auf Artgenossen aus. Den Drohlauten entsprechende Signale konnte ich nicht feststellen. Der Lautapparat ist wie bei Th. jarbua gebaut.
1.
At a length of 3–5 cm tigerfish (Therapon jarbua) are gregarious and show schooling. Sometimes individuals choose hiding places which they defend against other tigerfish. During that period they are particularly aggressive and show a special aggressive-coloration: the three stripes along the body are paler and the eyes are darker than under normal circumstances. Schooling fish demonstrate sometimes the aggressive-coloration as well and are more aggressive against other tigerfish.
2.
In swimming around the young Therapon show a high acoustical activity and two types of sounds can be distinguished: Frequently occurring drumming-sounds and longer ones of higher intensity. The latter are used when the tigerfish attack or threaten other individuals. They will be called threatening-sounds.
3.
When the fish are 9–15 cm in length they live solitarily and attack other tigerfish incessantly if the living space is not too small. During the attacks sound production plays an important role. Depending upon the vehemence of the attacks an attacking fish produces either a rapid series of drumming-sounds, or drumming-sounds with an inserted threatening-sound, or a single threatening-sound. The signals are often accompanied by threatening gestures. The fish attacks with the mouth open and the gill covers stretched out. An attacked individual lifts the anterior dorsal fin, swims away and usually produces some drumming-sounds.
4.
The drumming-sounds are for communication among tigerfish. When the fish live solitarily the sound production is extremely low. When two or more fish are brought together the sound production starts at once and reaches a high level within 30 minutes. Also blinded fish produce sounds and answer drumming-sounds of other tigerfish.
5.
The drumming-sounds of the youngest Therapon consist of two components. When the fish grow the second disappears more and more, because the damping of the resonator diminishes. Then the spectrum and intensity of the drumming-sounds changes, too. In 34 mm long fish the highest intensity is at 800 c.p.s., in 10 mm long fish at 650 c.p.s. The spectrum is continuous. The intensity of the sounds rises with the length of the fish.
6.
The threatening-sounds consist of very rapid series of single pulses. The repetition rate can amount to 200 pulses/s. The duration of the threatening-sounds depends on the number of pulses. The stronger a fish threatens the longer are the threatening-sounds. The amplitude of the pulses within a threatening-sound diminishes rapidly. The continuous spectrum is wide with no striking maximum of intensity. When threatening-sounds are played back, the mood of aggression of other tigerfish rises, they produce threatening-sounds themselves and attack other fish.
7.
Water temperature affects the sound production of the tigerfish. At 30 to 33 C it is very high and drops already at 25 C and still more strikingly at 20 C. At the same time the character of the threatening-sounds changes, too. At a rise of the water temperature from 20 to 30 C the pulse repetition rate is doubled.
8.
Changes of light intensity influence the sound production considerably. The fish are almost completely silent in darkness and start producing sounds instantaneously when light is turned on. Sound production lasts during the light period and disappears soon after the light is turned off. When fish are kept in complete darkness, they react with sound production to very small light densities, but these densities are not sufficient to stimulate sound production during a light period of several hours.
9.
The sounds are produced by the contractions of two muscles, which are attached to the shoulder girdle and the air bladder. The fish are able to produce sounds with only one muscle. These drumming muscles appear in the first year of life, when the fish are 27–40 mm in length. Males as well as females are able to produce sounds.
10.
Each muscle consists of three sections. Each of which contains numerous muscle fibers, which measure 2–27 , mostly 17–20 in diameter. The muscle fibers are rich in plasma but lack red color. Their fibrillae form bands or circles. The drumming muscles are innervated by the first spinal nerve. The refractory period is less than 2 ms. The muscles react with single contractions to stimuli up to 150 stimuli/s and proceed to smooth tetanus when the stimulating frequency is 290 or more stimuli/s. From 150 to 290 stimuli/s the contractions are of a tetanic nature, but there is no smooth tetanus. The drumming muscles get quickly tired.
11.
The species Therapon theraps, which is related to Th. jarbua, is also able to produce sounds. The characteristics of these sounds are similar to those of the drumming-sounds of Th. jarbua. They are produced when the fish attack other individuals. I could not find acoustical signals which are adequate to the threatening-sounds of Th. jarbua. Th. theraps possesses the same sound producing mechanism as Th. jarbua.
Many complex behaviours, like speech or music, have a hierarchical organization with structure on many timescales, but it is not known how the brain controls the timing of behavioural sequences, or whether different circuits control different timescales of the behaviour. Here we address these issues by using temperature to manipulate the biophysical dynamics in different regions of the songbird forebrain involved in song production. We find that cooling the premotor nucleus HVC (formerly known as the high vocal centre) slows song speed across all timescales by up to 45 per cent but only slightly alters the acoustic structure, whereas cooling the downstream motor nucleus RA (robust nucleus of the arcopallium) has no observable effect on song timing. Our observations suggest that dynamics within HVC are involved in the control of song timing, perhaps through a chain-like organization. Local manipulation of brain temperature should be broadly applicable to the identification of neural circuitry that controls the timing of behavioural sequences and, more generally, to the study of the origin and role of oscillatory and other forms of brain dynamics in neural systems.
Acoustic communication in Gryllus firmus is temperature-coupled: temperature induces parallel changes in male calling song temporal pattern, and in female preference for song. Temperature effects on song production and recognition networks were localized by selectively warming head or thorax or both head and thorax of intact crickets, then eliciting aggression song production (males) or phonotaxis to synthetic calling song (females). Because male song is produced by a thoracic central pattern generator (CPG), and because head ganglia are necessary for female song recognition, measurements of female phonotaxis under such conditions may be used to test the following competing hypotheses about organization of the song recognition network: 1. A set of neurons homologous to the male song CPG exist in the female, and are used as a template that determines preferred values of song temporal parameters for song pattern recognition (the common neural elements hypothesis), and 2. temporal pattern preference is determined entirely within the head ganglia. Neither selective warming of the head nor of the thorax was effective in changing female song preference, but simultaneous warming of head and thorax shifted preference toward a faster song in most preparations, as did warming the whole animal by raising ambient temperature. These results suggest that phonotactic preference for song temporal pattern is plurisegmentally determined in field crickets. Selective warming experiments during aggression song production in males revealed that syllable period is influenced but not completely determined by thoracic temperature; head temperature is irrelevant. The song CPG appears to receive some rate-setting information from outside the thoracic central nervous system.
In one species of vocalizing (sonic) fish, the midshipman (Porichthys notatus), there are two classes of sexually mature males--Types I and II--distinguished by a number of traits including body size, gonad size, and reproductive tactic. The larger Type-I males (unlike Type-II males and females) build nests, guard eggs, and generate several types of vocalizations. Sound production by Type-I males is paralleled by a proportionate increase of 600% in their sonic muscle mass. The motor volley from ventral occipital roots innervating the sonic muscles establishes their contraction rate and, in turn, the fundamental frequency of emitted sounds. Electrical stimulation of the midbrain in every male and female elicited a rhythmic sonic discharge as recorded in the occipital roots; however, the fundamental frequency was slightly, but significantly, higher (20%) in Type-I males. Intracellular recording from identified motoneurons and presumed presynaptic "pacemaker" neurons showed their synaptic and action potentials had the same frequency as that of the nerve volley in every male and female. Reconstructions of physiologically identified motoneurons and pacemaker neurons following intracellular horseradish-peroxidase (HRP) filling showed their somata and dendrites to be 100-300% larger in Type-I males. These data unambiguously show that the size of a target muscle is correlated with the size of both the respective motoneurons and their presynaptic afferent neurons. As discussed, this implies that the dramatic increase in neuron size in the sonic motor system of Type-I males is causally dependent upon expansion of the sonic muscle. It is further likely that the more modest sex difference in the rhythmic central discharge is established by the intrinsic membrane properties of sonic neurons. These results also corroborate, at a number of behavioral, morphological, and neurophysiological levels, that the sonic motor system of "sneak spawning" Type-II males is similar to that of females. Thus, unlike the vocalizing Type-I males, sexual differentiation of the reproductive system in Type-II males is not linked to concomitant changes in the neurophysiological and morphological features of the sonic motor circuit.
Rates of force development, contraction and relaxation of vertebrate skeletal muscle are temperature dependent with Q10 values of approximately 2. Maximal forces developed have a low or negative thermal dependence. The functional basis of these patterns is poorly understood. Muscle performance generally does not acclimate. There appears to have been some evolutionary adaptation among species and classes to different thermal regimes, such that muscles from cold-adapted species maintain better mechanical performance at low temperatures than do those from warm-adapted animals. However, rate processes remain strongly thermally dependent even in animals with low or variable body temperatures. This thermal dependence of muscle in vitro is reflected in behavioural performance: maximal force generation in vivo is temperature independent and time-dependent activities are more rapid at higher muscle temperatures.
An analysis of the natural bioacoustic signals made by two closely related African fishes (P. adspersus and P. isidori) revealed that these species separated along several acoustic dimensions that are likely to be important for species isolation. Both species produced grunts that were composed of a trains of pulses, but the pulse repetition rates were distinctly different (56 +/- 3 s.d. vs 44 +/- 4 s.d. pps). Complex tone bursts (moans) were also used, but the species differed substantially in the location of the fundamental peak (240 Hz +/- 12 s.d. vs 332 Hz +/- 34 s.d.). Some P. adspersus males sustained these tones for over a second (812 ms +/- 495 s.d.), whereas P. isidori produced shorter tones (121 ms +/- 35 s.d.). During interactions with females, the two species produced the grunts and moans in distinct species-typical patterns: P. adspersus males alternated grunts with moans and P. isidori produced a single grunt followed by a succession of moans. A detailed analysis of identified individual P. adspersus showed that acoustic features constituted individual signatures which could be used by conspecifics to identify individuals. Grunt spectral peak frequency was shown to be a good predictor of male mass, with peak frequency decreasing at 72 Hz per gram. Simulated standardized courtship encounters with females revealed that males differ markedly in their apparent ability to produce sustained moans and it is suggested that this may be particularly important to females in mate selection.