摘要: Acoustic communication signals are important for species recognition and mate attraction across numerous taxa. For instance, most of the thousands of species of frogs have a species-specific advertisement call that females use to localize and discriminate among potential mates. Thus, the acoustic structure of the advertisement call is critical for reproductive success. The acoustic structure of calls will generally diverge over evolutionary time and can be influenced by the calls of sympatric species. While many studies have shown the influence of geography on contemporary call variation in populations of frogs, no study has compared the acoustic structure of frog calls across many species to ask whether we can detect an influence of divergence time and overall geographic overlap on the differences in acoustic structure of species-typical calls that we observe now. To this end, we compared acoustic features of the calls of 225 species of frogs within 4 families. Furthermore, we used a behavioral assay from 1 species of frog to determine which acoustic features to prioritize in our large-scale analyses. We found evidence that both phylogeny (time) and geography (place) relate to advertisement call acoustics albeit with large variation in these relationships across the 4 families in the analysis. Overall, these results suggest that, despite the many ecological and evolutionary forces that influence call structure, the broad forces of time and place can shape aspects of advertisement call acoustics.

摘要: Wetlands are unique ecological environments capable of harboring high biodiversity. However, urbanization can degrade, eliminate, or transform these habitats. Although amphibians utilize habitats created by humans in urban landscapes, few studies have investigated the influence of the habitat quality on the life history of anurans. We assessed life history traits such as snout-vent length (SVL), body condition, and reproductive investment in the South American common toad Rhinella arenarum, to determine whether urbanization is harmful or beneficial to this species. We sampled wetlands with different levels of urbanization in R & iacute;o Cuarto city, C & oacute;rdoba, Argentina. We recorded males with lower SVL in medium urbanized wetlands and those with the highest SVL in both low and high urbanization categories, similar to what was found for body conditions with males with low body conditions inhabiting wetlands with a medium degree of urbanization. In females, lower SVL was recorded in medium urbanization and highest SVL in high and low urbanization. It is observed that females recorded in highly urbanized wetlands have a very low body condition. The reproductive investment parameters were not significantly different, but we observed an association between a greater number of eggs and clutch size with wetlands of low urbanization. These results show a variability of responses of R. arenarum to urbanization, which could be due to phenotypic plasticity in its life history parameters, allowing it to inhabit urban areas. Continuous monitoring of the species in these wetlands is needed to determine if these biological responses are temporary or persistent.

摘要: Dispersal is an important individual decision which may influence individual fitness as well as population viability. The social cohesion hypothesis posits more social individuals remain at home, which is supported by prior work across taxa. However, how the sociality and connectivity of the group an individual resides in-their group social structure-relates to dispersal decisions has not been explored. We extend the social cohesion hypothesis to predict individuals residing in more social groups would remain at home, and we quantified the affiliative and agonistic social network structure of female yellow-bellied marmots (Marmota flaviventer), a facultatively social ground-dwelling squirrel, where about half of all females disperse. Using mixed-effects models, we found no support for the hypothesis that affiliative group structure explained any variation in a marmot's decision to disperse. We did find marmots in groups with less agonistic centralization (around one or few individuals) were less likely to disperse. The former finding may result from limited ability to perceive group structure whereas the latter may reflect individuals in less agonistically centralized groups are less likely to be reproductively suppressed. These results suggest individual dispersal decisions are more impacted by individual sociality and not that of their social group. Thus, the social cohesion hypothesis may not scale to the level of the group. Further work is required to determine whether dispersal decisions in obligately social species are influenced by group social structure.

摘要: The nutritional status of an individual can significantly influence its life history traits, including development, growth, reproduction, and survival. In the predatory mite Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae), the plasticity of life history traits, such as developmental time and size at maturity, is influenced by the quality and quantity of food. This study aimed to investigate the effects of dietary restriction at different life stages (i.e., juvenile, early adulthood, and later adulthood) on the lifespan and fecundity of P. persimilis. We found that reduced dietary intake during early adulthood resulted in a shorter lifespan for both male and female P. persimilis. Furthermore, this study demonstrated a sex-specific response to dietary restriction: it extended the lifespan of males but reduced that of females during later adulthood. Diet restriction during the postovipositional period of females showed the most variable life history trait response. Our results showed that the impact of diet restriction at different life stages can have combined influences on the postovipositional duration of P. persimilis, where the individuals receiving diet restriction during immature development and early adulthood had a greater reduction in ovipositional duration as those experiencing diet restriction during late adulthood. In addition, we observed a positive correlation between the lifespan and fecundity of females, with higher prey availability increasing both. The insights obtained from our research contribute to a better understanding of the aging process and dietary requirements of P. persimilis, which can facilitate the development of more effective biological control strategies using this predator for spider mites in agriculture.

摘要: Animal coloration has a wide range of biological functions and may be subject to different, sometimes conflicting, selective pressures. In crustaceans, the evolution of coloration is relatively unstudied, despite the broad range of colors and color patterns, which includes variability at multiple levels. Freshwater crayfish are known to show color variability within species and populations, as well as intra-individual variability, but the function, if any, of crayfish coloration is largely unknown. Here, I report on an experiment to understand patterns of color variability in the crayfish Faxonius virilis and show that variation is strongly correlated to ontogenetic changes from a summer non-reproductive form to a fall reproductive form. Crayfish showed comparatively little inter- and intra-individual color variation in their non-reproductive form, but substantial variation at both levels in the reproductive form. Transition to the reproductive form was associated with the development of greener or bluer coloration localized to the chelae on a subset of individuals, but these changes showed no clear correlation with sex or body size. Future investigations should focus on determining whether differences in color between individuals in the mating season are associated with any physiological or behavioral differences, or with differential susceptibility to predation.

摘要: Same-sex mounts provide male juvenile golden snub-nosed monkeys (Rhinopithecus roxellana) with opportunities to practice heterosexual copulatory skills and are often followed by grooming (post-mounting grooming, PMG). We hypothesized that juveniles acted as the mountee and provided mounting opportunities to receive grooming from their peer mounter. Here, we observed same-sex mounts among male juveniles (N = 5) in a captive group of R. roxellana in Shanghai Wild Animal Park, China, from November 2014 to June 2015. Among 1,044 mounts recorded, 45.40% were accompanied by PMG initiated by the mounter and only 3.74% were followed by PMG initiated by the mountee. Mountees were more likely to receive PMG when they performed a mounting solicitation than when they did not, or when they were mounted for a longer time (even if they did not solicit). Over a long timeframe (1 month), mountee's tended to choose partners who groomed them more often than others after mounting, regardless of how long the grooming lasted. However, whether the mounter groomed the mountee did not predict the mounting direction in their subsequent mount. Our results suggest that, in the context of same-sex mounts, juveniles provide mounting opportunities to receive grooming from peers on a long-term, rather than on a short-term basis. This study provides the first evidence that juveniles' same-sex mounting strategy may be associated with the grooming market in nonhuman primates, which necessitates further investigation with large free-ranging groups due to the limited sample size of individuals and the captive setting of the current study.

摘要: How ecological and evolutionary factors affect small mammal diversity in arid regions remains largely unknown. Here, we combined the largest phylogeny and occurrence dataset of Gerbillinae desert rodents to explore the underlying factors shaping present-day distribution patterns. In particular, we analyzed the relative contributions of ecological and evolutionary factors on their species diversity using a variety of models. Additionally, we inferred the ancestral range and possible dispersal scenarios and estimated the diversification rate of Gerbillinae. We found that Gerbillinae likely originated in the Horn of Africa in the Middle Miocene and then dispersed and diversified across arid regions in northern and southern Africa and western and central Asia, forming their current distribution pattern. Multiple ecological and evolutionary factors jointly determine the spatial pattern of Gerbillinae diversity, but evolutionary factors (evolutionary time and speciation rate) and habitat filtering were the most important in explaining the spatial variation in species richness. Our study enhances the understanding of the diversity patterns of small mammals in arid regions and highlights the importance of including evolutionary factors when interpreting the mechanisms underlying large-scale species diversity patterns.

摘要: The nonlinearity and fear hypothesis predicts that highly aroused vocal mammals and birds produce vocalizations (notably alarm calls and screams) which contain a variety of nonlinear phenomena (NLP). Such vocalizations often sound noisy because vocal production systems are over-blown when animals are highly aroused. While much is known about the conditions under which animals produce vocalizations containing NLP and how species respond to them, there is little research about the heritability of such behavioral traits. Using the quantitative genetic animal model, we estimated the genetic basis of noise in alarm calls produced by females and found significant heritability in call entropy-our measure of the noisiness. About 9% of the variance in noisiness can be accounted for by genetic differences. Taken together, these findings suggest that the degree to which marmots produce noisy calls is modestly heritable and can be thus subject to further evolution via natural selection.

摘要: Captive breeding and stocking are commonly employed strategies for enhancing fisheries and conserving endangered fish species. However, hatchery-raised fish often exhibit reduced performance in the wild, displaying alterations in physiological, morphological, and behavioral traits. We tested for differences in swimming capacity and metabolic traits between wild and hatchery-reared individuals of the Spanish toothcarp (Aphanius iberus) from 2 different populations. Furthermore, we experimentally tested if these changes translated into fitness differences after their stocking into the wild. There were significant differences in swimming capacity and metabolic traits between wild and hatchery-reared individuals and also between the 2 populations. Captive-bred individuals displayed consistently lower metabolic rates than wild individuals from the same population (30-76% lower). Critical swimming speed rather differed between the 2 populations. Sex-specific differences were observed in maximum and standard metabolic rates, with wild individuals and females generally exhibiting higher values but with some exceptions. During a 3-month experiment, survival rates did not significantly differ between wild and captive-bred fish. Captive-bred individuals started smaller but exhibited rapid growth during the experiment. Initially, larger captive-bred fish had lower body conditions than their wild counterparts, but these differences progressively diminished. In summary, captive-bred individuals of this fish species showed lower metabolic rates, although the differences with wild individuals slightly depended on sex and size.

摘要: Juveniles of interspecific avian brood parasites need to locate and recognize conspecifics to continue their life cycle after being reared by individuals of another species. However, little is known about the recognition mechanisms and cues involved in this critical stage of their lives. It has been proposed that adult parasites could show some kind of parental behavior by actively searching and interacting with conspecific young, which in turn could serve the juveniles to learn and/or reinforce the learning of conspecific characteristics. Since acoustic communication is one of the main channels used by birds, if such form of parental behavior by adult avian brood parasites does exist, adult cowbirds should recognize and respond positively to vocalizations of conspecific juveniles. We experimentally tested whether adult shiny Molothrus bonariensis and screaming M. rufoaxillaris cowbirds respond positively towards acoustic signals of conspecific juveniles using two playback experiments, one conducted in semi-captivity and the other in the field. In both cases, we presented 3 types of playbacks to adults of both cowbird species: vocalizations of shiny cowbird juveniles, vocalizations of screaming cowbird juveniles, and white noise as a control. In the experiment in semi-captivity, no significant differences were found between treatments. In the field experiment, no conspecifics approached the playback area, but hosts of the species whose playback was played were attracted to the loudspeaker. In conclusion, our results do not support the predictions we tested from the parental behavior hypothesis and indicate that adult shiny and screaming cowbirds do not respond positively to acoustic signals of conspecific juveniles, at least not to the type of signals used in our experiments.