Intraspecific and intraspecific views of colour signals in the strawberry poison frog Dendrobates Pumilio

Poison frogs in the anuran family Dendrobatidae use bright colors on their bodies to advertise toxicity. The species Dendrobates pumilio Schmidt 1858, the strawberry poison frog, shows extreme polymorphism in color and pattern in Panama. It is known that females of D. pumilio preferentially choose mates of their own color morph. Nevertheless, potential predators must clearly see and recognize all color morphs if the aposermatic signaling system is to function effectively. We examined the ability of conspecifics and a model predator to discriminate a diverse selection of D. pumilio colors from each other and from background colors. Microspectrophotometry of isolated rod and cone photoreceptors of D. pumilio revealed the presence of a trichromatic photopic visual system. A typical tetrachromatic bird system was used for the model predator. Reflectance spectra of frog and background colors were obtained, and discrimination among spectra in natural illuminants was mathematically modeled. The results revealed that both D. pumilio and the model predator discriminate most colors quite well, both from each other and from typical backgrounds, with the predator generally performing somewhat better than the conspecifics. Each color morph displayed at least one color signal that is highly visible against backgrounds to both visual systems. Our results indicate that the colors displayed by the various color morphs of D. pumilio are effective signals both to conspecifics and to a model predator.

Parallel evolution of sexual isolation in sticklebacks

Mechanisms of speciation are not well understood, despite decades of study. Recent work has focused on how natural and sexual selection cause sexual isolation. Here, we investigate the roles of divergent natural and sexual selection in the evolution of sexual isolation between sympatric species of threespine sticklebacks. We test the importance of morphological and behavioral traits in conferring sexual isolation and examine to what extent these traits have diverged in parallel between multiple, independently evolved species pairs. We use the patterns of evolution in ecological and mating traits to infer the likely nature of selection on sexual isolation. Strong parallel evolution implicates ecologically based divergent natural and/or sexual selection, whereas arbitrary directionality implicates nonecological sexual selection or drift. In multiple pairs we find that sexual isolation arises in the same way: assortative mating on body size and asymmetric isolation due to male nuptial color. Body size and color have diverged in a strongly parallel manner, similar to ecological traits. The data implicate ecologically based divergent natural and sexual selection as engines of speciation in this group.

Dissecting the complex genetic basis of mate choice

The genetic analysis of mate choice is fraught with difficulties. Males produce complex signals and displays that can consist of a combination of acoustic, visual, chemical and behavioural phenotypes. Furthermore, female preferences for these male traits are notoriously difficult to quantify. During mate choice, genes not only affect the phenotypes of the individual they are in, but can influence the expression of traits in other individuals. How can genetic analyses be conducted to encompass this complexity? Tighter integration of classical quantitative genetic approaches with modern genomic technologies promises to advance our understanding of the complex genetic basis of mate choice.

Patterns of painting in satin bowerbirds Ptilonorhynchus violaceus and males' responses to changes in their paint

Satin bowerbirds Ptilonorhynchus violaceus have an elaborate multi-component sexual display, some components of which have been extensively studied. We describe a relatively unstudied component of this display, bower painting, and birds' responses to manipulations of their paint. Males of this species focus their display around a stick bower constructed on the forest floor which they decorate with a variety of objects and paint. Painting involves a male masticating plant material and wiping the plant-saliva mixture onto the inside walls of the bower; during courtship visits to bowers, females nibble at this paint. We found that 93% of 53 males painted their bowers at our study site and the time males spent painting their bowers accounted for 24% of their time at the bower. We experimentally removed and added paint to bowers to test whether males respond to these changes in their paint. Males gave more advertisement calls and spent less time manipulating sticks at the bower when we added fresh wet paint to their bowers compared to older dried paint or a control treatment. They did not respond to the removal of paint from their bowers, perhaps because it was primarily older dried paint that was removed. We also found that males painted more frequently when there was measurable wind in their bowers, which could have degraded the quality of the signal. Our findings indicate that fresh wet paint is more important to males than older dried paint and, together with previous work at this site, suggest that paint may act as a signal to females. Given that females nibble bower sticks during courtship, we suggest that bower paint may function as a chemical sexual signal rather than a visual signal.

Interactions between behaviour and plasma steroids within the scramble mating system of the promiscuous green turtle, Chelonia mydas

We measured plasma androgen (combined testosterone and 5 alpha-dihydrotestosterone) (A) and corticosterone (B) in the promiscuous green turtle (Chelonia mydas) during courtship in the southern Great Barrier Reef. This study examined if reproductive behaviors and intermale aggression induced behavioral androgen and adrenocortical responses in reproductively active male and female green turtles. Associations between reproductive behavior and plasma steroids were investigated in green turtles across the population and within individuals. Levels across a range of both asocial and social behaviors were compared including (a) free swimming behavior; (b) initial courtship interactions; (c) mounted behavior (male and female turtles involved in copulatory activities); (d) intermale aggression (rival males that physically competed with another male turtle or mounted males recipient to these aggressive interactions); and (e) extensive courtship damage (male turtles that had accumulated excessive courtship damage from rival males). Behavioral androgen responses were detected in male turtles, in that plasma A was observed to increase with both attendant and mounted behavior. Male turtles who had been subjected to intermale aggression or who had accumulated severe courtship damage exhibited significantly lower plasma A than their respective controls. No pronounced adrenocortical response was observed after either intermale aggression or accumulation of extensive courtship damage. Female turtles exhibited a significant increase in plasma B during swimming versus mounted behavior, but no change in plasma A. We discuss our results in terms of how scramble polygamy might influence behavioral androgen interactions differently from more typical combative and territorial forms Of male polygamy. (C) 1999 Academic Press.

Ecologia de comunidades e comportamento reprodutivo de anfíbios anuros em savana amazônica

The Amazon savannas occur as isolated patches throughout extensive areas of forest in the states of Amapá, Amazonas, Pará, and Roraima. There is a considerable variation in the composition of anuran assemblages in the localities and phytophysiognomies of Amazon savannas and given the absence of studies on reproductive behavior, a systematic and geographically wide sampling has been carried out in the Amapá savanna, located in the Eastern Amazon. The study was conducted in a savanna area in the state of Amapá to examine the composition, ecology, and reproductive behavior of anuran amphibians. We carried out 24 field trips in each phytophysiognomy (gramineous-woody savana, gramineous-herbaceous-woody savana, park savana, and arboreal savanna); for analysis of reproductive behavior observations were made during the period January to December 2013, lasting four consecutive days. Samples were collected by active and acoustic search along 20 plots of 100x50 meters. Twenty-one anuran species were recorded, of which four are new records for the state of Amapá: Dendropsophus walfordi, Scinax fuscomarginatus, Pseudopaludicola boliviana e Elachistocleis helianneae. The KruskalWallis ANOVA revealed significant differences between richness and species diversity in the phytophysiognomies (p < 0.05). The Bray-Curtis similarity coefficient divided the phytophysiognomies into three groups: arboreal savana, gramineous-woody savanna and gramineous-herbaceous-woody savanna, and park savanna. According to the non-metric multidimensional scaling, the structure of the anuran community resulted in a separation into three phytophysiognomies, with significant differences in the structure of communities (ANOSIM, R = 0.823; p < 0.001). In the study of community ecology, the results obtained for spatial, temporal, and trophic niche breadth suggest that the assemblage of anurans of the Amapá savanna is not composed of predominantly generalist species. Also, the presence of other specialist anurans may explain the processes of speciation associated with the isolation of habitats, resulting in heterogeneity and spatial discontinuity in the phytophysiognomies with open formations. The null model analysis revealed that the community is structured based on temporal and trophic niche, indicating a significant influence of contemporary ecological factors on the assemblage. The absence of structure based on spatial niche might be explained by the spatial segregation in the distribution and occupation of anurans in the different phytophysiognomies of the Amapá savanna. Regarding the reproductive behavior of anurans, 11 species were classified as having a long breeding season, intrinsically associated with the rainy season and the reproductive mode of most species that lay egg clutches in lentic water bodies. Six reproductive modes were recorded and parental care was observed in Leptodactylus macrosternum and L. podicipinus, whose reproductive mode is characterized by foam nests. Regarding behavioral reproductive strategies, calling males were observed in all species of anurans, satellite males were recorded only for D. walfordi, Hypsiboas multifasciatus, S. nebulosus and S. fuscomarginatus; active search for females was observed for Phyllomedusa hypochondrialis and L. fuscus, and male displacement was recorded only for Rhinella major and R. margaritifera. Of the reproductive behaviors observed, throat and vocal sac display is associated with courtship and territorial behavior exhibited by males. In addition to courtship behavior, visual signals associated with courtship strategies were recorded for the anurans of the Amapá savanna.

The Diary of Mary McKeon, an Irish American Domestic Servant in Nineteenth Century America

What did young, single, unaccompanied Irish women experience when immigrating to the United States in the late nineteenth century? In this final project, I will explore primary and secondary sources that address their experiences, focusing on a diary written in 1883 by a young Irish domestic servant working in New Haven, Connecticut. Mary McKeon, a sixteen-year-old girl from County Leitrim, Ireland, recorded her experiences as a domestic servant for two different families, as well as her own personal thoughts. Mary wrote down her personal experiences, providing a glimpse of what her life was like both inside and outside of her employer’s home. Though much of my research will show that many young women like Mary would be subjected to prejudice and discrimination due to their lack of understanding middle-class American values, which would give rise to the “Bridget” stereotype of a brutish, ill-mannered and incompetent domestic servant, not all Irish women experienced that discrimination and prejudice. Mary is one example of a domestic servant that was treated kindly by her employers and her story documents a more positive and supportive environment for this newly arrived young, single immigrant. Her diary also reveals her to be a young woman who worked to improve her language skills and her situation. And, through her diary, we get a glimpse of her strategies for ensuring an active social life, including access to courtship and marriage. By analyzing Mary’s diary and sharing my results in this final project, I hope to provide a more comprehensive view into the lives of these young women.

Experimental demonstration of possible cryptic female choice on male tsetse fly genitalia

artículo -- Universidad de Costa Rica. Escuela de Biología, 2009. Este documento es privado debido a restricciones de derechos de autor del publicador.

Sex group composition, social interaction, and metabolism in the fish Nile tilapia

O objetivo deste trabalho foi testar se grupos monossexuais de machos gastam mais energia e exibem perfil agonístico diferente de grupos formados por um macho e uma fêmea na tilápia-do-Nilo (Oreochromis niloticus). Tais diferenças são esperadas, pois machos e fêmeas competem por diferentes recursos reprodutivos. Foram utilizadas duplas de machos (MM) e duplas de macho-fêmea (MF) que permaneceram pareadas por 40 minutos. Durante esse período foi feito o registro da interação agonística (10 minutos iniciais e 10 minutos finais do pareamento) e determinado o gasto energético (consumo de O2) pelo Método de Winckler. A latência para o início dos confrontos (média ± DP, MM = 27,40 ± 25,15 s; MF = 14,22 ± 21,19 s; Mann-Whitney, U = 33,50, P = 0,21) e a freqüência de todas as unidades comportamentais (média ± DP, MM < 72,30 ± 25,29; MF < 73,50 ± 21,65.10/min; Mann-Whitney, P > 0,10) foram semelhantes entre os grupos MM e MF nos 10 minutos iniciais. Isso indica que cada intruso foi considerado um potencial competidor no início da interação. No entanto, a freqüência de ondulação (interação também exibida durante a corte) foi maior para o residente do grupo MF nos 10 minutos finais (média ± DP, MM = 3,56 ± 5,89; MF = 8,56 ± 4,00.10/min; Mann-Whitney, U = 15,50, P = 0,01). A freqüência de fuga, entretanto, foi menor para o intruso do mesmo grupo (média ± DP, MM = 3,90 ± 4,33; MF = 0,44 ± 0,96.10/min; Mann-Whitney, U = 23,50, P = 0,04). Além disso, o perfil agonístico no grupo MM foi composto por um maior número de itens comportamentais do que o MF (para residentes e intrusos). Apesar das diferenças comportamentais, o consumo de O2 não foi afetado pela composição sexual do grupo (média ± DP, MM = 1,93 ± 0,54; MF = 1,77 ± 0,46 mgO2.g peso seco-1.40/min; t-teste de Student, t = 0,71, P = 0,49).

Stress-induced peak (but not resting) metabolism correlates with mating display intensity in male guppies

Recent empirical and conceptual papers have highlighted the potential for metabolism to act as a proximate mechanism for behavior that could explain animal personality (consistency over time). Under this hypothesis, individuals with consistently high levels of behavioral activity should also have high resting metabolic rate (RMR) as it can reflect capacity to process food and generate energy. We tested for the predicted positive covariance between RMR and three behaviors that differ in energy demands in 30 male guppies, using multivariate mixed models; we repeatedly measured their activity (10 times each), courtship displays (nine times), voracity (10 times), and metabolism (four-times). Resting metabolic rate (measured overnight in respirometry trials) did not consistently differ among males, whereas initial peak metabolism measured during those same trials (R = 0.42), and all behaviors were repeatable (R = 0.33–0.51). RMR declined over time suggesting habituation to the protocol, whereas peak metabolism did not. Initial peak metabolism was negatively correlated with courtship display intensity, and voracity was positively correlated with activity, but all other among-individual correlations were not significant. We conclude that RMR does not provide a proximate explanation for consistent individual differences in behavior in male guppies, and therefore the potential for independent evolution of these physiological and behavioral traits seems possible. Finally, we identify peak metabolism as a potential measure of the stress response to confinement, which highlights the value of considering various aspects of metabolic rates recording during respirometry trials.

A new semi-automated method for assessing avian acoustic networks reveals that juvenile and adult zebra finches have separate calling networks

Social networks are often inferred from spatial associations, but other parameters like acoustic communication are likely to play a central role in within group interactions. However, it is currently difficult to determine which individual initiates vocalizations, or who responds to whom. To this aim, we designed a method that allows analyzing group vocal network while controlling for spatial networks, by positioning each group member in equidistant individual cages and analyzing continuous vocal interactions semi-automatically. We applied this method to two types of zebra finch groups, composed of either two adult females and two juveniles, or four young adults (juveniles from the first groups). Young often co-occur in the same social group as adults but are likely to have a different social role, which may be reflected in their vocal interactions. Therefore, we tested the hypothesis that the social structure of the group influences the parameters of the group vocal network. We found that groups including juveniles presented periods with higher level of activity than groups composed of young adults. Using two types of analyses (Markov analysis and cross-correlation), we showed that juveniles as well as adults were more likely to respond to individuals of their own age-class (i.e. to call one after another, in terms of turn-taking, and within a short time-window, in terms of time delay). When juveniles turned into adulthood, they showed adult characteristics of vocal patterns. Together our results suggest that vocal behavior changes during ontogeny, and individuals are more strongly connected with individuals of the same age-class within acoustic networks.

An integrative multidisciplinary approach to understanding cryptic divergence in Brazilian species of the Anastrepha fraterculus complex (Diptera: Tephritidae).

An integrative multidisciplinary approach was used to delimit boundaries among cryptic species within the Anastrepha fraterculus complex in Brazil. Sexual compatibility, courtship and sexual acoustic behaviour, female morphometric variability, variation for the mitochondrial gene COI, and the presence of Wolbachia were compared among A. fraterculus populations from the Southern (Vacaria, Pelotas, Bento Gonçalves, S~ao Joaquim) and Southeastern (Piracicaba) regions of Brazil. Our results suggest full mating compatibility among A. fraterculus populations from the Southern region and partial pre-zygotic reproductive isolation of these populations when compared with the population from the Southeastern region. A. fraterculus populations from both regions differed in the frequency of courtship displays and aspects of the calling phase and mounting acoustic signal. Morphometric analysis showed differences between Southern region and Southeastern region samples. All populations analyzed were infected with Wolbachia. The trees generated from the COI sequencing data are broadly congruent with the behavioural and morphometric data with the exception of one Southern population. The likely mechanisms by which A. fraterculus populations might have diverged are discussed in detail based on behavioural, morphometric, molecular genetics, and biogeographical studies