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In this innovative celebration of diversity and affirmation of individuality in animals and humans, Joan Roughgarden challenges accepted wisdom about gender identity and sexual orientation. A distinguished evolutionary biologist, Roughgarden takes on the medical establishment, the Bible, social science—and even Darwin himself. She leads the reader through a fascinating discussion of diversity in gender and sexuality among fish, reptiles, amphibians, birds, and mammals, including primates. Evolution's Rainbow explains how this diversity develops from the action of genes and hormones and how people come to differ from each other in all aspects of body and behavior. Roughgarden reconstructs primary science in light of feminist, gay, and transgender criticism and redefines our understanding of sex, gender, and sexuality. Witty, playful, and daring, this book will revolutionize our understanding of sexuality. Roughgarden argues that principal elements of Darwinian sexual selection theory are false and suggests a new theory that emphasizes social inclusion and control of access to resources and mating opportunity. She disputes a range of scientific and medical concepts, including Wilson's genetic determinism of behavior, evolutionary psychology, the existence of a gay gene, the role of parenting in determining gender identity, and Dawkins's \"selfish gene\" as the driver of natural selection. She dares social science to respect the agency and rationality of diverse people; shows that many cultures across the world and throughout history accommodate people we label today as lesbian, gay, and transgendered; and calls on the Christian religion to acknowledge the Bible's many passages endorsing diversity in gender and sexuality. Evolution's Rainbow concludes with bold recommendations for improving education in biology, psychology, and medicine; for democratizing genetic engineering and medical practice; and for building a public monument to affirm diversity as one of our nation's defining principles.

We show that reproductively mature male sea lampreys release a bile acid that acts as a potent sex pheromone, inducing preference and searching behavior in ovulated female lampreys. The secreted bile acid 7α,12α,24-trihydroxy-5α-cholan-3-one 24-sulfate was released in much higher amounts relative to known vertebrate steroid pheromones and may be secreted through the gills. Hence, the male of this fish species signals both its reproductive status and location to females by secreting a pheromone that can act over long distances.

ESP22, a new pheromone produced by juvenile mice before puberty and released through the tears, activates neurons in the vomeronasal organ and inhibits mating behaviour in adult males towards animals expressing this signal. Pheromone signal indicates sexual immaturity Social behaviour in rodents is driven by pheromones that signal information on age, gender and physiology to other individuals. Here, Stephen Liberles and colleagues identify a novel pheromone (ESP22) produced by juvenile mice before puberty. Released through the tears, ESP22 activates neurons in the vomeronasal organ and inhibits mating behaviour in adult males towards any animal expressing this signal. Thus, ESP22 seems to be a sign of sexual immaturity that helps to control the sexual behaviour of adult mice. Animals display a repertoire of different social behaviours. Appropriate behavioural responses depend on sensory input received during social interactions. In mice, social behaviour is driven by pheromones, chemical signals that encode information related to age, sex and physiological state 1 . However, although mice show different social behaviours towards adults, juveniles and neonates, sensory cues that enable specific recognition of juvenile mice are unknown. Here we describe a juvenile pheromone produced by young mice before puberty, termed exocrine-gland secreting peptide 22 (ESP22). ESP22 is secreted from the lacrimal gland and released into tears of 2- to 3-week-old mice. Upon detection, ESP22 activates high-affinity sensory neurons in the vomeronasal organ, and downstream limbic neurons in the medial amygdala. Recombinant ESP22, painted on mice, exerts a powerful inhibitory effect on adult male mating behaviour, which is abolished in knockout mice lacking TRPC2, a key signalling component of the vomeronasal organ 2 , 3 . Furthermore, knockout of TRPC2 or loss of ESP22 production results in increased sexual behaviour of adult males towards juveniles, and sexual responses towards ESP22-deficient juveniles are suppressed by ESP22 painting. Thus, we describe a pheromone of sexually immature mice that controls an innate social behaviour, a response pathway through the accessory olfactory system and a new role for vomeronasal organ signalling in inhibiting sexual behaviour towards young. These findings provide a molecular framework for understanding how a sensory system can regulate behaviour.

Background Female reproductive behaviors and physiology change profoundly after mating. The control of pregnancy-associated changes in physiology and behaviors are largely hard-wired into the brain to guarantee reproductive success, yet the gene expression programs that direct neuronal differentiation and circuit wiring at the end of the sex determination pathway in response to mating are largely unknown. In Drosophila , the post-mating response induced by male-derived sex-peptide in females is a well-established model to elucidate how complex innate behaviors are hard-wired into the brain. Here, we use a genetic approach to further characterize the molecular and cellular architecture of the sex-peptide response in Drosophila females. Results Screening for mutations that affect the sensitivity to sex-peptide, we identified the channel nuclear pore protein Nup54 gene as an essential component for mediating the sex-peptide response, with viable mutant alleles leading to the inability of laying eggs and reducing receptivity upon sex-peptide exposure. Nup54 directs correct wiring of eight adult brain neurons that express pickpocket and are required for egg-laying, while additional channel Nups also mediate sexual differentiation. Consistent with links of Nups to speciation, the Nup54 promoter is a hot spot for rapid evolution and promoter variants alter nucleo-cytoplasmic shuttling. Conclusions These results implicate nuclear pore functionality to neuronal wiring underlying the sex-peptide response and sexual differentiation as a response to sexual conflict arising from male-derived sex-peptide to direct the female post-mating response.

Background The rhythmic mating behavior of insects has been extensively documented, yet the regulation of this behavior through sex pheromone sensing olfactory genes affected by the clock genes in the rhythm pathway remains unclear. Results In this study, we investigated the impact of circadian rhythm on female recognition of male rectal Bacillus -produced sex pheromone in B. dorsolis . Behavioral and electrophysiological assays revealed a peak in both mating behavior and response to sex pheromones in the evening in females. Comparative transcriptome analysis of female heads demonstrated rhythmic expression of the Timeless gene-Tim and odorant binding protein gene-Pbp5, with the highest expression levels occurring in the evening. Protein structural modeling, tissue expression patterns, RNAi treatment, and physiological/behavioral studies supported Pbp5 as a sex pheromone binding protein whose expression is affected by Tim. Furthermore, manipulation of the female circadian rhythm resulted in increased morning mating activity, accompanied by consistent peak expression of Tim and Pbp5 during this time period. These findings provide evidence that insect mating behavior can be modulated by clock genes through their effects on sex pheromone sensing processes. Conclusions Our results also contribute to a better understanding of the molecular mechanisms underlying rhythmic insect mating behavior.

Background Gustatory receptors (GRs) are known to mediate responses to various chemical stimuli including sugars and bitter compounds and sex pheromones. Although numerous types of GRs have been identified across insect species, the physiological roles of most GRs remain largely unknown. The silkworm, Bombyx mori , is representative of the order Lepidoptera, which includes over 70% of agriculturally important pest species. A notable feature of GRs in B. mori is that most GRs are organized in clusters, making them highly suitable for large-scale genetic studies. Results Here we developed a transcription activator-like effector nuclease-mediated gene cluster replacement system, enabling functional studies beyond single-gene resolution. Using this system, we deleted the GR27-31 cluster in B. mori, which includes 12 GRs spanning approximately 82 kb of genomic sequence. Loss of GR27-31 function results in significant time retardation of courtship by impairing the ability of male silkmoths to seek female silkmoths. Electroantennogram analysis revealed that GR27-31 mutant male silkmoths did not change their responses to volatile sex pheromones of bombykol and bombykal compared with wild-type silkmoths, indicating that GR27-31 mutation did not affect male–female sex pheromone responses at the peripheral level. Subsequent molecular analysis revealed that mRNA relative expression of serotonin receptors was significantly affected in mutant silkmoths. Conclusions The current study provides the first genetic and phenotypic evidence that GRs modulate male–female courtship in B. mori . Furthermore, the results revealed for the first time that the serotonin pathway is associated with GR regulation of courtship behavior in insects.

The \"good genes\" hypothesis predicts that mating preferences enable females to select mates of superior genetic quality. The genetic consequences of the preference shown by female gray tree frogs for long-duration calls were evaluated by comparing the performance of maternal half-siblings sired by males with different call durations. Offspring of male gray tree frogs that produced long calls showed better performance during larval and juvenile stages than did offspring of males that produced short calls. These data suggest that call duration can function as a reliable indicator of heritable genetic quality.

Background Species interactions can promote mating behavior divergence, particularly when these interactions are costly due to maladaptive hybridization. Selection against hybridization can indirectly cause evolution of reproductive isolation within species, a process termed cascade reinforcement. This process can drive incipient speciation by generating divergent selection pressures among populations that interact with different species assemblages. Theoretical and empirical studies indicate that divergent selection on gene expression networks has the potential to increase reproductive isolation among populations. After identifying candidate synaptic transmission genes derived from neurophysiological studies in anurans, we test for divergence of gene expression in a system undergoing cascade reinforcement, the Upland Chorus Frog ( Pseudacris feriarum ). Results Our analyses identified seven candidate synaptic transmission genes that have diverged between ancestral and reinforced populations of P. feriarum , including five that encode synaptic vesicle proteins. Our gene correlation network analyses revealed four genetic modules that have diverged between these populations, two possessing a significant concentration of neurotransmission enrichment terms: one for synaptic membrane components and the other for metabolism of the neurotransmitter nitric oxide. We also ascertained that a greater number of genes have diverged in expression by geography than by sex. Moreover, we found that more genes have diverged within females as compared to males between populations. Conversely, we observed no difference in the number of differentially-expressed genes within the ancestral compared to the reinforced population between the sexes. Conclusions This work is consistent with the idea that divergent selection on mating behaviors via cascade reinforcement contributed to evolution of gene expression in P. feriarum . Although our study design does not allow us to fully rule out the influence of environment and demography, the fact that more genes diverged in females than males points to a role for cascade reinforcement. Our discoveries of divergent candidate genes and gene networks related to neurotransmission support the idea that neural mechanisms of acoustic mating behaviors have diverged between populations, and agree with previous neurophysiological studies in frogs. Increasing support for this hypothesis, however, will require additional experiments under common garden conditions. Our work points to the importance of future replicated and tissue-specific studies to elucidate the relative contribution of gene expression divergence to the evolution of reproductive isolation during incipient speciation.

Among several types of parental care behavior, incubation behavior in passerine birds offers an ideal opportunity to study the link between female parental care and male ornamentation, because males generally lack an incubation patch, and thus rarely incubate. Although preceding studies have focused mainly on on-bout duration (or its total amount, i.e., nest attentiveness), it has recently been established that off-bout durations, independent of on-bout durations, are also important for embryo development and thus for efficient incubation. Using Barn Swallows Hirundo rustica, we found that the duration of female incubation off-bouts increased with a sexually selected trait, male throat coloration, independent of female nest attentiveness. A longer female off-bout was positively correlated with the incubation period, indicating that colorful males had reproductive disadvantage because of their mates’ inefficient incubation. Together with a previous study in which females demonstrated a higher amount of incubation when their mates had large white tail spots, another sexually selected trait, our findings indicated that the different aspects of parental care are differently related to male ornaments. Multiple aspects of parental care should be considered when examining the reproductive (dis)advantage of male ornamentation during parental care.

The variation in temperament among animals has consequences for evolution and ecology. One of the primary effects of consistent behavioral differences is on reproduction. In chelonians some authors have focused on the study of temperament using different methods. In our research our first aim was i) establish a methodology to determine the degree of boldness among individuals Rhinoclemmys areolata . Our second aim was to ii) determine the role boldness plays during reproduction, with emphasis on courtship and copulation, considering a) the interactions between males and females, and b) competition between males. We used 16 sexually mature individuals of each sex. Males were observed in four different situations and 17 behavioral traits were recorded. We selected 12 traits that allowed us distinguish between the bolder and the shier individuals and found that five behavioral traits were specific for bolder individuals and five others for shier individuals. In a second step, we observed a male in presence of a female and recorded courtship behaviors and breeding attempts. Bolder individuals did not display courtship behaviors and just attempted to copulate. Shier individuals displayed courtship behaviors and copulation attempts were rarely observed. Finally, in the simulations that compared two males in the presence of a female we noticed that bolder individuals displayed courtship behaviors while the shier ones simply ignored the female. Our results first allowed us to determine which methodology is the best to determine temperament in turtles. Secondly, temperament seems to be an important factor in modulating interaction between males and females. Bolder individuals have an advantage during competition and display courtship behaviours only if other males are present. Shier males displayed courtship behaviors and only try to copulate when no competitors were present. These two different temperament-dependant strategies are discussed in terms of ecology, evolution and management.