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Biologists have long been fascinated by the elaborate courtship displays performed by diverse organisms throughout the animal kingdom. The evolution of courtship behaviour often requires specializations of neural, sensory and motor systems. In addition, physically impressive displays may also require optimized metabolic, respiratory and cardiovascular systems to sustain the neuromuscular demands. Hormonal signalling can reach all of these tissues simultaneously to prepare them for use in courtship. Studies of male golden-collared manakins, Manacus vitellinus, a small bird of the Neotropics with a physically intense and noisy courtship display, have uncovered numerous androgen-dependent neuromuscular and metabolic specializations that enable not only the performance of elaborate courtship routines, but also their evolutionary exaggeration. However, physiological specializations for one function can create limits on their use for other purposes. Such trade-offs may influence the way courtship develops but may also provide information used by females for mate choice. We review this body of work with an eye towards expanding our appreciation of the evolution of widespread tissue hormone sensitivity and hormone action as the system through which elaborate courtship behaviours evolve.

Sexual signal evolution is shaped by whether only one or both sexes execute mate choice. When mate choice by both sexes is considered, the same signalling modality is generally inferred for males and females. In the noctuid moth Chloridea (Heliothis) virescens (Lepidoptera: Noctuidae), both sexes may be signallers and responders, as both emit a sex-specific pheromone. Male mate choice is based on the female sex pheromone, perceived via the antennae, and has been well documented. However, whether females choose partners and whether their choice is based on the male pheromone are unknown. Since female mate choice is expected when males vary in quality, we reared males on two different larval diets that affected their size, which correlated positively with their fitness. When given a choice, more females mated with larger than with smaller males, and these females produced more eggs and larvae. Female choice was not affected by the absolute amount or composition of the male pheromone. Moreover, we found that antennaless females mated as readily as intact females, indicating that antennal sensory input is not required for females to mate. To determine whether females make an active choice, we studied courtship behaviour in detail and observed that females determined the outcome of courtship by moving away from the male (avoidance) or by facilitating copulation with an abdominal bend (acceptance). Additionally, we discovered that tactile sensory stimuli may be involved during courtship. Because tactile interactions may mediate contact-based (chemical) communication, we also investigated putative pheromone components on moth legs, but found no differences between the sexes. Together, our study is the first comprehensive investigation of female mate choice in a heliothine moth.

Reproductive behaviour is often targeted by behavioural parasitism due to its high energy costs and direct relationship with fitness. Courtship behaviour represents a substantial amount of the investment in reproduction, as it usually requires conspicuous movements that are energetically demanding and increase predation risk. Here, we present an alternative reproductive tactic in which dominant male sailfin tetra, Crenuchus spilurus Gunther 1863, parasitize the courtship behaviour of subordinate males. By conducting field observations and controlled experiments in laboratory, we show that, under low availability of nesting sites, dominant males favour a close-range defence of nesting sites, while subordinate males invest more in courtship activities. However, subordinate males often directed courtship movements towards a nesting site dominated by a concealed dominant male, who subsequently took over the female and resumed courtship. Our laboratory experiment also showed that only dominant males obtained spawning success regardless of the amount of effort allocated to courtship behaviour, circumventing the initial female preference for the subordinate male. Subordinate males were more likely to initiate contests and ceased courtship upon losing aggressive contests. In such instances, the courtship effort of dominant males was higher, suggesting that dominant males modulate their courtship effort according to the effort of subordinate males. We refer to this tactic as courtship piracy. For being dependent on resource defence, the effectiveness of courtship piracy is contingent on the defendability of nesting sites. In a follow-up experiment, we show that dominant males invest more in nesting site defence only when nesting sites are scarce. Since rainfall controls the amount of nesting sites in the natural habitat, we suggest that seasonality modulates the relative contribution of courtship piracy and female mate choice to reproductive success.

Across animal taxa, individuals eavesdrop upon courting conspecific males, often in an attempt to steal mating opportunities. While multimodal signals can increase the likelihood that choosers respond to courters, such multimodal signals might also attract the unwanted attention of conspecific eavesdroppers. Previous studies of the brush-legged wolf spider, Schizocosa ocreata, demonstrate that field-experienced males court in response to visual displays of conspecific male courtship more than do laboratory-raised males. Furthermore, other studies demonstrate that males can learn to associate visual signals with the presence of a nearby female. Male S. ocreata, however, use a combination of vibratory and visual signals in their multimodal courtship display. Whether such associative learning varies based on which signal modality is experienced or whether multimodal signals result in enhanced learning remains unknown. Consequently, we examined eavesdropping on courtship behaviours of S. ocreata, with added emphasis on learning to respond to unimodal versus multimodal playback. We used vibratory and video playback techniques to test whether associative learning results in varied courtship levels when males associate unimodal or multimodal courtship signals with the presence of a nearby female. Results show that male S. ocreata associated courtship playback with the presence of a nearby female (i.e. courted at higher levels), regardless of whether courtship playback was unimodal or multimodal, demonstrating that male S. ocreata are capable of learning in multiple modalities. Multimodal playback, however, did not appear to enhance males’ ability to associate conspecific courtship signals with female cues. Courtship behaviours were greater in response to vibratory playback, though, suggesting that male S. ocreata weight modalities differently than females do. We further discuss the implications of this result regarding the communication network of S. ocreata.

Reproductive behaviour is generally under strong natural and sexual selection, meaning that variation in mate attraction investment reveals important fitness trade-offs. Nevertheless, in many taxa with sex-specific displays, individuals differ considerably in such investment. Male white-ruffed manakins, Corapipo altera (Pipridae), exhibit dramatic variation in display investment, despite having a mating system shaped by strong sexual selection. We tested three alternative hypotheses that could explain this variation: (1) individual quality and condition, (2) competition or (3) cooperation. We manipulated the social environment of male manakins at display sites in two experiments. First, we increased the acoustic signalling around focal males’ display sites by broadcasting the sounds of other displaying males to simulate elevated display of neighbouring males. Second, we temporarily prevented neighbouring males from using their display sites, thereby increasing the competition at focal display sites. Males reduced rates of vocalization in response to elevated acoustic signalling, suggesting that males may cooperate with neighbours to advertise the locations of leks, minimizing their individual effort when possible. The number of individuals at the focal display site and the number of silent displays increased when neighbours were prevented from displaying nearby, consistent with the competition hypothesis. However, the constancy in time investment and rates of other display behaviours throughout both manipulations suggests that male quality or condition underlies much of the individual variation in behaviour at display sites. Overall, our results are consistent with cooperation and individual quality mediating individual investment in display site advertisement. While manipulations created opportunities for competition, the responses of focal males were not consistent with antagonist social interactions affecting investment in display. This work demonstrates the importance of both intrinsic and social drivers shaping investment in courtship behaviour and highlights the potential for multimodal displays to facilitate cooperation.

The Northern chamois (Rupicapra rupicapra) is a weakly polygynous species widely distributed in the mountain regions of Europe and the Near East. The Balkan chamois (R. r. balcanica) occurs in the mountain regions of southeastern Europe, and its ecology and behavior during the rut are largely unknown, making it one of the most understudied subspecies of chamois. Despite the scarce body mass dimorphism, males display a developed behavioral polymorphism that affects the mating success and possibly survival. Here, we provide the first quantitative analysis of the behavioral repertoire and activity budget of rutting male Balkan chamois and compare frequencies of different behavioral categories (i.e., courtship and direct and indirect aggression) with those observed in Alpine (R. r. rupicapra) and Tatra (R. r. tatrica) chamois. Male Balkan chamois have a rich behavioral repertoire (24 different behavioral patterns) with a prevalence of courtship behaviors and a higher frequency of indirect than direct forms of aggression. Compared with Alpine and Tatra chamois, no significant difference in the frequency of different behavioral categories was detected. The activity budget showed that when not rutting, males spent ~ 41% of their time foraging and ~ 59% lying down. Time spent rutting was negatively correlated with time spent foraging and time spent lying down, suggesting that time spent for mating activities increased at the expense of foraging and resting. In dominant males, the frequency of courtship behavior was higher than the frequency of aggressive behaviors, whereas in subordinate males, no differences were detected among behavioral patterns. Furthermore, no significant differences in activity budgets were detected between male types. This is the first report of Balkan chamois rutting behavior and provides important insights into the ecology of a poorly known subspecies.

Communication systems often include a variety of components, including those that span modalities, which may facilitate detection and decision-making. For example, female túngara frogs and fringe-lipped bats generally rely on acoustic mating signals to find male túngara frogs in a mating or foraging context, respectively. However, two additional cues (vocal sac inflation and water ripples) can enhance detection and choice behavior. To date, we do not know the natural variation and covariation of these three components. To address this, we made detailed recordings of calling males, including call amplitude, vocal sac volume and water ripple height, in 54 frogs (2430 calls). We found that all three measures correlated, with the strongest association between the vocal sac volume and call amplitude. We also found that multimodal models predicted the mass of calling males better than unimodal models. These results demonstrate how multimodal components of a communication system relate to each other and provide an important foundation for future studies on how receivers integrate and compare complex displays.

Although reproductive behavior is of general interest in evolutionary studies, ecology, and conservation of biodiversity, there are relatively few records on courtship behavior for several animal groups, which include birds, one of the most well-studied vertebrates. Herein we report novel information on a poorly known Neotropical owl species, by reporting courtship displays of the Black-banded Owl (Strix huhula), registered in the Brazilian western Amazon. We describe two events of courtship exhibited by a pair of S. huhula, including vocalization patterns, body movements, and courtship feeding, which suggests that this species possess complex social behavior. Our study provides pivotal information to the understanding of the reproductive biology of the Black-banded Owl and others owl species with similar patterns of reproduction and courtship behavior.

For drug resistance patients, removal of a portion of the brain as a cause of epileptic seizures is a surgical remedy. However, before surgery, the detailed analysis of the epilepsy localization area is an essential and logical step. The Electroencephalogram (EEG) signals from these areas are distinct and are referred to as focal, while the EEG signals from other normal areas are known as nonfocal. The visual inspection of multiple channels for detecting the focal EEG signal is time-consuming and prone to human error. To address this challenge, we propose a novel method based on differential operator and Tunable Q-factor wavelet transform (TQWT) to distinguish the focal and nonfocal signals. For this purpose, first, the EEG signal was differenced and then decomposed by TQWT. Second, several entropy-based features were derived from the TQWT subbands. Third, the efficacy of the six binary feature selection algorithms, binary bat algorithm (BBA), binary differential evolution (BDE) algorithm, firefly algorithm (FA), genetic algorithm (GA), grey wolf optimization (GWO), and particle swarm optimization (PSO), was evaluated. In the end, the selected features were fed to several machine learning and neural network classifiers. We observed that the PSO with neural networks provides an effective solution for the application of focal EEG signal detection. The proposed framework resulted in an average classification accuracy of 97.68%, a sensitivity of 97.26%, and a specificity of 98.11% in a tenfold cross-validation strategy, which is higher than the state of the art used in the public Bern-Barcelona EEG database.

Many species of insects have sex-specific and species-specific cuticular lipid profiles that help regulate mate recognition and courtship behaviour. However, in adult butterflies, little is known about cuticular hydrocarbons (CHCs), the main component of the lipid profile, and their function in mating. Here, we investigated whether Papilio polytes males use cuticular lipids and major CHCs in mate discrimination. When males were presented with freshly killed female and male specimens, copulation attempts were more frequent after contact with the females. Upon removal of the cuticular lipid with solvent washes, the ratios of copulation attempts were similar for both male and female specimens. When male or female cuticular lipid extracts of P. polytes or Papilio protenor (a sympatric and related species) were applied to washed female specimens, males displayed less interest in specimens treated with extracts other than that of the conspecific females. Chemical analysis of the extracts revealed that the CHC profiles, especially the C23–C25 range, differed greatly between the sexes of the two species. Of the identified major hydrocarbons, authentic chemicals 7-tricosene (characteristic of P. polytes males) and 9-pentacosene (characteristic of P. protenor females) greatly reduced the ratio of male copulation attempts with the treated female models. Hence, P. polytes males use the CHC profile of their partner for mate discrimination, and particular alkenes probably play important roles in the prevention of interspecific and same-sex courtships.

Behavioural thermoregulation can ameliorate thermal stress but is costly. For species that court in a thermally stressful microhabitat, sexual selection via endurance rivalry favours individuals that are able and willing to endure harsh conditions in the courtship habitat, as retreats to a thermal refuge will reduce mating opportunities. The relative costs and benefits of refuge use versus continued courtship in the face of thermal risk, which vary across abiotic and biotic contexts, determine the optimal behavioural strategy. We examined the social and abiotic factors driving behavioural decisions related to thermoregulatory retreat in the fiddler crab Austruca mjoebergi. Male fiddler crabs perform a courtship display on the thermally stressful intertidal sediment surface. Time on the surface, and thus time available for display, was limited by high temperatures; as temperature increased, surface time decreased. Yet when presented with a stimulus female, males were more likely to perform the courtship display, displayed at a higher rate and increased time spent on the surface. These results demonstrate that behavioural decisions related to thermal retreat depend both on the abiotic conditions that influence the degree of thermal stress and on the social conditions that influence the reproductive prospects of the individual.

Within populations, individual males adopt different courtship tactics due to differences in their competitive ability, which may vary depending on the animal’s age and size. To test the hypothesis that mule deer (Odocoileus hemionus) and white-tailed deer (O. virginianus) males vary their courtship behavior based on their size, we conducted focal observations of 144 mule deer and 85 white-tailed males that varied in size, at a large grassland site in southern Alberta. The smallest mule deer males devoted more time to feeding, were less likely to engage in late-stage courtship than larger males and were less likely to move among female groups. Other males, including small white-tailed males, appeared to use a roving strategy to search for estrous females in different groups, which is consistent with recent research on male movements. Both medium and large males increased the time they spent in one-male groups, and specifically isolated pairs, as courtship advanced, presumably to reduce competition with other males. However, this trend was most pronounced for medium mule deer males, and for all size classes of white-tailed deer. In contrast, large mule deer males spent a similar proportion of time tending females in all group types. Our results identified potential size-dependent tactics for mule deer males. In contrast, white-tailed males of all sizes appeared to rely on a tactic of finding and tending estrous females in isolation from other males.

Although male courtship displays have evolved primarily to sexually attract females, they also generate inadvertent public information that potentially reveals the courter’s relative sexual attractiveness and the perceived quality and sexual receptivity of the female being courted to nearby eavesdropping male competitors, who in turn may use this information to bias their social partner choices. We tested this hypothesis by first presenting individual eavesdropping male guppies (Poecilia reticulata) the opportunity to simultaneously observe two demonstrator males whose courtship behaviour was manipulated experimentally to differ, following which we tested them for their preference to associate socially with either demonstrator males. Test males preferentially associated with the demonstrator male who they had previously observed courting a female over the other (non-courting) demonstrator. This social association preference was not expressed in the absence of a female to court. Our findings highlight the potential for sexual behaviour influencing male-male social associations in nature.

Urbanization rapidly alters the environment, often leading to decreased biodiversity. One abiotic selection pressure uniquely associated with urbanization is the urban heat island (UHI) effect—wherein built structures (e.g. paved surfaces) capture heat during the day, retain it through the dark cycle and result in significantly elevated night-time temperatures. Relatively few studies have asked what effects the UHI might have on the development and behaviour of urban animals, and even fewer have asked this question of urban arthropod pests who rely on external heat sources and can experience explosive urban population growth rates. In particular, behavioural plasticity is often cited as a critical phenotype for organisms to thrive after rapid environmental change such as urbanization. Here, the relationship between elevated urban temperatures and behaviour was examined in the western black widow spider, Latrodectus hesperus. With regard to the UHI, young spiderlings raised at urban, elevated temperatures showed significantly reduced life span, reduced body mass, elevated web building, heightened voracity towards heterospecific prey and sibling cannibalism. In contrast, males studied later in the final prereproductive moults and raised at urban, elevated temperatures showed reduced life span, decreased adult body condition and increased voracity towards prey. We found no effects of temperature on late-stage male web building or courtship behaviour. UHI temperatures simulated in the laboratory present black widow spiders with a myriad of developmental problems, but our data suggest these spiders use temperature-sensitive behavioural plasticity to attempt to accommodate this stressor.

Sexual signals are often elaborate, even spectacular, behaviours. The reproductive rewards for successful display are great, but so are the potential costs. These costs include not only the resources needed to produce a display, but also resources required if the display evokes attack from a rival or predator. To maximize payoff, individuals must monitor both internal and external cues to adjust display effort. We know surprisingly little about how these competing demands are balanced. Leptin, a hormone secreted by adipose tissue, regulates energy allocation to functions as diverse as feeding, sleep, reproduction and immunity. Despite evidence that leptin influences reproductive trade-offs, its role as a putative regulator of courtship display is poorly understood. Here we examine the use of interoceptive and exteroceptive cues to modulate display effort in Alston's singing mouse, Scotinomys teguina. We manipulated individual perception of energy balance through intraperitoneal injection of exogenous leptin, and we manipulated social context through playback of conspecific song. Leptin-injected mice responded with song to playback more frequently and more quickly than saline-injected controls. Although leptin seems to promote increased song effort, we found that leptin also reduced song duration. Song effort increased after leptin injection and playback of conspecific songs. Understanding the mechanisms by which animals respond to internal and external cues broadens our understanding of context-dependent display as well as behavioural plasticity more generally.

Courtship displays have been traditionally considered stereotyped behaviours. Many elaborate courtships are displayed in specific locations or in courts prepared by the displaying individuals. Sudden environmental events may alter the spatial structure of the displaying site, and individuals should be able to cope with such disruptions. In some mating systems, courtship is the only or main trait used in mate choice. This is the case in lek mating systems where male mating success is highly skewed and intense sexual selection may drive the evolution of elaborate courtship. The golden-collared manakin is a lekking species of the Neotropical forests. Males have an elaborate courtship display that includes a series of acrobatic jumps within a court delimited by small saplings. The courtship ends with a jump on one of the saplings, called the mating sapling, which invites the female to copulate. The display of each male follows a consistent routine that males establish at the beginning of the reproductive season. We hypothesized that males possess behavioural flexibility to adapt their courtship behaviour to unpredictable environmental changes. We investigated the effects of a sudden disruption of the court configuration by placing a piece of bark on the mating sapling. Males gradually established a new display sequence with an alternative mating sapling, demonstrating a high level of behavioural flexibility that suggests the involvement of motor learning. When the bark was removed, some males reverted to the original sequence, showing retention of the original display sequence. Our study provides evidence for the involvement of motor learning in the establishment and adjustment of elaborate courtship displays.

Based on the unusual characteristics of the male pedipalp and male genital morphology, a new genus and new species of Gagrellinae harvestmen, Thunbergia gretae n. gen. n. sp. (male and female) from Shaanxi Province, China, is proposed. The tibia and tarsus of the pedipalp form elaborate palpal claws, resembling gaspipe pliers, probably used to grasp the legs or the pedipalps of the female during courtship. There is no comparable modification of the pedipalp in the female. The penis lacks wing or sac-like (saccate) elements normally present in Gagrellinae, and the penis base is markedly inflated to form a bulb-like structure harbouring the penis muscle. Two or three opisthosomal tergites are fused to the opisthosomal scute and, in combination, cause the male and female bodies to appear elongated and slender. Three further species belong to Thunbergia n. gen., namely Thunbergia grandis (Roewer 1912), Thunbergia wangi (Zhu & Song 1999) and Thunbergia zhui (Zhang & Zhang 2013). The genus Melanopa Thorell, 1889, to which the new species T. gretae n. sp. superficially seems to belong, is re-defined by revision of the type species from Burma (now Myanmar). With respect to courtship behaviour morphological interdependence of penial and of pedipalpal structures within Gagrellinae and Leiobuninae are addressed.

The Western Ghats have a high level of anuran endemism. Although there has been an extensive focus on their taxonomy, the ecology of most species are poorly known. In this note we describe the reproductive life-history traits and breeding behavior of four species of endemic bush frogs, Pseudophilautus wynaadensis, Raorchestes akroparallagi, Raorchestes glandulosus, and Raorchestes ponmudi (Amphibia: Anura: Rachophoridae) from Wayanad region of Western Ghats.

The handicap hypothesis predicts that more elaborate males attract more predators, but are also better able to escape attacks. Thus, a unit increase in trait elaboration has a lower cost for a high-quality male (i.e., differential cost). Although widely accepted, the handicap hypothesis has seldom been appropriately tested, especially concerning the differential cost assumption. Here, we tested this assumption using the jumping spider Hasarius adansoni. The courtship display of male H. adansoni involves bright white patches that contrast with their dark-coloured body. In experimental trials, we measured male escape capacity following a simulated predatory attack. Measurements of escape capacity were correlated to the size of white patches. Contrary to expectations, spiders with larger white patches did not exhibit better escape capacity. We conclude that this trait does not function as a handicap. It is possible that other sexual selection processes are at work.

The red-sided garter snake exhibits a dissociated reproductive pattern, mating at a time when their gonads are quiescent and circulating sex steroids, initially reported to be low, have been found to be elevated during the breeding season. However, the only cue identified that initiates courtship behavior and mating in the red-sided garter snake is an extended period of low-temperature dormancy (LTD) followed by exposure to warm temperatures. In this study, we examined a possible association between winter dormancy, sex steroid hormone metabolism, and initiation of reproductive behavior in the male red-sided garter snake. Upon emergence from winter dormancy, courtship behavior was assessed using attractive females as stimuli. Animals receiving implants containing 1,4,6-androstatriene-3,17-dione (ATD), an aromatase inhibiter, showed little or no courtship behavior, while animals implanted with ATD + 17β estradiol (E2 ) or blank implants exhibited normal courtship. In addition, neurons in the pathways critical in the control of reproductive behavior were examined using the Golgi method. Examination of brains collected upon emergence revealed animals implanted with ATD had a significantly reduced number of dendritic spines compared to controls and animals treated with ATD + E2 . This study provides the first documentation that courtship behavior and mating in the male red-sided garter snake appears to be controlled not by LTD alone, but in conjunction with sex steroid hormones. Moreover, behavioral data suggest that the aromatization of androgens during LTD appears to be critical for the initiation of reproductive behavior in the male red-sided garter snakes.

International audience; Reproductive success can improve with experience, which increases with age in many long-lived species. Signals that provide reliable information about age are therefore of importance for mate choice and consequently are under sexual selection. In birds, these are often vocal signals as well as visual signals in the form of plumage coloration. King penguins, Aptenodytes patagonicus, are sexually monomorphically ornamented seabirds that perform a complex visual and acoustic courtship display. Coloured beak spots and ear patches contain information about the condition and physiological status of adult males and females, but their role as a signal of age has previously only been studied in young birds. Vocalizations have mainly been studied as signals of individuality and not in the context of courtship. We investigated two multicomponent signals in the context of mate choice by analysing beak spot, ear patch and call parameters of wild king penguins. We explored the relation between these signals and age as well as age classes (chicks, juveniles, adults). Ornament parameters were weakly correlated with in males, but not in females, while acoustic parameters were highly correlated with age in both sexes. The calls' fundamental frequency and energy parameters and all the beak spot parameters reliably classified individuals into their age class. Since age class was redundantly encoded in both acoustic and colour parameters, we hypothesize that calls and ornaments function as back-up signals that increase the chance of accurately conveying the age class of the sender to receivers. King penguins might sequentially analyse age class signals during courtship, where acoustic signals serve as long-range communication when sender and receiver are out of sight, and ornamentation signals become important at close range. We show the importance of considering bimodal, multicomponent signals when studying complex behaviour and discuss how signalling environment, the species' life history and mating system influence the evolution of communication signals.

Recognizing conspecific individuals from other members of the community is important for many interactive behaviors, especially those involved in mate selection. We investigated whether male courtship behavior is triggered by chemical cues left by females on the substrate using the sedentary litter-dwelling scorpion Tityus pusillus Pocock, 1893, which is a small and common species distributed throughout the northeast Atlantic Forest in Brazil. In experiments using 50 pairs, we tested whether males recognize females by detecting sex-specific chemicals on the substrate. All males changed their behavior, performing pre-courtship acts when exposed to female-specific chemicals on the substrate, but they did not change their behavior when exposed to a clean substrate lacking female-specific chemicals. These results show that the male T. pusillus alters its behavior in the presence of female chemical cues, suggesting that males recognize females by detecting compounds left on the substrate and that the presence of these chemicals trigger the courtship behavior of the male T. pusillus.

Alar (Daminozide), a plant growth retardant, is used in different fruit orchards especially of apples and mangoes to increase the production by preventing pre harvest fruit drop, promoting colour development and increasing the storage life. In an earlier study we have demonstrated both neurotoxic and teratogenic effects of Alar in a model organism Drosophila melanogaster. As an extension of the previous work, the present study is designed to investigate the effects of Alar on larval and adult behaviour of the fly. The Results demonstrated no significant alteration in feeding rate of treated larvae, but their foraging path length was shortened considerably, indicating impaired locomotion. Moreover, the onset of their specific courtship behavior like orientation, tapping and wing vibration was significantly delayed which suggest that the treated males were less vigorous and females were less receptive than the controls. In addition, Alar treatment was associated with reduction in copulation duration and subsequent decline in Courtship Index indicating lower reproductive fitness. Collectively, the findings suggest that Alar is ethotoxic for D. melanogaster.

Understanding patterns of diversity in sexual signals can give insight into processes initiating, mediating or following from species diversification. Here we focus on female sex pheromones, which are widespread among animals, where some taxa show phylogenetic patterns of variation, but for others, ecological factors better explain pheromone diversity. Causes of differences in these patterns are unclear, and general insights require studying a broader range of taxa. Here we examined variation in the responses of male redback spiders, Latrodectus hasselti, to sex pheromones produced by three allopatric female congeners with different degrees of phylogenetic relatedness (from the same clade: Latrodectus mirabilis, Latrodectus hesperus; and from a different clade: Latrodectus geometricus) to infer pheromone divergence. We examined variation in male responses to conspecific and heterospecific females’ airborne and contact pheromones, which attract males and elicit courtship behaviour, respectively. We measured male courtship responses to extracted contact pheromones in isolation and male preferences in response to airborne pheromones and combined cues (pheromones, silk) in a two-choice maze. Male responses to airborne chemicals, contact chemicals and combined cues suggested variation in species specificity, with L. hasselti males showing strong discrimination against airborne pheromones of L. hesperus females (same clade), moderate evidence for discrimination based on contact cues of L. geometricus, but only when multiple sources of information were available (different clade), and no discrimination of L. mirabilis females (same clade) relative to conspecifics, regardless of the types of information available. Thus, male responses were not consistent with a phylogenetic pattern. Moreover, airborne pheromones can apparently diverge relatively rapidly, but airborne and contact pheromones may remain similar across long evolutionary timescales. We propose that differential responses to L. hesperus may arise from selection for population-level pheromone divergence within that species and that, in general, pheromones and male responses may be evolutionarily conserved across Latrodectus.

To better understand the social monogamy in decapod crustaceans, individual recognition in a socially monogamous shrimp, Lysmata debelius, was investigated. We hypothesized that chemical cues play an important role in mediating monogamy, because chemical cues is the primary form of communicaition. To test this, we first examined mate recognition and second tested the presence of chemical cues in individual recognition. The individual recognition to conspecifics of different reproductive statuses was tested in a Y-maze excluding visual cues and tactile cues. Inter-molt and pre-molt euhermaphrodite-phase shrimps served as males and females, respectively. A focal male (cue detector) was placed in the bottom chamber, and two shrimps (cue releasers) of different statuses were placed in the upper two champers, respectively. We find that the focal male spent more time in the front of the chamber holding the paired partner when the other shrimp was not female, and prefered to the female stranger rather than its male partner. Interestingly, when both stranger and partner were females, the focal male actually spent more time in the chamber holding the female stranger. The results indicate that olfactory chemical cues mediate monogamy in L. debelius in place of visual cues, and the chemical cues are probably individual specific (i.e. identification odor). The courtship and mating behaviors of L. debelius were also reported for the first time. During mating, L. debelius displayed no courtship behavior, differing from its sister species, L. wurdemanni which live in aggregation, and L. amboinensis which live in low denstiy. Combining the previous results in L. wurdemanni and L. amboinensis, we can conclude that L. wurdemanni has the most elaborate precopulatory courtship rituals, L. amboinesis has less, and L. debelius has none, i.e. the behavioral activity between male and pre- and post-molt female decreases with the population intensity. This behavioral pattern should be sexually selected in different social systems. The present study would enrich our understanding of the evolution of social-dependent behaviors in crustaceans.

While the mate choice literature has focused primarily on the choices that females make, under certain circumstances males are expected to make mating decisions as well. Such circumstances include when males provide a significant energetic investment in a female or her offspring. Male orthopterans can invest considerable resources in females and have been studied for their mating investment decisions. However, while males provide acoustic information to females, females do not provide reciprocal acoustic information to males. Here, we tested the hypothesis that Laupala males use chemical signals to make mating decisions. We found that males and females have discernable differences in cuticular lipid expression when considering both whole-body and antennae-only extracts. Furthermore, access to the antennae alone resulted in males showing more courtship towards females and more aggressive behaviours towards males. Finally, males showed higher levels of association and courtship behaviour near female-exposed filter paper than they did near male-exposed and control filter paper. These results suggest that Laupala males use chemical signals when deciding whether to initiate courtship and open the possibility that chemical communication has played a role in the diversification of this genus.

Songbirds hold a prominent role in the fields of neurobiology, evolution, and social behavior. Many of these fields have assumed that females lacked the ability to produce song and have therefore treated song as a male-specific behavior. Consequently, much of our understanding regarding the evolution and neural control of song behavior has been driven by these assumptions. Here we review literature from diverse fields to provide a broader perspective of the role of females in vocal communication and courtship. Recent evidence indicates that song evolved in both males and females and instances of female song are still common. The specialized neural circuit known as the "song system," which is necessary for singing in males, is also present in females, including those that do not sing, implying broader functions that include evaluating male song and controlling courtship behavior. In addition to having flexible, individualized preferences, females actively shape their social network through their interactions with males, females, and juveniles. We suggest that by developing more accurate hypotheses concerning the role of females we may better understand the evolution and neural mechanisms of song production and courtship behavior.

This work was supported by Portuguese National Funds through FCT (Fundação para a Ciência e a Tecnologia), within the cE3c Unit FCT funding (grant number UID/BIA/00329/2013), IO PhD grant (SFRH/BD/90686/2012) and SAMV (SFRH/BPD/66042/2009 and PTDC/BIA‐ANM/0810/14) and MB (SFRH/BPD/82259/2011) Post‐Doctoral research grants. This work was also supported by the ERC (European Research Council) AdG BioTIME (250189) to AEM. Sexual selection theory suggests that males need to constantly reappraise their mating decisions to take account of the presence and the phenotypes of their rivals. Here we examine this expectation by asking: (i) If the presence of a rival influences male mating behaviour; (ii) How important is the attractiveness of the rival (absolute attractiveness) in shaping male behaviour; and (iii) How does a male's attractiveness in comparison to his rival (relative attractiveness) influence a male's mating decisions. Using the Trinidadian guppy, a species in which female mate choice (based on males’ attractive traits) plays an important role in male mating outcomes, we recorded the frequency of courtship displays and unsolicited attempts by focal males. First, we quantified focal male mating behaviour with and without a rival. Since the probability of a successful mating is, on average, halved by the presence of a rival, we predicted that under competition the focal male would invest more in less costly mating tactic—unsolicited attempts. Second, we examined how the rival's standard length and area of orange coloration mediated focal male mating behaviour. We found that rival presence influenced how focal males responded to females in terms of both mating tactics. However, the rival attractiveness elicited changes only in male courtship display. Focal males increased courtship display rate if his rival was small or if possessed large amounts of orange, regardless of considering rival absolute or relative attractiveness. Our results show that males invest in the costlier mating tactic when there is no rival or in the presence of a smaller rival. Interestingly, they make a similar investment in the presence of an attractive orange rival. Overall, this study highlights the importance of fine‐grained male decisions in mating encounters and shows that mating tactics are differentially shaped by multiple competition risk cues. Postprint

Many metabolic consequences of the excess lipid storage observed in obesity have been documented in humans and mammals, but the effects of an obese phenotype on reproductive behavior are less understood. Drosophila melanogaster (Meigan, 1830) is well suited to study the ramifications of excess energy storage as they are commonly used to explore the genes important for energy utilization. However, little is known about the reproductive behavior of mutants in these metabolic genes. Therefore, we tested, for the first time, courtship of the naturally occurring adipose (adp60) mutation which accumulates excess triglycerides and glycogen. Adipose mutants showed decreased courtship behaviors as well as copulation rate. The decrease in copulation rate could in part be explained by the decrease in courtship behaviors such as wing scissoring and wing vibration. Taken together, the data presented here suggest that the adp60 mutants may negatively affect male fly reproductive behavior and provide a system to further our understanding of the genetic and metabolic control of reproductive behaviors and reproductive potential.

In outcrossing hermaphrodites with unilateral mating, where for each mating interaction one individual assumes the female role and the other the male role, each individual must take a sexual role opposite to that of its partner. In the polychaete wormOphryotrocha diadema, the decision on sexual role is likely at stake during the day-long courtship. Here we describe, for the first time, courtship and pseudocopulation in this species, quantify their pre-copulatory behavior, and search for behavioral traits predicting the prospective sexual role (i.e., behavioral sexual dimorphism), by analyzing the courtship behavior of pairs of worms during the day preceding a mating event. We did not find any behavioral cue predicting the sexual role worms were to play; partners’ pre-copulatory behaviors were qualitatively and quantitatively symmetrical. We interpret this as the outcome of a war of attrition where partners share the preference for the same sexual role, and both hide their ‘willingness’ to play the less preferred one, until one individual reaches its cost threshold and accepts the less preferred sexual role.

Synopsis Gonadal hormones can activate performance of reproductive behavior in adult animals, but also organize sex-specific neural circuits developmentally. Few studies have examined the hormonal basis of sex differences in the performance of elaborate, physically complex, and energetic male courtship displays. Here we describe our studies over more than 20 years examining sex difference and hormonal control of courtship in Golden-collared manakins (Manacus vitellinus) of Panamanian rainforests. Our recent studies of birds studied in an artificial “lek” in a rainforest aviary provide many new insights. Wild and captive males and females differ markedly in their performance of male-typical behaviors. Testosterone (T) treatment augments performance of virtually all of these behaviors in juvenile males with low levels of circulating T. By contrast, T-treatment of females (with low circulating T) either failed to activate some behaviors or activated male behaviors weakly or strongly. These results are discussed within a framework of our appreciation for hormonal versus genetic basis for sex differences in behavior with speculation about the neural mechanisms producing these patterns of hormonal activation.

Courtship behavior was observed for 14 butterfly species, including seven species belonging to tribe Theclini, Lycaenidae, to address whether males of sexually dichromatic species perform more active demonstration of their wing surface to the female than those of monochromatic species do. Males in nearly half of the dichromatic species kept their wings closed on the thorax throughout most of a courtship, indicating no general relationship between the mode of wing coloration and courtship behavior. The results obtained are discussed from ecological and phylogenetic points of view, and it is inferred that the wing-closed courtship has developed in the Theclini group as adaptation to predation pressure in the woodland habitat.

Our knowledge about the acoustic behavior of Caviinae species drove us to investigate Kerodon rupestris’s (Caviidae: Hydrochoerinae) repertoire. This species is endemic to Caatinga and states as vulnerable in the Brazilian list of endangered species. We recorded sounds uttered by individuals from Santa Luzia, State of Paraiba, Brazil. We promoted interactions among 13 animals during intra and intersexual pairing sessions, under undisturbed interactions in captivity, and in free-living conditions. We found a repertoire of 13 call types, most of them (all except three) shared with Cavia and only five possibly shared also with Hydrochoerus: (1) Close contact and cohesion: tonal and noisy contact calls, tweet, slow-whistle; (2) Social regulation (incitement, subordination or auto-defense): whine, peepy-squeak, yelp; (3) Offensive aggression and status display: roar, snort, and teeth-chattering (4) Warning or intimidation: alarm-whistle, drrr, and drumming; (5) Courtship: purr and slow-whistle. The similarity of Kerodon signals to Hydrochoerinae species, despite the ecological differences, needs to be understood in comparative phylogenetic studies tracing back the origin of the courtship display in Caviidae. Thus, future research should focus on playback studies to test signals' biological function hypothesis.

Because intrauterine environment differs between twins and singletons, twin-born lambs are often studied when effects of fetal programming are evaluated. In sheep, fetal programming might have effects on reproductive physiology and behavior after sexual maturation. The aim of this study was to compare sperm output and sexual behavior in developing singleton- or twin-born lambs of similar body weight. Singleton lambs (n = 12) and twin (n = 9) male-male lambs were used. From 5.4 until 9.1 months of age, body weight, scrotal circumference (every 3-4 weeks), sexual behavior (every 14 days) and semen characteristics (every 28 days) were evaluated. In the third ejaculate, singleton lambs ejaculated a larger volume of semen than twins (P = 0.03). Considering a pool of the three ejaculates, twin lambs ejaculated semen with a greater sperm concentration than singleton lambs (P = 0.015). There was an interaction between group and time to the onset of courtship behavior (P = 0.02) and a tendency for an interaction in the number of mount attempts (P = 0.052). Singleton-born lambs, during the first evaluation period began courtship behavior earlier than twin-born lambs (P0.0001). In conclusion, there were only slight differences in semen and sexual behavior between male ram lambs born as singletons or twins with similar weight. Male ram lambs born as singletons initiated the courtship behavior earlier than twins during the first sexual behavioral evaluation period, ejaculated a larger volume of semen in the third consecutive ejaculate, and there was a lesser sperm concentration in the three ejaculates.

Many animal species show aggression to gain mating partners and to protect territories and other resources from competitors. Both male and female fruit flies of the species Drosophila melanogaster exhibit aggression in same-sex pairings, but the strategies used are sexually dimorphic. We have begun to explore the biological basis for the differing aggression strategies, and the cues promoting one form of aggression over the other. Here, we describe a line of genetically masculinized females that switch between male and female aggression patterns based on the sexual identity of their opponents. When these masculinized females are paired with more aggressive opponents, they increase the amount of male-like aggression they use, but do not alter the level of female aggression. This suggests that male aggression may be more highly responsive to behavioral cues than female aggression. Although the masculinized females of this line show opponent-dependent changes in aggression and courtship behavior, locomotor activity and sleep are unaffected. Thus, the driver line used may specifically masculinize neurons involved in social behavior. A discussion of possible different roles of male and female aggression in fruit flies is included here. These results can serve as precursors to future experiments aimed at elucidating the circuitry and triggering cues underlying sexually dimorphic aggressive behavior.

Males and females have divergent reproductive interests arising from their unequal investments in offspring. This sexual conflict drives an antagonistic arms race that influences sex-specific reproductive success. Alternative reproductive tactics are expected in long-lived species for which the reproductive strategy that maximizes mating success could differ across body sizes. The mating strategy of the painted turtle (Chrysemys picta) has been characterized as an elaborate and amiable male courtship display during which males use their elongate foreclaws to stroke females, coupled with female mate choice. Contrary to this long-held understanding, in situ field observations and experimental trials from our long-term study in Algonquin Provincial Park, Canada, demonstrate that males also exhibit an alternative, coercive mating strategy. Males are equipped with sexually size dimorphic tomiodonts, tooth-like cusps of the beak, as well as a weaponized anterior shell, with which they wound the head and neck of females. Behavioral trials during the breeding periods showed that male reproductive tactics shift from courtship (foreclaw display) to coercion (striking, biting, and forced submergence) across ontogeny, and male size predicts the occurrence and frequency of coercive behavior. We found phenotype-behavior matching whereby small males invest in putatively ornamental foreclaws used for courtship and large males invest in weaponry for coercion, challenging existing knowledge of this well-studied species. As a group with a long evolutionary history and varied mating systems, Testudines are a particularly interesting taxon in which to ask questions about mating system evolution. Alternative reproductive tactics are hypothesized for long-lived species. We quantified a shift from apparent courtship to coercive tactics during the reproductive lifespan of a well-studied freshwater turtle. Male painted turtles (Chrysemys picta) have sexual weapons that are used to promote female acquiescence. Using behavioral trials with turtles from a long-term study population, we demonstrate that males match their morphology (ornament/weapons) to reproductive behavior (courtship/coercion) as their reproductive tactics shift. Our findings hint at the behavioral complexity of aquatic turtles, a challenging and often-overlooked group in behavioral studies.

Macrostemum Kolenati 1859 is a cosmopolitan caddisfly genus with 105 described species easily recognized by the remarkable contrasting dark and clear wing patterns. The larvae of the genus build retreats with capture nets adapted to filter fine particulate organic matter. The genus has 19 described, Neotropical species, almost all described only by wing patterns and male genitalia. To date, only two Neotropical species have an associated immature stage and only one has the female genitalia described. Macrostemum brasiliense occurs in southeastern Brazil, primarily in the Atlantic Rainforest. The species has characteristic wing and body patterns, and phallic morphology recorded in literature and further described here. We contribute to knowledge of this species by further describing and illustrating the female genitalia, adding detail about wing variation patterns and venation, including the intriguing melanic female variation. This conspicuous Atlantic Rainforest caddisfly is now among the best-known species of Neotropical Trichoptera.

Synopsis Courtship behavior in salamanders is often complex and involves well-documented communication from males to females in multiple sensory modalities. Historically, behaviors exhibited during the major stages of courtship have been predominately framed as a male acting and signaling to “persuade” a passive female to participate in courtship and remain with him until sperm release is completed. In this review, we use courtship descriptions for lungless salamanders (Plethodontidae) as a case study to illustrate this historical bias of a male-centered perspective. We then re-examine the literature and summarize the many ways females are active participants during plethodontid courtships. We also relate female behaviors to the types of female-to-male communication that may occur. For example, females have been documented to approach a male and initiate courtship, participate in mutual head rubbing, and step astride the male’s tail to begin the tail-straddling walk (a key courtship behavior observed in all plethodontids). Additionally, females have glands that may produce chemical signals that males respond to during courtship. We conclude that communication during courtship is more accurately described as a two-way interaction where each partner’s behavior is coordinated with the other’s via multi-modal signaling. Shifting the lens through which we view courtship and behavior provides insight into which female behaviors and anatomical features are most likely to be used for communication with males.

Made available in DSpace on 2020-12-12T02:01:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-06-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Courtship and breeding behaviour of anurans is species-specific and defined by vocalisation, although breeding activities are still understudied for many species. Here, we describe the courtship behaviour and unpublished associated vocalisation (release and aggressive calls) of Rhinella ornata at a degraded area of the Brazilian Atlantic Rainforest within Xixová-Japuí State Park (PEXJ). Fifteen subjects distributed in five subgroups in the same lek-like systems were observed during two consecutive nights in September 2015, totalling eight fieldwork hours. A total of 79 vocalisations were analysed, and the behavioural sequence of activities carried out by the subjects was described. Results show a pattern regarding the behavioural sequence exhibited by males, starting with the arrival of the resident male at the calling site and its vocalisation to an intruder male. Although this sequence did not vary between the five observed groups, a slight difference in the time they started was reported, but with a narrow range. We also provided the first description of the release call for this species. The overall behavioural tactics of R. ornata to approach females seem uncommon among bufonids. Although further investigation is required to better understand additional aspects of the courtship and breeding behaviour of R. ornata, our findings improve the overall understanding of this species’ biology. Laboratório de Paleontologia de Vertebrados e Comportamento Animal (LAPC); Centro de Ciências Naturais e Humanas (CCNH) Universidade Federal do ABC (UFABC) Programa de Pós-graduação em Biodiversidade de Ambientes Costeiros Instituto de Biociências Universidade Estadual Paulista (UNESP), Campus do Litoral Paulista Laboratório de Herpetologia (LHERP) Instituto de Biociências Universidade Estadual Paulista (UNESP), Campus do Litoral Paulista Programa de Pós-graduação em Biodiversidade de Ambientes Costeiros Instituto de Biociências Universidade Estadual Paulista (UNESP), Campus do Litoral Paulista Laboratório de Herpetologia (LHERP) Instituto de Biociências Universidade Estadual Paulista (UNESP), Campus do Litoral Paulista CAPES: 1769051

In theory, a male should change the allocation of fighting and mating efforts in relation to his age. Thus, the consequences of sexual selection may be complicated by changes in the male resource allocation due to aging. However, previous studies have focused on changes in female mate choice and male-male competition with aging separately, and the impact of aging on the relationship between mate choice and male competition is unknown. Here, we examined how male competitiveness and attractiveness and their relationship changes over male lifespan in Gnatocerus cornutus. In this species, males perform courtship displays and fight rival males for mates. Older males are more competitive in male fighting and aggressive toward females than younger males. The aggression is also directed toward females. Almost all older males who attacked a female failed to copulate, while younger males never attacked the females. As a result, copulation success decreased with age. When an older male did not mistake a female for a male, he exhibited more frequent courtship. However, mating with older males imposed direct costs on females in terms of both fecundity and lifespan, with no offsetting indirect benefits for her offspring. The courtship behavior of older males does not supply females with cues for mate-choice benefits but are used to coerce females into mating. Our results suggest that male–male competition constrains female preference for older males. Thus, female choice and male–male competition may not be reinforcing in older G. cornutus males. When males get older, they often pay more attention to females in a variety of ways, such as courting and fighting for access. This is because older males have not long to live. In Gnatocerus cornutus as well, older males attend to fighting and courting. The older males seem to be competitive in male fights and attractive to females. However, they are not only aggressive toward rival males but also sometimes use violence on females. As a result, these older males are rejected by the assaulted females and cannot mate. Additionally, the violence of older males can reduce female fecundity and lifespan. Thus, mating with older males is costly to females in G. cornutus, and a female preference for older males is not expected to evolve.

Performance trade-offs can dramatically alter an organism's evolutionary trajectory by making certain phenotypic outcomes unattainable. Understanding how these trade-offs arise from an animal's design is therefore an important goal of biology. To explore this topic, we study how androgenic hormones, which regulate skeletal muscle function, influence performance trade-offs relevant to different components of complex reproductive behaviour. We conduct this work in golden-collared manakins (Manacus vitellinus), a Neotropical bird in which males court females by rapidly snapping their wings together above their back. Androgens help mediate the snap displays by radically increasing the twitch speed of a dorsal wing muscle [scapulohumeralis caudalis (SH)], which actuates the bird's wing-snap. Through hormone manipulations and in situ muscle recordings, we test how these positive effects on SH speed influence trade-offs with endurance. Indeed, this trait impacts the display by shaping signal length. We find that androgen-dependent increases in SH speed incur a cost to endurance, particularly when this muscle performs at its functional limits. Moreover, when behavioural data are overlaid on our muscle recordings, displaying animals appear to balance display speed with fatigue-induced muscle fusion (physiological tetanus) to generate the fastest possible signal while maintaining an appropriate signal duration. Our results point to androgenic hormone action as a functional trigger of trade-offs in sexual performance—they enhance one element of a courtship display, but in doing so, impede another.

International audience; Avian eggs contain a large number of molecules deposited by the mother that provide the embryo with energy but also potentially influence its development via the effects of maternally-derived hormones and antibodies: the avian egg is “multivariate”. Multivariate effects on offspring phenotype were evaluated in a sister study on captive zebra finches, by simultaneously manipulating maternally derived antibodies after LPS-treatment of mothers and egg-treatment using yolk testosterone injection. LPS-treatment had a positive effect on body mass growth at 30 days after hatching and immune response at sexual maturity, while egg-testosterone positively influenced immune response at fledging and courtship behaviour in sexually mature male offspring. Maternal effects are known to modulate offspring telomere length. Still, the multivariate effects of egg-derived maternal components on offspring telomere dynamics from hatching to sexual maturity are undefined. Here, using the data of the sister study completed with telomere measurements, we tested a) the effects of LPS and T treatments on telomere length (TL) from hatching to sexual maturity (day 82), b) how LPS treatment modulated telomere length over reproduction in adult females, and c) the relationship between maternal and offspring TL. We predicted, a) TL would be shorter in LPS fledglings (as a cost of faster growth), and b) TL would be longer in sexually mature adults from T-treated (as a proxy of individual quality). In adult females, there was an overall negative relationship between laying and rearing investments and telomere length, this relationship being weaker in LPS treated females. In chicks, there was an overall negative effect of LPS treatment on telomere length measured at fledging and sexual maturity (day 25 – 82). In addition, at fledging, there was a sex x LPS x T-treatment interaction, suggesting the existence of antagonistic effects of our treatments. Our data partially support the hypothesis of telomeres are proxies of individual quality and that individual differences in telomere length are set-up very early in life.

The present work aimed at studying the sicklefin devil ray (Mobula tarapacana) that aggregates seasonally in the Saint Peter and Saint Paul Archipelago (SPSPA). From December 2008 to June 2016, 827 rays were sighted through free diving visual census survey. From the total of the records, it was possible to identify the sex of 361 specimens, in which 215 were females and 146 were males. The disk width ranged from 2.40 m to 3.20 m with mean size of 2.60 m, for both males and females, indicating that the population is composed by sub-adults and adults. Using photo-identification of the pectoral-fins in the ventral side, 11 males and 44 females were identified and compared with each other, but no re-sight was detected. Recent mating scars were observed in males (n= 7) and females (n= 6), as well as courtship and pursuit behaviors, confirming that the SPSPA is an important area of aggregation and mating for M. tarapacana in the Atlantic Ocean. Resumo O presente trabalho teve como objetivo conhecer a população da raia manta chilena (Mobula tarapacana) que forma agregações sazonais no Arquipélago de São Pedro e São Paulo (ASPSP). Durante o período de dezembro de 2008 a junho de 2016, foram avistadas 827 raias através de censo visual por mergulho livre. Do total das raias avistadas, foi possível identificar o sexo de 361 espécimes, dos quais 215 eram fêmeas e 146 eram machos. A largura de disco variou de 2,40 m a 3,20 m, com média de 2,60 m, tanto para machos como para fêmeas, evidenciando que a população é composta por adultos e sub-adultos. Com base na foto-identificação do padrão de coloração do contorno localizado na região ventral, foram identificados e comparados entre si, 11 machos e 44 fêmeas, não tendo sido observada, porém, nenhuma reavistagem. Marcas de cópula recente foram observadas tanto em machos (n= 7) como em fêmeas (n= 6). Comportamentos de corte e perseguição também foram observados, indicando que o ASPSP é uma importante área de agregação e acasalamento da espécie no Oceano Atlântico.

Body size, nuptial gift characteristics and courtship behaviour, among other traits, can reflect the quality of a potential mate and, thus, might be under sexual selection. To maximize their mating success, individuals can show behavioural plasticity in sexual context. Allocosa senex is a burrow-digging wolf spider that exhibits reversal courtship roles and in sexual size-dimorphism expected for spiders. Males construct the mating refuge and females prefer males that build longer burrows, which are considered as nuptial gifts because they are delivered to them after mating. This study aims to determine whether male body size and female reproductive status influence burrow dimensions, courtship displays, female preferences and cannibalism rate in A. senex. For that purpose, we allowed males to construct burrows and performed sexual trials under laboratory conditions. Larger males were more courted by females, and in turn, they expressed more vibratory behaviours during courtship. However, and contrary to our expectations, smaller males constructed longer burrows. We suggest that males of A. senex exhibit size-dependent behavioural plasticity, and when they are smaller, they invest more in burrow construction to compensate their lower opportunities of courting intensively as larger males. In addition, females courted differentially according to their reproductive status, overriding male preferences for virgin females. This study opens several doors to future research regarding mutual choice in A. senex and the traits assessed by males and females during courtship, as well as about the influence of intrinsic and extrinsic factors shaping reproductive decision-making in this and other wandering spider species.

Circulating hormone levels often vary considerably among males competing for mates, but how this variation affects the signalling phenotype is poorly understood. In the green treefrog, Hyla cinerea, males competing for mates engage in vocal contests that increase circulating levels of the adrenal glucocorticoid corticosterone (CORT) and decrease androgens in contest losers, who characteristically adopt a noncalling ‘satellite’ mating tactic. We previously showed that CORT administration to calling males reduces vocal effort and increases the probability of satellite behaviour during simulated territorial intrusions, suggesting that elevated CORT compromises vocal quality and decreases the propensity to call in a context-dependent manner. However, the extent to which these effects reflect variation in vocal behaviour of males in natural choruses is unclear. Here, we examined how hormone levels, social context and other potential determinants of vocalization, including body size and condition, relate to vocal attributes and behaviour in calling males and in associated satellites after removal of calling ‘host’ males. Results revealed that satellites had higher CORT and lower androgens and were smaller and in poorer condition than host males. Host removal resulted in vocalization in 74% of satellites. These males invested less effort in vocalization than hosts, and CORT level best explained these differences. The remaining 26% of satellites did not vocalize after host removal and had lower androgens than satellites that vocalized. Results provide support for context-dependent effects (i.e. host presence/absence) of elevated CORT on the probability of vocalization and link high CORT to reduced vocal quality. In contrast, low androgens were associated with a low probability of vocalization regardless of social context, and androgen level was a poor predictor of vocal attributes. Our results link high CORT and low androgens to variation in signalling quality and behaviour that potentially reduces the probability of attracting females.

Stress impacts social relationships. In turn, social relationships buffer the stress response in some species. Studies that have investigated the role of corticosterone (CORT) on courtship, mate choice, mating, and pairing have found mixed results. We therefore tested the role of CORT in these steps of the pairing process in the monogamous zebra finch. Male and female zebra finches received either one of 2 doses of corticosterone (CORT, 10 μg and 20 μg, referred to as low and high dose) or a vehicle control (peanut oil). Subjects were then given the opportunity to pair in mixed sex aviaries. Courtship and pair bonding behaviors were observed over 3 days. Overall, zebra finches of both sexes were equally likely to pair or not pair regardless of treatment, although a high dose of CORT increased the latency to form a pair bond. There were no effects of CORT on courtship behavior in either sex, though the low dose increased undirected (non-courtship) singing in males relative to the high dose. Animals treated with CORT, regardless of dose, engaged in fewer copulations than did control animals. When we examined pairing behaviors, we found a decrease in co-nesting in low dose animals. Our results suggest that acute CORT has few effects on pair bonding, suggesting species-specific effects of CORT on behavior.

Stress in animals can have extensive repercussions on other life history traits. Male Drosophila melanogaster under long-term selection for starvation-resistance (starvation stress) had reduced wing-waving courtship behavior in comparison to control males. However, only control females required longer courtship time from this reduced courtship effort; starvation-selected females mated equally with starvation-selected and control males. This suggests that there are behavioral trade-offs with starvation stress including reduced courtship behavior in males and relaxation of female choosiness.

Sexually selected displays often include suites of integrated traits. Black morph males of the poeciliid fish Girardinus metallicus perform courtship and aggressive displays that exhibit their conspicuous yellow and black coloration. Body size, gonopodium size and ventral black area are correlated with intermale aggression, which is key for access to mates. A previous study showed that females may prefer dominant males prior to watching them fight; however, that result was obtained in trials that allowed for male-male interactions across partitions, and to date no study has uncovered the traits important in female choice. We performed a more comprehensive investigation of the multicomponent sexual display including measures of male yellow hue, saturation and brightness. We examined the behavior of size-matched males paired to maximize the difference in yellow saturation, and measured female choice exclusive of male-male interactions and chemical cues. We found no female preference for any traits in the multicomponent sexual display. Males with brighter and more saturated yellow coloration were more likely to be dominant, and dominant males courted and attempted copulations more. Our results suggest that yellow coloration is sexually selected; however, the courtship display requires further investigation because we did not identify targets of female preference, and we discuss possible explanations for this finding.