Women, behavior, and evolution: Understanding the debate between feminist evolutionists and evolutionary psychologists

The Cost of Mating

The fiddler crab, Uca beebei, lives in individually defended burrows, in mixed-sex colonies on intertidal mud flats. Avian predation is common, especially of crabs unable to escape into burrows. Mating pairs form in two ways. Females either mate on the surface at their burrow entrance ('surface mating') or leave their own burrow and sequentially enter and leave ('sample') courting males' burrows, before staying in one to mate underground ('burrow mating'). We tested whether perceived predation risk affects the relative frequency of these mating modes. We first observed mating under natural levels of predation during one biweekly, semi-lunar cycle. We then experimentally increased the perceived predation risk by attracting grackles (Quiscalus mexicanus) to each half of the study site in two successive biweekly cycles. In each experimental cycle, crabs were significantly less likely to mate on the side with more birds. Moreover, on the side with elevated predation risk, the number of females leaving burrows to sample was greatly reduced relative to the number of females that surface-mated. Males waved less and built fewer mud pillars, which attract females, when birds were present. We discuss several plausible proximate explanations for these results and the effect of changes in predation regime on sexual selection.

L'etude menee aupres des enfants d'un village rural sur la cote orientale de Dominique montre la relation entre le stress et la composition du groupe domestique (âge, sexe, relation intergenerationnelle, nombre de personnes). Les enfants vivant dans des foyers ou prendre soin d'eux est une attitude frequente et stable ont un niveau de cortisol modere contrairement aux enfants connaissant des evenements familiaux traumatiques

The role of oxytocin in male and female reproductive behavior

Reproduction is costly and individual decisions about when and how much to invest in reproduction will relate to potential benefits in terms of offspring survivorship or mating success. For those organisms that can reproduce more than once, individuals should invest relatively more in reproduction when the potential benefits are high. If females gain directly or indirectly from choosing attractive, highly ornamented males, then it could be predicted that females mated to these males should invest more in reproduction. Here we report the first test of this prediction for a lekking species, peafowl (Pavo cristatus), in which males do not provide resources for offspring, and females prefer to mate with those males that possess the most elaborate trains. We find that peahens randomly mated to males that vary in the degree of ornament produce more eggs for those peacocks with more elaborate trains. We could find no evidence to support the possibility that this difference arises as a result of difference between males in their ability to fertilize eggs.

The Special Issue on feminism and evolutionary psychology published by Sex Roles (Smith and Konik 2011) has elicited responses that advance understanding of the debate between evolutionary psychology and feminist perspectives concerning the origins of similarities and differences in the behavior of women and men (Smith and Konik 2013). The further challenges to evolutionary psychology mounted in these responses suggest that the Special Issue has intensified the debate more that it has resolved it. Moving forward requires that feminist psychologists not only add to the considerable body of empirical evidence that challenges evolutionary psychology but also produce alternative evolutionary theories that transcend the nature-nurture controversy that underlies the current debate. To this end, we refer readers to our biosocial constructionist theory in which culture and biology are intertwined in both distal evolutionary processes that shaped human psychology and proximal mechanisms that underlie differences and similarities in male and female behavior (Wood and Eagly 2012).

The relationship between genetic risk for body mass index (BMI) and weight control behaviors remains unknown. The objectives of this study were to determine the association between genetic risk for BMI and weight control behaviors in young adults, and to examine actual measured BMI as a potential mediator variable. We analyzed data from three data collection waves of the National Longitudinal Study of Adolescent to Adult Health. The BMI polygenic score (PGS) was based on published genome-wide association studies for BMI. BMI was collected at 11-18 years and 18-26 years. Weight control behaviors included self-reported: (a) weight loss behaviors (dieting, vomiting, fasting/skipping meals, diet pills, laxatives, or diuretic use to lose weight) and (b) weight gain behaviors (eating more or different foods than normal, taking supplements to gain weight). Among 4,397 participants, the BMI PGS was associated with higher odds of weight loss behaviors in females (OR 1.24, 95% CI 1.14-1.35) and males (OR 1.43, 95% CI 1.26-1.62), and this association was mediated by BMI (indirect effect 0.04, 95% CI 0.03-0.05 in females and 0.03, 95% CI 0.03-0.04 in males). The BMI PGS was associated with lower odds of weight gain behaviors in females and males, which was also mediated by actual BMI. The BMI PGS was associated with weight loss behaviors in both males and females, and this association was mediated by actual measured BMI. Clinical interventions to prevent high BMI, particularly for individuals with genetic risk, may also prevent subsequent development of potentially unhealthy weight loss behaviors.

Most recent models of the partitioning of reproduction attempt to explain patterns of skew on the assumption that dominant individuals have complete control over breeding opportunities within the group, but may nevertheless concede a share of direct reproduction to subordinates as an incentive to remain peacefully in the association. Although these models may be applicable to some animal societies, we argue that they fail to provide a comprehensive theory of skew. Instead, we suggest that subordinates may often be able to claim unsanctioned reproduction for themselves, but will be forced to exercise a degree of reproductive restraint lest they incite ejection by the dominant. Reproductive skew, in other words, may reflect the threat of ejection (inducing subordinate restraint) rather than the threat of subordinate departure (inducing reproductive concessions by dominants). We present a simple ESS model of reproductive skew under these circumstances, which demonstrates that a shift in emphasis from reproductive concessions by dominants to reproductive restraint on the part of subordinates, radically alters the predictions of skew models. High group productivity, high relatedness and (when group members are related) strong ecological constraints are all expected to lead to reduced skew (the opposite conclusions to those of previous, concession-based analyses). The reason is that these factors reduce the benefits (or increase the costs) of ejection to the dominant, who therefore does best to tolerate more subordinate reproduction.

The study of alternative reproductive behaviors in fishes has contributed to our general understanding of reproductive strategies and mating systems. Despite extensive research on the mechanisms and patterns of alternatives, two important factors have not been addressed, and both may strongly influence the evolution of alternative reproductive behaviors. First, alternative female reproductive behaviors exist and should be considered in theoretical and empirical work. Second, interactions between the sexes will influence the evolution of alternative reproductive behaviors. In this review, we explore these two points and suggest the development of a more comprehensive theory of alternatives that will increase our ability to make predictions regarding the existence and expression of alternative reproductive behaviors in both sexes.

BackgroundLimited information exists on the active role of females during mate searching. Theory primarily focuses on male reproductive behaviours, suggesting male distribution follows that of females, while female distribution is influenced by food resources and habitat. This approach might underestimate the females’ role in shaping mating strategies. Incorporating a female perspective into mating studies can enhance our understanding of evolutionary factors.MethodsUsing GPS data from brown bears Ursus arctos across Finland, Romania and Slovakia, we explored female movement behaviour during the mating period. First, we estimated movement speed, total distance and net distance at a daily scale. Then, we quantitatively described when the movement peaks occur by estimating two critical points of the functions described by each of the aforementioned movement parameters: (1) the point in time when the rate of change in brown bear movement behaviour is the highest; and (2) the point in time when each aspect of brown bear movement is most pronounced. We quantified temporal variations in male and female movements throughout the year using generalized additive mixed models, while we used linear mixed models to assess the relationship between peak movement parameters, bear sex and population.ResultsOur findings identified two overlooked behaviours: (1) male and female movement parameters showed the highest rate of change during the mating season, challenging the notion of male roaming as the primary mating strategy; and (2) females travelled the longest distances during the mating season, potentially seeking high-quality mates. This behaviour aligns with the strategy of engaging in copulations with multiple males to avoid infanticide.ConclusionsOur study reveals novel insights into the active role of female brown bears in mating strategies, challenging traditional male-centric views. These results support the need for detailed investigations into female behaviours across mammalian taxa, which offer potential to advance our understanding of mammalian social and mating systems. Local differences also underscore the importance of social and ecological conditions to explain variation in the female role in mating strategies.

On trial again: sociobiology et al.

Male–male competition and female mate choice act contemporaneously in the cockroach Nauphoeta cinerea and the social pheromone of males influences the outcome of both forms of sexual selection. We therefore examined the joint and separate effects of male–male competition and female mate choice to determine if the selective optima for the pheromone were the same or different. Dominant males in a newly established hierarchy mated more frequently, but not exclusively. Manipulations of the multi-component social pheromone produced by males of N. cinerea showed that both long- and close-range attraction of females by males were influenced by the quantity and composition of the pheromone. The most attractive composition, however, differed from that which was most likely to confer high status to males. Since the outcome of male–male competition can conflict with mating preferences exhibited by females, there is balancing sexual selection on the social pheromone of N. cinerea. Such balancing selection might act to maintain genetic variation in sexually selected traits. We suggest that the different forms of sexual selection conflict in N. cinerea because females prefer a blend different to that which is most effective in male–male competition in order to avoid mating with overly aggressive males.

An individual's sexual drive is influenced by genotype, experience and environmental conditions. How these factors interact to modulate sexual behaviors remains poorly understood. In Drosophila melanogaster, environmental cues, such as food availability, affect mating activity offering a tractable system to investigate the mechanisms modulating sexual behavior. In D. melanogaster, environmental cues are often sensed via the chemosensory gustatory and olfactory systems. Here, we present a method to test the effect of environmental chemical cues on mating behavior. The assay consists of a small mating arena containing food medium and a mating couple. The mating frequency for each couple is continuously monitored for 24 h. Here we present the applicability of this assay to test environmental compounds from an external source through a pressurized air system as well as manipulation of the environmental components directly in the mating arena. The use of a pressurized air system is especially useful to test the effect of very volatile compounds, while manipulating components directly in the mating arena can be of value to ascertain a compound's presence. This assay can be adapted to answer questions about the influence of genetic and environmental cues on mating behavior and fecundity as well as other male and female reproductive behaviors.

Studies of the yellow dungfly in the 1960s provided one of the first quantitative demonstrations of the costs and benefits associated with male and female reproductive behaviour. These studies advanced appreciation of sexual selection as a significant evolutionary mechanism and contributed to the 1970s paradigm shift toward individual selectionist thinking. Three behaviours in particular led to the realization that sexual selection can continue during and after mating: (i) female receptivity to remating, (ii) sperm displacement and (iii) post-copulatory mate guarding. These behaviours either generate, or are adaptations to sperm competition, cryptic female choice and sexual conflict. Here we review this body of work, and its contribution to the development of post-copulatory sexual selection theory. This article is part of the theme issue 'Fifty years of sperm competition'.

Molecular cloning of a cDNA encoding a potential water-borne pheromonal attractant released during Aplysia egg laying