Sexual selection is a major force driving the evolution of elaborate male sexual traits. Handicap models of sexual selection predict that male sexual traits should covary positively with condition, making them reliable indicators of male quality. However, most studies have either manipulated condition through varying diet quantity and/or caloric content without knowledge of specific nutrient effects or have correlated proxies of condition with sexual trait expression. We used nutritional geometry to quantify protein and carbohydrate intake by male cockroaches, Nauphoeta cinerea, and related this to sex pheromone expression, attractiveness, and dominance status. We found that carbohydrate, but not protein, intake is related to male sex pheromone expression and attractiveness but not dominance status. Additionally, we related two condition proxies (weight gain and lipid reserves) to protein and carbohydrate acquisition. Weight gain increased with the intake of both nutrients, whereas lipid reserves only increased with carbohydrate intake. Importantly, lipid accumulation was not as responsive to carbohydrate intake as attractiveness and thus was a less-accurate condition proxy. Moreover, males preferentially consumed high carbohydrate diets with little regard for protein content suggesting that they actively increase their carbohydrate intake thereby maximizing their reproductive fitness by being attractive.K E Y W O R D S : Diet choice, Nauphoeta cinerea, nutritional geometry, sex pheromone, sexual selection.

Dietary carotenoids have been shown to confer immunological benefits to some species of animals in which males also use these pigments to attract mates. Thus, the potential exists for an allocation trade-off between the sexual and immunological functions of carotenoids. Food availability may also influence immune system function. The present study examined the effects of carotenoid and food availability on the resistance of male guppies ( Poecilia reticulata Peters) from four wild populations to the parasite Gyrodactylus turnbulli Harris. Intermediate levels of carotenoid ingestion resulted in the lowest parasite loads, which suggests that carotenoids strengthen parasite resistance at low levels but either benefit parasites or suppress host immunity at high levels. Males raised on the high-food level initially had fewer parasites, suggesting heightened innate immunity relative to males raised on the low-food level. Over the course of the experiment, however, the high-food males supported higher parasite population growth rates than the low-food males. The results obtained emphasize the importance of evaluating the effects of diet on multiple aspects of immune system function, and caution against assuming that positive effects of carotenoids on immunity in one context will automatically translate to other contexts.

Despite the important effects of diet and parasite infection on male reproductive behavior, few studies have simultaneously addressed their influence on intrasexual selection (male-male competition). We examined the synergistic effects of 2 naturally varying environmental factors, lifetime food intake and infection, with the monogenean parasite Gyrodactylus turnbulli on the mating tactics and foraging behavior of male guppies (Poecilia reticulata). We allowed fish to interact directly with each other during observations and found that unparasitized males won more intermale contests, courted females more frequently, and received positive responses to courtship displays more frequently than males that had been infected. Infected males devoted more time to foraging and less time to courtship and competition than uninfected males, suggesting that they were energetically limited and could not increase reproductive effort despite their reduced expected lifespan. This interpretation was supported by the observation that greater food intake ameliorated the negative effects of parasite infection on courtship effort. Our results have bearing on how natural variation in food availability and parasite prevalence influence geographic variation in reproductive behavior.

The evolution of male mate choice is constrained by costs of choice in species with a male‐biased operational sex ratio (OSR). Previous theoretical studies have shown that significant benefits of male choice are required, for example, by mating with more fecund females, in order for these costs to be offset and a male preference to spread. In a series of population genetic models we show the novel effect that male mating preference, expressed as a bias in courtship, can spread when females prefer, and thus are more likely to mate with, males who court more. We explore two female preference functions for levels of male courtship, one representing a threshold and the other a weighted female preference. The basic finding generally holds for both preference functions. However, the preference function greatly affects the spread of a male preference allele after the addition of competing males who can court more in total. Our results thus stress that a thorough understanding of the response of females to male courtship is a critical component to understanding male preference evolution in polygynous species.

Objective: Aggression Replacement Training (ART) is a multimodal program aiming at replacing antisocial behaviors by actively teaching desirable behaviors. The program is frequently used and has been provided within a wide variety of settings, but its effectiveness in its own right has not been addressed in previous reviews. This systematic review examines the effect of ART on antisocial behavior in young people and adults. Methods: Published and unpublished literature was searched to identify randomized and non-randomized studies comparing ART for adults and youth with usual care, other interventions, or no intervention. Primary outcomes included recidivism in antisocial behavior, while secondary outcomes were related to social skills, anger management and moral reasoning. Findings: This review identified 16 studies with considerable clinical and methodological diversity. The methodological quality and the post-intervention follow-up of the studies were limited. Almost half of the studies were conducted by researchers who have vested interests in the intervention. Conclusions: There is an insufficient evidence-base to substantiate the hypothesis that ART has a positive impact on recidivism, self-control, social skills or moral development in adolescents and adults. Further research is warranted by independent investigators exploring the effects of ART on clearly-defined target groups using high standard evaluation designs.

Male mate choice in species with conventional sex roles is difficult to explain and has, therefore, been the focus of many recent theoretical models. These models have focused on variance in female quality and, to a lesser extent, male investments/costs associated with mating. In this study, we investigate the costs of courtship and copulation in the polygynous mosquito Sabethes cyaneus. In this species, both males and females possess elaborate ornaments. Previous studies suggest that the most likely explanation for the presence of these ornaments is mutual mate choice. Thus, this system provides an excellent model for exploring the evolution of mutual mate choice in polygynous species. We disentangle the costs of courtship and copulation by monitoring male survival in three groups of males: housed alone (group 1); able only to court females (group 2); or able to court and copulate with females (group 3). We show that males incur a cost of courtship and copulation and that courtship intensity is negatively related to male longevity. Our results suggest that courtship and copulation carry additive costs to males. We discuss the implications of these results in the context of current mutual mate choice theory and suggest that courtship costs may be an unappreciated key factor in the evolution of male mate choice.

Sexual size dimorphism (SSD) is one of the most common ways in which males and females differ. Male-biased SSD (when males are larger) is often attributed to sexual selection favouring large males. When females are larger (female-biased SSD), it is often argued that natural selection favouring increased fecundity (i.e. larger clutches or eggs) has coevolved with larger female body size. Using comparative phylogenetic and multispecies regression model selection approaches, we test the hypothesis that among-species variation in female fecundity is associated with the evolution of femalebiased SSD. We also ask whether the hypothesized relationship between SSD and fecundity is relaxed upon the evolution of parental care. Our results suggest a strong relationship between the evolution of fecundity and body size, but we find no significant relationship between fecundity and SSD. Similarly, there does not appear to be a relationship between fecundity and the presence or absence of parental care among species. Thus, although female body size and fecundity coevolve, selection for increased fecundity as an explanation for female-biased SSD is inconsistent with our analyses. We caution that a relationship between female body size and fecundity is insufficient evidence for fecundity selection driving the evolution of female-biased SSD.

Dietary Restriction extends lifespan in a diverse range of animals, but this often comes at a cost to reproduction. While a number of molecular pathways integral to these relationships have been characterised, we still do not fully understand whether restriction of specific nutrients or calories is responsible. Two recent studies on insects have offered novel insights into this longstanding issue via the application of Nutritional Geometry. This technique promises to significantly advance our understanding of how nutrition influences reproduction and longevity.