How females and males differ in performance in object recognition tasks appears to vary among mammalian species, with female superiority found in the laboratory rat and humans but not in the laboratory mouse. Here we assessed sex differences in object recognition in C57BL/J6 mice by varying the similarity between objects to be learned. Females outperformed males in object recognition when the n...

According to their activity profiles tick pheromones can be characterized as assembly pheromones, aggregation/attachment pheromones, pre-attachment or pre-feeding pheromones, attractant sex pheromones, contact sex pheromones, fecundity-reducing pheromone and various ungrouped pheromones. This paper gives a short review of the chemical characteristics, biological roles, and activity periods as w...

Sex-ratio distorters are found in numerous species and can reach high frequencies within populations. Here, we address the compelling, but poorly tested, hypothesis that the sex ratio bias caused by such elements profoundly alters their host's mating system. We compare aspects of female and male reproductive biology between island populations of the butterfly Hypolimnas bolina that show varying...

Sex-role evolution theory attempts to explain the origin and direction of male-female differences. A fundamental question is why anisogamy, the difference in gamete size that defines the sexes, has repeatedly led to large differences in subsequent parental care. Here we construct models to confirm predictions that individuals benefit less from caring when they face stronger sexual selection and...

The personality and hormonal correlates of mate poaching (attempting to steal another person's partner away) and of the target of the seducer (the mate poached) were examined in a sample 154 undergraduate university students (91 females; 63 males). Thirteen variables were modeled into two regression equations to predict and profile mate poachers and the mate poached. Findings revealed that (1) ...

Hatchling sex ratios in the loggerhead turtle Caretta caretta were estimated by placing electronic temperature recorders in seven nests at Kuriat islands (Tunisia) during the 2013 nesting season. Based on the mean temperatures during the middle third of the incubation period, and on incubation duration, the sex ratio of hatchlings at Kuriat islands was highly male-biased. Presently, the majorit...