Sexually selected ornaments and weapons are exceptionally variable, even between closely related species. It has long been recognized that some of this diversity can be explained by differences in mating systems between species, but there remains substantial variation between species with similar mating systems. We investigated the roles of sex ratio (measured as operational sex ratio, OSR) and...

According to the ‘mating intelligence’ theory by evolutionary psychologist Geoffrey Miller, human morality is a system of sexually selected traits which serve as costly signals to the other sex about one’s fitness and readiness to take care for possible offspring. Starting from the standard prediction of evolutionary psychology that sexual selection produces psychological sex differences in hum...

The influence of three types of diets on the number and symmetry of sex comb teeth (male secondary sexual character) as well as on behavioral trait (mating success) was tested in fruit fly in laboratory conditions. Mating experiments were conducted with three Drosophila melanogaster strains reared more than one year on different food. The quality of the diet itself had no influence on the numbe...

Over 90% of men and women marry, but as many as 50% of married men and women have affairs. Thus, in a self-reported study of ideal mating arrangements, in which costs associated with infidelity are eliminated, it was hypothesized that men and women would prefer a mating arrangement of monogamy with the option of casual, extra-pair sex. Unexpectedly, men and women (n1⁄4 463) overwhelmingly prefe...

Recent comparative genomics and mutational studies of the genes regulating mating and meiosis in fungi provide new insights into not only the variability of the key genes, but also the plasticity of the regulatory circuitry in the evolution of mating systems.

1. Fig wasps have proved extremely useful study organisms for testing how reproductive decisions evolve in response to population structure. In particular, they provide textbook examples of how natural selection can favour female-biased offspring sex ratios, lethal combat for mates and dimorphic mating strategies. 2. However, previous work has been challenged, because supposedly single species ...

Body weight has risen in defiance of health and appearance norms. This is framed in terms of the problem of time-inconsistency and self-control. The social epidemics of overeating and slimming were driven by market forces and the psychology of eating: restrained eating was easily disinhibited by the stresses of new rewards. For men, the rise in body weight was associated with the decline of fam...

Ciliate mating systems are highly diversified, providing unique opportunities to study sexual differentiation and its implications for mating dynamics. Many species of ciliates have multiple (>2) sexes. More sexes may mean more choice and an opportunity for evolution of preferential mating. We asked if the multiple sexes of the ciliate Tetrahymena thermophila mate preferentially among each othe...