Two components of mating behavior, mating latency and duration of copulation, were investigated in Drosophila melanogaster males from three different "nutritional" strains, reared for more than 35 generations on banana, tomato and cornmeal-agar-yeast substrates. Males from different strains did not differ according to mating latency and duration of copulation. Also, the sizes of males from diff...

This paper gives evidence suggesting that one of the two chloroplasts contributed to the zygote of Ulva mutabilis is rapidly destroyed. Chloroplasts in an advanced stage of disintegration can be seen only 4 min after copulation. Radioactive labelling of gametes prior to copulation shows that the disintegrating chloroplast is supplied through the + (plus) gamete, while the chloroplast from the —...

Sexual cannibalism by females and associated male behaviours may be driven by sexual conflict. One such male behaviour is the eunuch phenomenon in spiders, caused by total genital emasculation, which is a seemingly maladaptive behaviour. Here, we provide the first empirical testing of an adaptive hypothesis to explain this behaviour, the remote copulation, in a highly sexually cannibalistic orb...

Neuronal nitric oxide synthase (nNOS) in the medial preoptic area (MPOA) has been implicated in various physiological functions, including male rat copulation. Based on their apparent sensitivity to gonadal steroid manipulation, we hypothesized that nNOS cells contain steroid receptors, and the testosterone-induced restoration of nNOS-immunoreactivity in castrates should accompany the restorati...

After inserting the Cu-IUD and plastic-IUD into the horn of the uterus of rats, vaginal smears were daily observed for twelve estrus cycles, but no abnormal changes were noted. The female rats with the IUD were exposed to impregnation placing together with male rats. Neither the Cu-IUD nor the plastic-IUD affected copulation, and a complete contraceptive result was obtained in these rats. There...

The idea that copulation might increase predation risk is a classic suggestion, but empirical evidence to support it is surprisingly scarce. While some early work found decreased vulnerability to predation during mating, two lab and one very recent field study documented increased predation during mating in freshwater amphipods, water striders and locusts. Decreased vigilance, less efficient es...

We have identified cells in the brain of Drosophila melanogaster that are required to be of female genotype for receptivity to copulation with males. To do this, we determined experimental conditions in which female flies virtually always copulate, then measured the minimum amount of male courtship that is required to stimulate females to indicate their receptivity to copulation. We then observ...