In order for the male courtship traits to honestly signal quality they need to be condition-dependent. Moreover, if these traits capture genetic variation in condition they should resemble life-history traits in being subject to strong directional selection and, consequently, suffer strong inbreeding depression. In this study we investigated the effect of high inbreeding on male attractiveness ...

The female Afghan pika is known as a species of copulatory ovulators exhibiting persistent estrus unless copulatory stimuli are employed. The plasma LH concentration rose quickly after copulation, peaked at 6 h and descended thereafter until 12 h. Before copulation (estrus), immunoreactive LH-containing cells of the pituitary in this species were filled with numerous large electron dense secret...

Females of most animal species are usually inseminated by more than one male, which allows sperm from different males to compete for fertilization. To prevent invasion of sperm from other males, Drosophila males elicit a rejection behavior in their mates after copulation. Using paired mutant males that, for the lack of accessory glands, are sterile, we show that this rejection behavior is induc...

Dopamine (DA) activity in the medial preoptic area (MPOA) contributes to the control of male rat sexual behavior. We tested (1) whether extracellular DA increases during precopulatory exposure to an estrous female and during copulation, (2) whether exposure to another male increases extracellular DA, (3) whether motor activity during copulation accounts for increased DA levels, and (4) whether ...

In many animal species, copulation involves the coordinated release of both sperm and seminal fluid, including substances that change female fertility and postmating behavior. In Drosophila melanogaster, these substances increase female fertility and prevent mating with a second male. By using a PGal4 strain, we targeted together with other cells a dozen cholinergic neurons found only in the ma...

In the present experiments, the dose-response effects or the dopamine (DA) receptor antagonists haloperidol, pimozide, clozapine, sulpiride. and metoclopramide, were assessed on patterns of copulatory behavior in intact, sexually active male rats with a high level of sexual experience and performance. The typical neuroleptics haloperidol (0.01-0.5 mg/kg) and pimozide (0.1-5.0Omg/kg) dose-depend...

Extracellular concentrations of dopamine (DA) and its metabolites dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) were examined concurrently, using in vivo microdialysis, in the nucleus accumbens and dorsal striatum of sexually active male rats during tests of locomotor activity, exposure to a novel chamber, exposure to sex odors, the presentation of a sexually receptive female, ...

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 thi...

Oral sex is widely used in human foreplay, but rarely documented in other animals. Fellatio has been recorded in bonobos Pan paniscus, but even then functions largely as play behaviour among juvenile males. The short-nosed fruit bat Cynopterus sphinx exhibits resource defence polygyny and one sexually active male often roosts with groups of females in tents made from leaves. Female bats often l...

Sperm release and sperm storage were examined in the spiny orbweaver, Micrathena gracilis. This species shares characteristics with other spiders that show a first-male advantage for egg fertilization. Male M. gracilis differentially released sperm to virgin females. Sperm release was not related to female age or copulatory duration. In this species, a complete mating between a pair requires tw...