He saw that, whereas females groomed males and other females for social and political reasons — to affirm a friendship or make nice to a dominant — and mothers groomed their young to soothe and clean them, when an adult male spent time picking parasites from an adult female's hide, he expected compensation in the form of copulation, or at the very least a close genital inspection.
Direct sperm transfer in the form of copulation bypasses the risk of environmental damage in many more derived forms (Selden and Edwards 1990).
At least two species display male alternative reproductive tactics in the form of sneaked copulations, P. microps (common goby) [ 12, 39, 40] and P. minutus [ 24, 41] and at least one species, the marbled goby P. marmoratus, appears to lack male alternative reproductive tactics as judged by gonadal analyses [ 25].
Of all the bizarre forms of animal copulation, only one has earned the description "cephalo-traumatic".
Included in such lists were nightmare demons, demons formed from the semen of copulation, and demons who deceived persons into believing that they could perform transvections (nocturnal flights to sites of sabbats, alleged rites of witchcraft).
During each visit, we recorded the color-band combination of attending adults, the stage of nest building, the presence of eggs and chicks and the behavior of adults in the form of incubation, nest building and copulation, variables that we used to confirm pair identity.
Seminal secretions produced in the male accessory glands (MAGs) are transferred to the female atrium (uterus) during copulation in the form of a gelatinous 'mating plug', which is digested within 24 hours after copulation [ 12].
The spermatophore is formed during the first two minutes or so of copulation, after which the tube extends from the male genital organs to the spermathecal duct of the female.
Biological barriers to interspecies hybridization can occur in any form of male - female incompatibilities prior to or after the initiation of copulation.
First, we tested whether copulation duration is a form of reproductive investment that responds to variation in the OSR as predicted by sperm competition game models.
We staged matings under different sex ratio conditions, and provide evidence that copulation duration is a form of male reproductive investment that responds to the perceived intensity of sperm competition as predicted by game theoretical models.
