Black goby territorial males adjust their ejaculate's characteristics in response to the presence of sneakers

In many species, males can rapidly adjust their ejaculate performance in response to changing levels of sperm competition, an ability that is probably mediated by seminal fluid adaptive plasticity. In the black goby, Gobius niger , territorial males attach viscous ejaculate trails to the nest roof, from which sperm are slowly released into the water during the long-lasting spawning events. Sneaker males release their sperm in the vicinity of the...