Sometimes, preventing your partner from going off and pumping someone else can be a bit of a drag. It might even entail hanging out with them for a post-copulatory period (often known as ‘mate harassment’, although I kind of wish my girlfriend* would stop referring to it as that).
The males of a number of species - including the rather adorable buff-tailed bumble bee Bombus terrestris, above - have developed a handy little technique whereby they secrete a special fluid into a female’s genital tract at the end of copulation. This fluid hardens to form a ‘mating plug’. While females can expel them after a period of time, it just might be long enough that this first male’s sperm get a bit of a jump on the next guy to try his luck. It’s also thought that some of the chemicals in these mating plugs may make females less receptive to further matings for a little while!
All of which gives our plucky hero more time to go and do what he does best (e.g., watch ‘the game’, get more matings, or sting some nosy researchers in the face).
*I’m not telling her about this blog
Photograph used under a creative commons licence, and courtesy of Africa Gomez at http://abugblog.blogspot.com/