Seminal Fluid Mediates Ejaculate Competition in Social Insects

Abstract

Sperm Wars Some female insects mate on only one day of their life, but then they may mate with multiple males and store the sperm, sometimes for years. But as the mates compete for mates, so their sperm compete for ova, and competition between ejaculates can result in the destruction of sperm inside multiply mated females. But females need to select the sperm they want and to maintain stores of viable sperm to ensure a lifetime's fertility. Den Boer et al. (p. 1506 ) compared species of bees and ants with queens that either mate once or mate multiple times, and found that sperm competition has driven the evolution of compounds in the male accessory gland that protect a male's own sperm while damaging another male's sperm. To counteract the male effect, queens produce compounds that mitigate sperm destruction and maximize the number of her offspring.