Mating ball

Often the ball consists of a single female and many males; a particularly asymmetrical case is that of the red-sided garter snakes which form each spring some of the most populous mating balls observed, in which as many as a hundred males try to reproduce with a single female.

This causes a sexual competition among the first individuals to emerge from brumation to successfully mate before competitors are fully active.

Body contact between members of the ball conserves the group's heat to enable the activity of mating to continue.

[4] Japanese beetles also make large mating balls, of which the occurrence in human spaces contributes to their being commonly regarded as a pest species.

Once the female emerges from the ground, she releases a pheromone which attracts other beetles to form the mating ball.