Female cooperation in plug formation in a spider: effects of male copulatory courtship

One of the strongest indications that cryptic female choice is an evolutionary phenomenon of general importance is the widespread existence of male courtship behavior during copulation. It has been presumed that such copulatory courtship functions to induce female reproductive behavior that favors the male's reproductive interests, but this function has seldom been demonstrated. Here, we examine the possible effects of male copulatory courtship in the spider Leucauge mariana (Tetragnathidae) on whether a female will aid the male in forming a copulatory plug, thus reducing the chances that future mates will be able to inseminate her. Greater numbers of 2 behavior patterns by the male during copulation, rhythmic pushing on the female's legs with his front legs, and repeated short insertions with his genitalia were associated with increased chances that the female would cooperate in plug formation. This confirms that these behavior patterns do indeed function as courtship.