Male Black Widow Spiders Like Mates Fat and Chaste

Male black widows try to find females who are well fed and unmated as they are then less likely to be cannibalized.

It was known that female black widow spiders practice sexual cannibalism - this means they often eat the male shortly after mating. It had been assumed that mate choice was driven by the female. But new research by Dr. Emily MacLeod, a Post-Doctoral Researcher in the Department of Biological Sciences at the University of Toronto, Scarborough, has found that it is the male who makes the mate choice. In fact, using pheromonal cues mostly from her web, he picks up two important qualities that will increase his chances of avoiding being eaten after mating. The male can detect if the female is well-fed, and a virgin. An unfertilized female who is not hungry is less likely to cannibalize her mate.

Related Links

• Paper in Animal Behaviour