Male Widow Spiders Enjoy A Better Love Life Than Previously Thought

Female black widow spiders are notorious for their tendency to eat their mates after copulation, and the female black widow is not the only lady spider to feast on her mate. For example, two species that are closely related to the black widow–the Australian redback spider and the brown widow–often see their males eaten alive post coitus. In fact, the males belonging to these two species will sometimes flip over onto their backs after mating in order to offer their bodies as food to their female counterparts. It seems that the dating life in the spider world is pretty rough. However, researchers have recently observed that the male redbacks and brown widows are able to avoid this gruesome fate by going after young females. But why would that make any difference?

First of all, the mature females belonging to the above mentioned groups of spiders weigh one hundred times more than their male counterparts, so the males don’t stand a chance at survival unless the female already has her belly full of poor male corpses. However, the weight of the young female spiders is on par with the males, so being overpowered and eaten alive is not much of a worry to the males. Second of all, the younger females are much easier to impregnate since they do not require long and drawn out mating rituals, and whichever male chooses to inseminate a young female will usually be the first one to do so, thus increasing the chances for fertilization, and the lucky male gets to copulate yet again. These new findings can be found in the Royal Society’s journal Biology Letters.

Why would the females’ preference for eating males after copulation NOT be disadvantageous for the spider community and evolution as a whole?