Male orb-weaving spiders are eaten after mating, but they get to choose the female spiders that get to devour them, a new study found.

Ideally, the females get to choose which male spider they mate with but biologist Eric Yip from Ben-Gurion University of the Negev in Israel and colleagues found that in the colonies of Cyrtophora citricola spiders from the Mediterranean, the opposite happens — the male spider surveys the females and chooses which of them he is going to be his mate.

Mating Behavior

Yip said that there might be two reasons the male spiders practice this behavior. Firstly, they only have one chance to mate. Secondly, males live with scores of females in their colonies and they encounter hundreds to thousands of females daily. This means that they are more likely to be devoured even before they can look for their partner, if they are not the one to choose.

The experiments in the study showed that indeed males are choosy when it comes to their partners and they look for certain traits before choosing whom to mate with. They observed that male spiders can spend days in the webs of the females without even mating, even if the female spider was a virgin.

"The ideal female is a very well-fed, recently molted female to adulthood," said Yip. "So she's got a lot of resources for eggs, she's a virgin so he may not have any competition for those eggs with other male sperm, and she's young, so she hasn't expended any of these resources that she's gathered throughout her juvenile life."

They also observed that older male spiders are less choosy, probably because they have lesser time to find a partner to mate with.

Self-Preservation

The species show 100 percent rate of sexual cannibalism and perhaps the male's way of preserving itself is by choosing a mate that would produce more eggs and transfer more of his sperm. The male spiders choose well-fed female spiders because they tend to have more eggs. They allow the females to eat them so the females can feed longer, produce more eggs, copulate for much longer and transfer more sperm.

Darwin's bark spiders, however, evade sexual cannibalism by performing oral sex on their partners.

The study was published in PLOS ONE on June 1.

Photo: Dinesh Rao | Flickr