Water Striders’ Mating Blackmail

August 14, 2010

A creepy yet fascinating insect story from Discover:

Hyper-violent males can sometimes wear the female down but some opt for a subtler approach – they tap intricate rhythms on the water with their legs. When Han and Jablonski discovered these rituals last year, they suggested that the males might be trying to demonstrate their quality, by tapping out the most consistent rhythms. Now, they have another explanation – the tapping is a form of blackmail, a way of coercing sex from the female with the threat of death.

The duo studied the preferences of the backswimmer – a predatory bug that floats upside-down at the water’s surface and listens out for the vibrations of potential prey. When given a choice between a silent male water strider and a mating pair with a tapping male, the backswimmer always headed towards the vibrating duo. And since these predators attack from below, the female was always the one who was injured while the male strode off to tap another day.”

Interestingly enough, here’s a story from 2009 about this exact thing—but in this version the males are said to be “singing” with their feet to impress the females. (That’s mentioned in the first article, but without much detail.) Which is true? Nobody knows—except perhaps the male water sliders…and the backswimmers.