One of those oddball factoids you stumble across quite by accident, “..why does aquatic insect activity peak at dawn and dusk?” I’ve heard many explanations, assuming the lower air temperatures played the largest role in mating behavior.

It appears that low light conditions actually allow the bugs to detect water better – so the egg laying females can put the payload where it belongs.

The Journal of Experimental Biology outlines the issues in a paper, citing temperature, less wind, less predators, but water detection is the primary factor.

Since the rate of dehydration is proportional to the surface-to-volume ratio, small-bodied aquatic insects become easily dehydrated during flight if they cannot find a body of water within 1 h.

That doesn’t give them much time, and also explains why a neighboring creek may have an entirely different population of insects – it’s too far to fly without spinning to earth.

You learn something every day…

Technorati Tags: water detection, aquatic insects, mating flight, egg laying, dehydration