WHO IS THE LESSER WATER BOATMAN ?

Lesser Waterboatman, Corixa sp.


Lesser Waterboatman, unknown species

ONE FINE DAY IN SPRING YOU ARE STANDING AT THE EDGE OF A CLEAR POND. The rays of the sun touch the sand bottom which, being clearly visible in the shallow parts, disappears in the murky depths. Suddenly a little insect, size of perhaps a centimetre, is sprinting up from the bottom to the surface, remains there a second, shining in the sun, and hurtles back to the depths: there goes the lesser water boatman.

The lesser water boatman is a very common insect in all kind of small waters, they are abundant in many streams and pools. You may find them less in your garden pond, because it lacks a shallow sandy border in most cases. In Europe there about 40 species described.

The lesser water boatman (Latin: Corixa sp.) has to endure it's name as a lower ranking of the (true) water boatman, or backswimmer (Latin: Notonecta sp.) because in a surfacial glance they seem to be very much the same species of animal. We will see however that they are quite different.

One species of the most common lesser water boatman, Corixa punctata measures just over a centimetre and is a fine looking animal: gold coloured back, silvery bubble under the belly, bright red eyes (getting darker on aging), all on a superior streamlined body (see the photo on this page). They can be kept alive in an aquarium quite a while, provided there is some detritus("garbage") on the bottom, because that is where most of them get their nourishment from. Being no predators, they can be kept safely together with other animals from the ditch. First however we have to learn how to distinguish the true water boatman from the lesser. When you see an insect swimming away fast under water with a jerky motion, most of the time this will be either the lesser, OR the true water boatman. They are both bugs and like already written look a lot alike at first sight: streamlined, boat shaped insects of about a centimetre size with long hind legs moving like oars. Most of the time you will first see the true water boatman because it lives right under the water surface. The lesser water boatman, you will see more on the bottom (if that bottom is visible of course), or you may see it just a second, when getting air at the surface.

On the next page there's more on the differences..