Lets Talk Bugs
by Tom Lager

Did you see the weather forecast? It is going to be cold out there – that means the water in our streams, ponds and lakes will get stiff. How does this relate to bugs – well as you have seen some bugs can skate, on water that is.

They are members of the Gerridae family – “water striders”. As you can see below they are long (3-20mm) and narrow in appearance with long oar-like legs. Adults may be winged – although difficult to observe.

Fig. 1. Water-striders (Gerridae) from pond in the Thunder River, WI

The characteristic that I find most interesting is their ability to skate or walk on the water’s surface. In fact if you look carefully at the picture, you can see the water surface is deflected by their weight. Walking is accomplished by the velvety hydrofuge hairs on their tarsi (feet), which act to repel water much the same way that good quality hackle floats a dry fly.

Their movement across the surface is in a fashion reminiscent of oaring. Those striders which commonly inhabit streams and riffles have exaggerated hairs – longer and stiffer than their still water relatives. The sketch below gives you the idea. This tuft of hairs acts to grab the surface and permits the strider to push forward.

Striders are predaceous on a wide variety of organisms found in or on the water surface either from the aquatic habitat or accidental introduction from terrestrial habitats. They are very agile creatures that can swiftly seize prey. Striders have piercing mouth-parts, with which they stab prey and inject digestive juices and you can imagine the next step – slurp – they suck out the soup! Have you ever thought as you are quietly creeping along a stream, sneaking up on brookies, that right next to you the “striders are slurping soup”!?

Typically water-striders over winter in the adult stage and lay eggs in spring. They are common inhabitors of aquatic environments around the global from temperate to tropical areas – some even in marine habitats.

Fig 2. Broad shouldered water-strider and hydrofuge hairs.

I have never observed trout feeding on them (let me know if you have). To me these critters are a neat part of His creation. I have seen them in all but the smallest streams; in fact, I have even seen them on top of my car when parked near a river in northern Minnesota. At the time I had a dark red or some other dark shiny color (I don’t recall the exact color), but apparently the strider mistook the dark shiny surface to be water and landed on it. I have seen aquatic beetles do the same thing as they fly about searching for new habitats.

Remember as you walk the streams or ice fish – take the time to look down the hole – you may see some of “the bugs”.