Water crickets (Velia caprai) on a brook
The dimples under the legs are casting four shadows and have remarkable light
stripes. Mark the flatworms.
Three pictures of Water crickets, top view. The long middle legs deliver the propulsion.
THE Water cricket IS A STOUT SURFACE BUG: HE RUNS ON RAPID
STREAMING WATER, SOMETIMES IN MIDWINTER. Water striders are also able to walk on streaming
water, some species even prefer this, but the Water cricket can handle more rapid streaming
waters. Yet even the Water cricket prefers the more quiet nooks, if the waters get too rushy
then even this species leaves. Often they are hidden in the growth of the border and seem
disappeared from one day to another. On the brook they stand in small groups like dark
spiders, staying put with short jerky rowing movements on the quick water in an amazing way.
Every now and then one of them may dive
under water, the Water cricket is the only
surface bug able to do this. They can also crawl along a water plant to a submerged
position. Surrounded by a bubble of air they can stay under for a while. Let's have a
closer look at the Water cricket with the pictures on this page, that were all made in the
"Sprengendal" (Spring valley) near Ootmarsum, in the Netherlands. On the right:
four Water crickets on a stream. If you look closely, you can see that the middle legs are
held up like a pair of oars. The front and hind legs are sharply bent backward, the feet
like sled irons longitudinal with the body. In this way they have the lowest resistance to
the rapid flowing water, they are a bit like skaters who stand still while the ice moves
fast under them. The middle legs only touch the surface for short rowing motions (see also
the smaller pictures below left). In sufficient light the Water cricket is beautifully
marked with white spots on black and a pair of red seams that have pointed ends. Most
specimen are wingless, sometimes an individual with wings appears. There are no half winged
specimens known. In Europe there is
Velia caprai, older name:
Velia currens.
Further there is
Velia saulii which looks very much like the other species.
Water crickets feed on insects that have fallen on the water. They can steal on these by
ejecting a fluid that spreads quickly over the water surface like camphour and so gives the
Water cricket a "silent running". Water-crickets make no sound, they bare the name
just because of their visual resemblance with crickets. Some
Lesser Waterboatman species can make sound however, and for this
sometimes confusingly also are called "water crickets".
Like all true bugs, Velia has partial metamorphosis. The young bugs (nymphs)
resemble the adult. In spring the nymphs crawl out of the eggs and after five instars, they
have become imagos. There is one generation in a year. Below are two pictures of
Velia nymphs. (I mistakenly showed these for years as nymphs of
Microvelia).