Nature Bulletin No. 221-A    March 12, 1966
Forest Preserve District of Cook County
Seymour Simon, President
Roland F. Eisenbeis, Supt. of Conservation

****:WATER BUGS

It is fascinating to lie in a boat or on a log at the edge of the water and 
watch the drama that unfolds among the small water animals. Among 
the star performers in small streams and ponds are the Water Bugs. 
These are aquatic members of that large group of insects called the 
"true bugs", most of which live on land. Moreover, unlike many other 
types of water insects, they do not have gills but get their oxygen 
directly from the air. Those that do go beneath the surface usually 
carry an oxygen supply with them in the form of a shiny glistening 
sheath of air imprisoned among a covering of fine waterproof hairs. 
The common water insect known to small boys at the "Whirligig Bug" 
is not a water bug but a beetle.

All kinds of water bugs have needle-like sucking beaks with which all, 
except the Water Boatman, attack and feed upon other small water 
animals, and upon insects which fall in the water from overhanging 
vegetation. With these sharp beaks they can inflict painful stinging 
bites through the tough skin of human hands. Some kinds dive or 
swim. Others prowl among underwater plants and trash. A few ride 
the surface film. Water boatman, in contrast to the others, feed mainly 
on vegetable ooze, algae, and the like.

Young water bugs are much like their parents, only smaller. For 
instance, young Water Striders look like frisky little spiders. All kinds 
spend the winter as adults. Some hibernate in underwater nooks, while 
others remain rather active. They regularly live a year or more. When 
the ice begins to melt in spring they are often the first active water 
creatures seen.

The largest of all the diving and swimming bugs are the Electric Light 
Bug -- so called because so many of them used to fly to the old-
fashioned arc lights -- and the Giant Water Bug; both wide flat-bodied 
insects which may reach a length of 1-1/2 or 2 inches. Both have the 
front legs fitted for clutching and the other two pairs flattened and oar-
like for rapid swimming. They devour dragon flies, and often attack 
and kill minnows, small frogs and tadpoles. The female of the Lesser 
Water Bug, instead of fastening her eggs to plants like most of the 
others, glues them on the back of her husband, often in spite of his 
vigorous opposition.

Most conspicuous and commonly known are the Water Striders or 
Water Skaters. These ride on top of the water, with only their feet 
making dimples in the surface film. They have very long legs and 
slender bodies, like boats with long oars. They skip about rapidly on 
the surface but are practically helpless on land. Of the several kinds, 
some have short wings -- others none at all. One small species prefers 
rapid water where it uses an oar-like fan of bristles on the middle leg 
to swim against the current.

The little Water Boatmen, being vegetarians, spend much of their time 
on the bottom. Their long oar-like hind legs are flattened for 
swimming and diving but they also fly well. The females of some 
kinds lay their eggs on the backs of crayfish. The Backswimmers are 
similar to the water boatmen except that they commonly hang head-
downward from the surface and always swim on their backs. The male 
can make a squeaky noise by rubbing its face with its front legs.

The Water Scorpions have two long tail filaments, like a snorkel on a 
submarine, through which they breath as they lurk beneath the surface, 
waiting for the aquatic insects, snails and small crustaceans upon 
which they prey. The long slender stick-like Marsh Treaders, or Water 
Measurers, walk slowly over the water plants at the edges of ponds, as 
if measuring each step.

Signs of spring: skunk cabbage and water bugs!