Water striders - skating on water.

Water striders belong to the Hemiptera, or true bugs.  They are one of the few organisms that take advantage of water's surface tension.  They literally "skate" on the surface of the water without themselves actually getting wet.  The rear four legs are used to achieve this while the front two catch prey and hold it for eating.

Water has very strong cohesive forces, but no more so than at the water's surface when it comes into contact with air.  The hydrogen bonds are especially hard to break here as the atmosphere offers no substitute.  The water strider's back four feet are covered with hydrophobic hairs that repel water.  This allows the insect the ability to stand on the water's surface without breaking its cohesion.

The above water strider is a juvenile; it's wings have not fully developed yet (they will eventually cover the abdomen after the final moult.   Each instar (period between moults) lasts about 7-10 days.  When they become adults they can fly and will look for new feeding/breeding areas.  I have found adults in small puddles miles away from major water bodies.

They eat any insects that may fall into the water, living or dead.  All bugs have piercing mouthparts called beaks that push into an organism's flesh and then removes fluids through its hollow core.  Digestive juices are injected to facilitate the liquidation of the meal's interior.  Although they don't generally bite people, other Hemiptera such as giant water bugs can produce infuriatingly painful wounds.

Water striders are helpful organisms.  They can actually extract mosquito larvae from the water when they rise to the surface to breathe.  I didn't know that; they just went up a notch in my opinion of them.  Cool.

Thanks for reading.

Eric Svendsen     www.ericspix.com