The Water strider

WATER STRIDERS IN THE SUMMER, the time when they are very busy, on the first mild days the males are already continuously hunting the females. Often they claim a territory, from which other males are chased away. Some males do not hold territory but just stay around and wait for a good opportunity to get a female. And there are days that all males operate without a territory. Of course much research is done on these habits. The males lure the females by generating vibrations in the water surface, which are detected with the legs. The Water strider male is a real "draufgänger": with a jump he lands on the back of the female, which resists heavily against this sexual harassment and tries to shake the rapist off by jumping and turning on her back like a wild mare. Why she does this? Maybe to allow only the strong males to mate - as part of the "survival of the fittest". The males of some species have a little help from there antennae which are reformed to hooks to get a good grip on the female. On the web you can find a beautiful picture of a struggling pair of Water striders with an article on this subject, see the link at the bottom of this page. When the female gives in, the mating can start as on the picture on the left. The male is carried by the larger female, often for hours. The eggs are glued to plants and branches on the border. Some species crawl under water for this! When the eggs hatch the surface is crawling with very tiny larva, that sit on the water like a flock of little spiders. They seem to exist only of two crossed tiny wires. This image is caused by the abdomen, which is amazingly shortened in the early instars of the larva, it almost seems as if the animal has just a head and thorax, as can be seen on the picture on the right. The larva mold a few times and then the abdomen grows more elongated again, as can be seen on the picture under left. The growing wings reflect the sunlight, they seem to have a silvery coating. We are writing larva here, but bugs have an incomplete metamorphosis and so the young animals strongly resemble the adults. After five instars the larva have turned into adult Water striders. At the end of the summer no larva can be found.

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WEBLINKS:
Article: "battle of the sexes" with a nice photo of wrestling Water striders.