nursery-web spider

nursery-web spider, (family Pisauridae), any member of a family of spiders noted for the female spider’s habit of making a protective nursery web for the young and standing guard over that web. Species of nursery-web spiders are found nearly worldwide. Commonly found near the water, many species can walk on still water surfaces and some are even able to escape predators by diving below the surface. Most nursery-web species are medium to large in size, and are sometimes confused with wolf spiders. Members of the genus Dolomedes, the most common North American genus, can have a leg spread of 7.5 cm (3 inches).

Nursery-web spiders may engage in sexual cannibalism, meaning the female spider eats the male after mating. To reduce this risk and hopefully satiate her appetite, some males present the female with a meal, such as a fly wrapped in silk, as part of the courtship. If the nuptial gift is deceptive, such as an empty silk package, the male generally fails to secure mating and may be attacked and consumed by the female. When mating is successful, the female spider lays a few hundred eggs in a silken egg sac, which she carries in her mouthparts until the young spiders are almost ready to emerge. She then attaches the sac to a plant, ties leaves around it with silk, and remains to guard the young from predators.