Water Spider
  Megadolomedes australianus
  Family: Pisauridae  ID: Koch, 1865
Water Spider (Pisauridae)
Water Spider (Pisauridae)
Water (or Nursery) Spider
Water Spider (Pisauridae)

Habitat and Biology
Water spiders are found along the edges of swamps, marshes, creeks, ponds and other bodies of water throughout eastern Australia and Tasmania. They are vagrant hunters and usually feed on insects found near the water's edge or on the surface but they have been known to take tadpoles, fish and frogs. They have hairs on the tips of their feet which enable them to walk on water but they can also dive and swim beneath the surface to catch prey. Air trapped in the hairs around their spiracles allow them to stay submerged for a long time. Like the wolf spider, the female water spider carries her egg sac with her. However she carries it underneath her body, holding it in place with her jaws and palps. (Wolf spiders drag their egg sac behind them attached to the spinnerets). When the spiderlings are ready to hatch, the water spider builds a nursery web of silk and leaves among reeds and rocks by the water. She guards the spiderlings until they can fend for themselves then resumes her vagrant lifestyle.

Male: Similar to female.
Female: Body various shades of brown with a flecked or mottled pattern. Some species have yellow or white and dark brown longitudinal stripes on the cephalothorax and a series of white spots on the abdomen.

Similar in shape and colour to a wolf spider but longer legs, cephalothorax oval and abdomen pointed behind. Hairs on the tips of the feet enable the spider to walk on water. Male smaller than female with long legs.

Body Length
Male: 15-20mm
Female: 20-30mm

Web type
Does not build a web.

This spider can be very aggressive if disturbed and although it is known to give a painful bite, symptoms may include local pain and swelling.

© Museum Victoria Australia