Pisauridae

Common Name

Nursery Web Spiders

Overview

Pisauridae, commonly known as nursery web spiders, is a family of araneomorph spiders notable for their unique maternal care behaviors. These spiders are often confused with wolf spiders but can be distinguished by their eye arrangement and web-building behaviors.

Taxonomy

Key Characteristics

  • Eyes: Two rows of eyes with the posterior median eyes often large and forward-facing.
  • Size: Medium to large-sized spiders, with body lengths ranging from 9 to 25 mm.
  • Coloration: Generally brown or grey with distinct patterns and markings.
  • Legs: Long and strong, used for hunting and carrying egg sacs.
  • Silk Usage: Constructs nursery webs for egg protection, rather than webs for prey capture.

Life Cycle

  • Eggs: Laid in egg sacs and carried by females.
  • Spiderlings: Hatch within the nursery web, which provides protection until they are ready to disperse.
  • Development: Gradual metamorphosis through several molts.
  • Maturity: Reach adulthood typically in one to two years, depending on environmental conditions.

Behavior and Ecology

  • Hunting: Active hunters, do not rely on webs to catch prey.
  • Maternal Care: Females carry egg sacs in their chelicerae and build nursery webs to guard spiderlings.
  • Habitat: Found in diverse habitats, including grasslands, wetlands, and forest edges.
  • Diet: Insects and other small arthropods.

Notable Species

  • Pisaura mirabilis: Widespread in Europe, recognizable for its dedication to maternal care.
  • Dolomedes tenebrosus: Known for its aquatic hunting techniques and ability to catch small fish.

Conservation

Generally not endangered but habitat destruction and pesticide use can impact local populations. Preservation of natural habitats is beneficial for their conservation.

Significance to Humans

While they may look intimidating, nursery web spiders are beneficial because they help control insect populations. They are also of interest to researchers studying maternal care in spiders.

Fun Facts

  • Aquatic Skills: Some species, like Dolomedes, are capable of walking on water and diving to catch prey.
  • Parental Care: The name "nursery web spider" comes from the unique behavior of building protective webs for their young.
  • Mating Rituals: Males often offer prey to females as a nuptial gift to prevent being eaten after mating.
  • Super Vision: Their eye arrangement gives them excellent vision, aiding in hunting and avoiding predators.
  • Jumping Ability: They can leap significant distances to catch prey or evade threats.