Diet and foraging behaviour of huntsman spiders in the Namib dunes (Araneae: Heteropodidae)

Authors

  • J. R. Henschel

    1. Desert Ecological Research Unit, P.O. Box 1592, Swakopmund, Namibia
    Search for more papers by this author
    • *Zoology III, Biozentrum am Hubland, Wiirzburg University, D-97074 Wiirzburg, Germany


Abstract

Diet and foraging behaviour of three species of burrowing huntsman spiders, Leucorchestris arenicola, L. steyni and Carparachne aureoflava, from the Namib dunes were investigated over a three-year period. These nocturnal spiders are polyphagous predators that prey on more than 97 species of insects, arachnids and reptiles. Most prey were nocturnal or crepuscular tenebrionid beetles, moths and weevils. Diet varied regionally owing to faunal differences, but was relatively constant over seasons. Although spiders occasionally captured prey greater than themselves, average prey length was about two-thirds their own length. Prey size was not strongly related to spider size. Larger spiders were both cannibals and intraguild predators. Foraging pattern of L. arenicola was variable with several nights of activity followed by one or several nights of rest. Spiders foraged within 3 m of the burrow, but occasionally pursued prey or neighbouring conspecifics further. Large prey (> 3 mm) were captured approximately every five weeks in summer and every seven weeks in winter, producing an average annual consumption of ≅ 10 prey/spider. Namib huntsmen are sit-and-wait predators within narrow territories waiting for the fortuitous arrival of prey and are thus unlikely to limit prey populations. They compensate for food shortages by cannibalism, thus restricting their own population.

Ancillary