Foraging Specialization in Orb-Weaving Spiders

摘要: Previous studies indicate prey—specific attack behaviors in orb—weaving spiders. This study explored functional relationships between the morphology of contrasting orb—weaver species and their capabilities. Araneus trifolium Argiope trifasciata were observed attacking acridid Orthoptera, calyptrate Diptera, Lepidoptera laboratory. Diets habitat use spiders field determined by surveys. Distributions prey types trapping. captured Orthoptera more quickly than did Argiope, but was successful capturing this type. There no time differences spider on dipterans lepidopterans, these successfully. Attack times do not appear to limit intake rates field. Spider web design interact causing above behavioral differences. builds its high, open sites, usually herbaceous vegetation. tends build low sites both grassy Prey distributions are such that each is found most often where successfully type relatively abundant. Predation physiological stress may also select for use. If results extended other species, following predictions arise. Spiders with short, stout legs, large fangs, simple, open—meshed webs (such as Araneus) should specialize innocuous, rapidly escaping (Diptera Lepidoptera). long small low, densely meshed, ornamented Argiope) dangerous, slowly insects (Orthoptera, Homoptera, Hymenoptera).