The prey of web-building spiders compared with feeding experiments (Araneae: Araneidae, Linyphiidae, pholcidae, Agelenidae).

Feeding experiments with 2,520 prey animals show differences in consumption rate and palatability for four spider species (Zygiella x-notata, Linyphia triangularis, Tegenaria atrica, Pholcus phalangioides). A possible protection against predators by chemical defence is discussed with special regard to 30 species of Heteroptera. Chemical weapons possess an astonishingly low deterrent effect whereas thick chitinisation (Coleoptera) is found to give very effective protection. Studies of the actual prey of these webbuilding spiders gave similar results in Araneidae and Linyphiidae. Nematocera and Homoptera are the most important prey group. Hymenoptera, Coleoptera and Brachycera were seldom caught. In contrast to this, the prey of Tegenaria and Pholcus consists mainly of Brachycera, Coleoptera and Hymenoptera, whereas Nematocera and Homoptera are rarely caught. The prey animals are mostly of small size. Only Pholcus and Tegenaria catch larger specimens. An ecological classification of the prey of Linyphiidae and Araneidae shows high percentages of phytophagous and detritophagous insects. Compared to the potential prey (trap data), predators, parasites and pollinating insects are underrepresented in the actual prey.