Foraging strategy of nocturnal orb-web spiders (Araneidae: Neoscona) with special reference to the possibility of beetle specialization by N. punctigera

Abstract

To clarify the foraging strategy of nocturnal orb-web spiders, we examined the relationship between prey items and foraging traits in four Neoscona species that spin typical orb-webs. Taxonomic composition of prey differed markedly among species; beetles occupied about 50% of prey in N. punctigera and N. scylla. As beetles are generally heavier than other prey, these differences could be due to the differences in kinetic energy absorption ability of webs and/or web stickiness. Comparison of the sympatric two species (Neosocna punctigera and N. mellotteei) with similar body size supported the above inference; mesh density and silk stickiness were higher in N. punctigera that captured more beetles, while microhabitat and other foraging traits were similar. These results suggest specialization to beetles in some nocturnal orb-web spiders. ©Arachnological Society of Japan.