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The biology of two Australian species of dinopid spider
Author(s) -
Austin A. D.,
Blest A. D.
Publication year - 1979
Publication title -
journal of zoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.915
H-Index - 96
eISSN - 1469-7998
pISSN - 0952-8369
DOI - 10.1111/j.1469-7998.1979.tb03957.x
Subject(s) - biology , predation , sclerophyll , spider , nocturnal , ecology , creatures , dusk , zoology , natural (archaeology) , paleontology , mediterranean climate
Populations are compared of the E. Australian net‐casting spiders Dinopis subrufus (L. Koch 1878) and Menneus unifasciatus (L. Koch 1878) co‐existing in dry sclerophyll forest. Previous recent accounts of net‐building by Dinopis are confirmed, and it is shown that Menneus constructs its snare in essentially the same way. Whereas Dinopis makes its net in relation to horizontal surfaces and catches prey walking across them, Menneus relates it to vertical grass‐stems and twigs near to the ground, and catches small blattellid cockroaches which run up them (92 % of prey records). Prey‐capture by Dinopis appears to be non‐selective, and includes cockroaches (23%), ants (33%) and other spiders (15%). Both genera are nocturnal and are procryptic by day. Dinopis become active after nightfall, Menneus during twilight. The time taken for net‐construction nevertheless means that both must capture the bulk of their prey after dark. It is suggested that the large posterior median eyes of Dinopis, known to be highly specialized for night‐vision, are used to discriminate prey whose reflectances differ little from those of their backgrounds. It is possible that Menneus locates prey through vibration of the framework of the snare, but the small, unspecialized eyes may perceive prey insects as silhouettes against much lighter surrounds because of the orientation of the snare and the nature of the background.