Estimation method of instars of Linyphia emphana (Araneae: Linyphiidae) using body sizes

Abstract

To estimate instar of Linyphia emphana Walckenaer, the relationships between body sizes and instars were investigated under three different feeding conditions by rearing in plastic cases. Three body size parameters of each instar of the rearing spiders, i.e. posterior width of median ocular area, width of eye area, and width of carapace, were measured. Of these, the posterior width of median ocular area steadily increased 0.03 mm (range 0.02 mm) after each ecdysis, while other body sizes were remarkably varied. The result of this study shows that posterior width of median ocular area was the best indicator to estimate the instars of this species. © 1992, Arachnological Society of Japan. All rights reserved.