The Bionomics of Otiorrhynchus cribricollis, Gyll

Abstract

(1) The history of Otiorrhynchus cribricollis in Australia is traced and records of its distribution in other countries are cited.(2) Methods used in the experiments are described.(3) The incubation period of the egg was found to vary between 14 and 37 days. The average was 22·3 days.(4) The habits of the larva are described. Dyar's Law was applied to determine the number of instars, which was found to be 10.(5) The normal duration of larval life is from May to October or a period of about 5 months.(6) About 10 per cent. of the larvae aestivate through one summer. These have a larval life of about 17 months.(7) Normal life of the adult is from November to April, about 5 months, but some (about 11 per cent.) hibernate through one winter and thus live 17 months.(8) The adults feed in two seasonal periods separated by an interval of about 6 weeks, during which time they are inactive.(9) The adults have been observed to feed upon 21 different plants, representing 12 different families.(10) Most of the eggs are laid in the autumn, but a few are laid in the spring.