The growth and maturation of the “tarantula”, Avicularia avicularia L.

Abstract

The growth of the theraphosid spider, Avicularia avicularia L. was studied principally by taking measurements of the fang length of exuviae and dead specimens. The relatic ships between fang length and increment at ecdysis and fang length and instar duration were investigated and used to construct a projected growth curve for the species. This suggests that males reach sexual maturity in approximately 13 instars and at a minimum age of about two and a half years. In males the adult instar is terminal and rarely lasts more than three months. Reproductive maturity in females is probably not reached earlier than the XIVth instar or three years from birth. The females continue to moult annually after maturity and have a longevity in excess of seven years. The pattern of colouration shows characteristic changes in early immature life and develops a slight sexual dimorphism in adults. Type II urticating hairs are present throughout life and occur in light and dark forms in the IInd instar. The mean length of the urticating hairs increases during the life cycle and a sexual dimorphism develops in the XIIth or XIIth instar. In adult males the urticating hairs are uniformly barbed whereas in the adult females the barbs are restricted to the proximal end.