SUPPRESSION OF REPRODUCTIVE DEVELOPMENT AND LONGEVITY IN THE RED-SHOULDERED LEAF-BEETLE, MONOLEPTA-AUSTRALIS (COL, CHRYSOMELIDAE), BY THE TACHINID, MONOLEPTOPHAGA-CALDWELLI (DIPT)

This paper examines the level and seasonal incidence of parasitism of the redshouldered leaf beetle, Monolepta australis (Jacoby), by the ta chinid, Monoleptophaga caldwelli Baranov, and assesses the impact of t his fly on the beetle's reproductive development and longevity. Highes t average numbers of M. australis were trapped at light in north Queen sland in January and February while parasitism peaked at 6.6 and 6.8 % in June and July respectively, averaging 4.8 % over the entire sampli ng period and reaching 28 % for a single occasion. Overall, only 2.4 % of parasitized beetles were represented in the final two stages of ov arian development compared to 29.1 % of non-parasitized ones. There wa s a highly significant (P < 0.001) difference in the distribution freq uencies of parasitized and non-parasitized females in the various stag es of ovarian development, and most parasitized males possessed atroph ied testes. For field-collected beetles maintained in the laboratory, average longevity for those parasitized was 15.6 days compared to 72.2 days for those not parasitized.