Suppression of reproductive development and longevity in the redshouldered leaf beetle, Monolepta australis (Col.: Chrysomelidae) , by the tachinid, Monoleptophaga caldwelli (Dipt.)
Fay, HAC.; Storey, RI.; Defaveri, SG.; Brown, JD.
Entomophaga 38(3): 335-342
1994
ISSN/ISBN: 0013-8959
Accession: 021833731
This paper examines the level and seasonal incidence of parasitism of the redshouldered leaf beetle,Monolepta australis (Jacoby), by the tachinid,Monoleptophaga caldwelli Baranov, and assesses the impact of this fly on the beetle's reproductive development and longevity. Highest average numbers ofM. australis were trapped at light in north Queensland in January and February while parasitism peaked at 6.6 and 6.8% in June and July respectively, averaging 4.8% over the entire sampling period and reaching 28% for a single occasion. Overall, only 2.4% of parasitized beetles were represented in the final two stages of ovarian development compared to 29.1% of non-parasitized ones. There was a highly significant (P<0.001) difference in the distribution frequencies of parasitized and non-parasitized females in the various stages of ovarian development, and most parasitized males possessed atrophied 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.