ASPECTS OF BIOLOGY OF Acerophagus papayae Noyes & Schauff (HYMENOPTERA: ENCYRTIDAE), PARASITOID OF THE PAPAYA MEALYBUG

Abstract

Aspects of biology of Acerophagus papayae Noyes & Schauff (Hymenoptera: Encyrtidae), parasitoid of papaya mealybug. Acerophagus papayae Noyes & Schauff (Hymenoptera: Encyrtidae) is an important parasitoid of the papaya mealybug, Paracoccus marginatus Williams & Granara de Willink (Hemiptera: Pseudococcidae). The study was conducted with the objective to determine various aspects of the biology of A. papayae which include the effect of diet on adult longevity, fecundity and progeny, host stage susceptibility and preference, the effect of host stages on immature development, body size, and sex ratio of progenies.  Effects of diet on adult longevity was done in the absence of hosts. Fecundity was measured by the number of mealybugs parasitized. Host stage susceptibility and preference were carried out by exposing 2^nd  and 3^rd  nymphal instars and pre-reproductive adults of mealybugs to parasitoids. Results showed adult parasitoids fed with 10% honey solution lived almost fourfold longer than those provided only water. A. papayae parasitized 30.1±4.92 mealybugs, with a range of 13-60 mealybugs, during 5.8 days of adult life.  In no-choice (susceptibility) and paired-choice (preference) tests, the percentage of parasitized hosts were significantly greater in 2^nd and 3^rd instar nymphs than in adults. The mean immature developmental time of A. papayae was longer when the parasitoids develop in large host. Developmental time of male parasitoids was shorter than the females. Female wasps which emerged from hosts parasitized at the 3^rd instar nymphs and adults were significantly larger than those from the 2^nd instar nymphs.  Sex ratios of the offspring emerged from hosts that were parasitized as 2^nd instars were strongly male-biased, while the later stages yielded more females than males.