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Studies on some aspects of reproduction and behaviour of an arrhenotokous eulophid Melittobia acasta Walker

<U>Melittobia acasta </U>Walker is a parasitoid of many insect species distributed in several families among which is the Calliphorinae. In this study, its reproductive behaviour and interactions with one of its hosts, <U>Calliphora</U> species puparia, were examined. The courtship behaviour pattern of <U>M. acasta</U>, which is innate, is described. Unlike other parasitoids, such as <U>Nasonia vitripennis</U> Walker, copulation occurs within the host puparium before emergence. The females in this species are more active that the males and assume the role of chasing males during mate location. Although the males are mutually antagonistic, fighting on making contact with each other, they do not decapitate the loser in fight as previously described by many workers. Where several females are present within a puparium, males ignore each other, preferring mating activity. Host finding is random. After finding a puparium, the female taps it on the outside with the antennae and abdomen, then decides whether the pupa inside is acceptable for oviposition. If it is, the female drills into the puparium with the ovipositor, probes the host and then lays eggs on the pupa within the puparium. Two types of drilling were noticed; drilling for food and drilling for egg laying. Most of the drillings were at the intersegmental notches of the puparium. <U>Calliphora</U> sp. puparial age and size had a significant effect on the parasitoid's clutch size and sex ratio but no effect on the development time, order of male/female egg laying and size of parasitoids emerging from the puparium. The ovipositing females preferred living, envenomed, non-diapausing puparia to dead, unvenomed or diapausing ones. The sense organs on the antennae and ovipositor that aid the parasitoid in assessing and utilising <U>Calliphora</U> sp. puparia are described.

Identiferoai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:637368
Date January 1999
CreatorsImandeh, G. N.
PublisherSwansea University
Source SetsEthos UK
Detected LanguageEnglish
TypeElectronic Thesis or Dissertation

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