Adult Emergence Interval and Reproduction in Parasitic Hymenoptera Influenced by Host Size and Density1

Abstract

The following is based largely on the authors' abstract. Extensive collections of ectophagous parasites of synanthropic flies from accumulations of animal faeces in the United States, Mexico, Costa Rica, Puerto Rico, Uruguay, Chile, Denmark, Israel and South Africa yielded seven forms of a Muscidifurax complex that were wholly or partly isolated reproductively [cf. RAE B 57 1016]. Morphological studies of adults of both sexes, combined with biological and zoogeographical information, made possible the separation of five sibling species. In this paper, M. raptor Gir. & Sand., which is recognised from the United States, Israel and Denmark, is redescribed, and four species are described as new. These are M. zaraptor sp. n. from the south-western United States, M. raptoroides sp. n. from Costa Rica and Mexico, M. uniraptor sp. n. from Puerto Rico [cf. 56 375] and M. raptorellus sp. n. from Uruguay and Chile. Biological notes on each are included, and a key to the adults of the five species, including morphological and zoogeographical and biological differences, is given. The genus is apparently undergoing a process of speciation with local populations slowly becoming reproductively isolated and eventually giving rise to morphologically distinguishable entities. The evidence suggests that Muscidifurax is an element of the Ethiopian fauna that became established in the New World at the same time as Musca domestica L. [cf. 55 670] or shortly after.