EFFECTS OF SCHEDULED HIGH TEMPERATURE ON MALE PRODUCTION IN THELYTOKOUS MUSCIDIFURAX UNIRAPTOR (HYMENOPTERA: PTEROMALIDAE)

Abstract

AbstractThe production of excess males in thelytokous Muscidifurax uniraptor Kogan & Legner was triggered by high temperature (32.2 °C) during oviposition, and may result from a blockage of endomitosis in the egg. A minimum oviposition period of 24 h at 25 °C prior to continuous high temperature was an important prerequisite. A few receptive oocytes may be present before oviposition, with new ones formed during the first 24 h of the oviposition period at 25 °C. Although heat treatment must begin during a relatively short receptive period ("window of susceptibility") early in adult life, it has to persist longer than 24 h at low oviposition rates (20 hosts/day) and < 24 h at high oviposition rates (50 hosts/day) to block effectively endomitosis and the formation of diploid, female-producing eggs.