No abstract

An experiment was carried out to study the extinction and permanence of host-parasitoid systems with Allee effects, for both parasitism attacking before and after the growth phase of host. Allele effects and parasitism are common biological phenomena observed in nature. Allee effects and parasitism can lead to extinction of both species due to Allee effects at their low population density, multiple attractors, strange interior attractors and even crisis of strange attractor due to high parasitism. This study concentrated on Aphidius colemani an important and efficient endoparasitoid of several economically important aphid species under in-vitro conditions. The investigation studied its behavior and population change in relation to host and other environmental factors. Aphidius colemani discriminated between parasitized and unparasitized hosts. It is also suggested that this parasitoid performs best between 20 and 25°C and its population declines above or below this temperature.