The Incidence of Parasitized Pupa Detection by Nasonia Males

Abstract

For a Nasonia male, emerging first from the host puparium and staying in the vicinity of it ensures and increases the possibility of meeting and eventually courting and mating either with its sisters or females from adjacent pupa. Nasonia males survive for 2-3 days only (P. E. King and C. R. Hopkins, 1963) and hence, are under a considerable selection pressure to mate with as many females as possible whereas female mates only once. It is advantageous for a male to detect unborn virgin females, inside a patch of available hosts (parasitized and unparasitized). Hence, it becomes a necessity for Nasonia males to discriminate between a parasitized and unparasitized pupa, to receive potential mates. The present study investigates the sex of first emerging individuals in Nasonia and whether Nasonia males can detect parasitized pupa. N. vitripennis males emerge as the first individual in most of the pupa but for its sibling species N. giraulti and N. longicornis, male and female as well can be the first emerging individual. Due to higher proportion of within host mating in N. giraulti and N. longicornis sex ratio is more female biased as compared to N. vitripennis. In N. vitripennis 65% females were present in the average family size of 26 individuals (N=30) whereas in N. giraulti 87.5% and N. longicornis 85% females were present in the average family size of 24 (N=27) and 26 (N=35) respectively. We found that Nasonia males can detect parasitized pupa from unparasitized pupa.