Background/Question/Methods Our study aims to understand the patterns of sexual variation between Nasonia species. To quantify such variations underlying intraspecific and interspecific differences, estimating quantitative behavioural parameters of the trait is essential. Parasitoid Nasonia is a group of four closely related species, used as a model for evolutionary and developmental genetics. The major question of our study is to look for the parameters based on which a female selects a male (mating partner). First, we compared the courtship behaviour of the four sibling species. We recorded both intraspecific and interspecific courtship behaviour under Leica (dissection light microscope) keeping temperature, light and the age of wasp constant. The courtship behaviour of Nasonia males includes mounting on females, orientation on female's head, repeated series of stereotypic movements including cyclic head-nod series, mouth extrusions, antennal sweeps, wing vibration (Pre-copulatory phase). Female signals receptivity by lowering down their antennae in synchrony with the opening of the genital orifice (copulatory phase), after copulation males engage themselves in a unique post-copulatory phase. Secondly, we looked on to the level of hetero-specific male acceptance after transferring the male extracts of one species male to another species using Dichloromethane (a low volatile chemical). Results/Conclusions All the recorded videos were analyzed with parametric statistics (one way ANOVA, Tukey HSD) using R software along with Bonferroni Correction. Although the species are morphologically similar, yet there are distinct differences in the length of courtship cycles, the number of head-nods, antennal sweeps, wing fluttering and their orientation during courtship. Our study shows that closely related species can often be distinguished based on the level of hetero-specific male acceptance. Hetero-specific male acceptance changes with the transfer of male extract (using Dichloromethane) from one species male to another species male. Male extract transfer experiment significantly changes the level of mate acceptance among the most ancient (Nasonia vitripennis) and most recent (Nasonia oneida) species of Nasonia. Although we did not find any significant changes by the same experiment among the two other species (Nasonia longicornis and Nasonia giraulti). From our experiments, we can conclude that in the case of Nasonia vitripennis and Nasonia oneida, females select their mates using male extract as a parameter, which is not true for the other two species. We are trying to find out the possible parameters which are preferred by Nasonia longicornis and Nasonia giraulti females during mate selection.
