Mate choice patterns based on the age of males/females: a laboratory study of the primitively eusocial wasp Ropalidia marginata
Student name: Ms Gunjan Jindal
Guide: Dr Sudipta Chatterjee
Year of completion: 2017
Host Organisation: Indian Institute of Science, Bangalore
Supervisor (Host Organisation): Prof Raghavendra Gadagkar
Abstract: The effect of age of males and females on mate selection was investigated through choice based assay
in the primitively eusocial wasp Ropalidia marginata. In this study, we offered a choice of two virgin
partners of different age groups of 5-10 and 15-20 days old respectively to a virgin test male or to a
virgin test female of age group 5-20 days old, since it is known from previous study that individuals of
Ropalidia marginata are reproductively active in the mating range of 5-20 days. We measured the
probability that the test individual would mate with any particular partner based on the age. Our study
shows that even when a choice is available to the males in male mate choice experiments, they do not
discriminate the females based on the age of the females and mate randomly. Males live a nomadic life
and have no such investment in bringing up of the offspring and thus making a mate choice based on
the age of the females is not crucial for him. On the other hand, females preferred to mate with older
males when given a choice in female mate choice experiments. Older males are probably of higher
genetic quality and might provide superior genes to their offspring, thus providing direct fitness
benefits. In Ropalidia marginata, female parental investment exceeds male parental investment in
terms of brood development and colony maintenance, hence making a choice is costlier for females as
compared to males.
Key words: Male mate choice, female mate choice, Ropalidia marginata, mate selection, parental
investment
