Three better than two but two not better than one: A study of nest foundation in the primitively eusocial wasp Ropalidia marginata (#893)
In primitively eusocial wasp Ropalidia marginata, new nests can be initiated by a single female or by a small group of females. To study the effect of number of foundresses on rate of nest growth and productivity, we removed female wasps from their nests, on the day of their eclosion and maintained them in isolation, in pairs or in triplets; those kept in pairs and triplets were nestmates. The wasps were provided with ad libitum food, water and building material to start new nests. We found that both the rate of nest growth and nest productivity did not differ between nests founded by one and two wasps. However, nests founded by three wasps had significantly higher rates of nest growth and greater nest productivity compared to those of both single and paired wasps. We hypothesize that with two wasps, cooperation balances conflict so that there is not much change in the rate of nest growth and productivity compared to a solitary wasp. With three wasps however, the third wasp who has the least chance of reproduction, will show more cooperation and less conflict, resulting in higher rate of nest growth and productivity compared to nests founded by one or two wasps. These hypotheses are being tested by behavioural observations.