Colony founding in the primitively eusocial wasp, Ropalidia marginata (Hymenoptera: Vespidae)

Abstract

1. In a 16-month study in Bangalore, India, about 35% of the newly founded colonies of Ropalidia marginata were single foundress colonies and the remainder were multiple foundress colonies with two to twenty-two individuals. 2. Larger colonies did not have a significantly higher per capita productivity, did not produce significantly heavier progeny and did not produce them significantly faster than smaller colonies did. 3. Predation by the hornet Vespa tropica appeared to be independent of group size. 4. Single foundress colonies failed more often but not often enough to make them have a lower average per capita productivity, compared to multiple foundress colonies. 5. Some of the advantages of multiple foundress associations came from the greater predictability of their attaining the mean per capita productivity, the relatively lower rates of usurpation experienced by them compared to single foundress colonies, and the opportunities provided by queen turnovers for workers to become replacement queens and gain direct individual fitness.