Do individuals of the primitively eusocial paper wasp Ropalidia marginata show non-random spatial organization on the nest?
NITIKA SHARMA, Nitika Sharma , Raghavendra Gadagkar
INDIAN INSTITUTE OF SCIENCE, BENGALURU, INDIA; Indian Institute of Science, Bengaluru, India ; Indian Institute of Science, Bengaluru, India
Animals often use space within their home ranges non-randomly with concentrated use around food, mates or refuges. Whether social insects similarly use space on their nests non-randomly has not been investigated adequately. We studied how wasps use space on the nests of the primitively eusocial paper wasp Ropalidia marginata, using 30 hours of observation on each of six nests, providing behavioural and spatial information for a total of 155 wasps. We considered a wasp to show spatial fidelity when it was sighted in its high density area (core area) more often than expected by chance alone. On average, 62.4% ± 16.2% wasps showed spatial fidelity and the probability of showing spatial fidelity was more for wasps that spent more time sitting and grooming themselves and less for those that received high levels of aggression. Of the wasps that showed fidelity those that fed larvae often and those that received aggression often held larger core areas. Measured both by the extent of overlap of core areas of queens and workers and by the Euclidean distance between them, we found that the potential queens were usually neither the closest nor the farthest from the queens. We also found that wasps which fed larvae and those that received more aggression were closer to the centre of worker distribution while those that foraged more often occupied locations at the periphery. Studying such spatial organization of the wasps on their nest can potentially help understand the mechanisms by which reproductive and non-reproductive division of labour are achieved.