Agenda

Nitika Sharma, Centre for Ecological Sciences, Indian Institute of Science, Bangalore, India

Titolo: Do individuals show any spatial organization on the nest of the primitively eusocial wasp Ropalidia marginata?

Abstract:
Ropalidia marginata is a primitively eusocial paper wasp species widely distributed in peninsular India. Particularly for social insects, nests remain elemental locations of social interactions and division of intra-nidal tasks. Thus, exploring the spatial organization of these paper wasps could potentially shed light on the dynamics of reproductive as well as non- reproductive division of labor. We video recorded each nest for 10 hours each day for 3 consecutive days and extracted the spatial location of each nestmate every 6th minute. We plotted fifty percent kernel density maps (core areas) for each wasp on a nest to check if they showed a non- random “spatial fidelity”. Approximately 50% wasps on each nest showed spatial fidelity. The queen showed spatial fidelity more often than the workers. Our preliminary results also indicate that more subordinate individuals occupied larger areas in the nest as compared to dominants. Unlike typical primitively eusocial species, the R. ma rginata queen is docile (non- aggressive) and is believed to rub her pheromones on the nest surface to maintain reproductive monopoly. In the absence of a well-functioning queen, only one worker- called the potential queen (PQ) becomes hyper-aggressive, remains unchallenged by the rest and goes on to become the new queen. We also plan to explore if the PQ physically avoids overlap with the queen on the nest to escape her pheromones. Since the brood in these nests are not clumped and are distributed across the surface of the nest, we are also interested in studying the mechanism of food distribution to different stages and locations of brood by the workers.