Sensory niche partitioning in two sympatric social wasps: sugar responsiveness could determine foraging patterns in yellowjackets

Abstract

Sympatric-related species often exhibit resource partitioning. This can occur through different mechanisms, such as behavioral, morphological, and sensory variations, leading to qualitative, temporal, or spatial differences in resource exploitation. Sensory-based niche partitioning could be the underlying mechanism through which closely-related species effectively reduce niche overlap. Here we ask whether variations in sensory responses to carbohydrates could reflect differences in the foraging patterns of two Vespula sp. species present in Patagonia. We established (i) the response thresholds toward carbohydrate solutions of foraging V. germanica and V. vulgaris in the laboratory, (ii) the sugar concentration of carbohydrates foraged in the field, and (iii) effect of incoming sugar concentration on individual and colony performance. Results indicate a higher sucrose response threshold in V. germanica than V. vulgaris, with higher carbohydrate concentrations foraged by V. germanica (57% of V. germanica foragers returned with concentrations above 50 Brix, while 23% of V. vulgaris foragers did so). Differences in sensitivity and foraging, positively correlate with colony size, suggesting that competition could be reduced in these closely-related invasive social wasps through sensorial differences in their sugar perception levels. This is the first study to suggest that sensorial niche partitioning could promote species coexistence in social wasps.