Kin competition promotes dispersal in a male pollinating fig wasp

Abstract

Despite theoretical predictions, there is little empirical evidence that kin competition avoidance promotes dispersal. We show that dispersal by male Platyscapa awekei pollinating fig wasps is promoted by both low returns in the natal fig and kin competition avoidance, with strategies depending on the interaction between phenotype (body size) and local conditions. We discuss the paucity of similar work, how males might assess conditions, and then contrast male dispersal and fighting behaviour. This indicates that differences in the scale at which behaviours affect competition can mean that they are the product of dissimilar selective forces even when they have the same recipients. More generally, this could explain why other social interactions are often mixtures of cooperation and conflict.

Figure 1

Relationships between female number and predicted dispersal probability in: (a) single-foundress and (b) two-foundress figs. Thick lines represent predictions when male number is low (=6), thin lines predictions when male number is high (=12). Solid lines represent predictions for small males (tibia length³=0.004 mm³), dotted lines predictions for large males (tibia length³=0.012 mm³).