Food stress during juvenile and maternal development shapes natal and breeding dispersal in a spider

Abstract

Dispersal is affected by a broad array of environmental conditions, including those experienced by parents. This enables offspring to combine parental habitat cues with information on the current environmental conditions in determining dispersal strategies. Despite the potential importance of such parental effects on both the timing of dispersal and the dispersal distance, empirical evidence for either remains scarce. We tested the strength of maternal effects on dispersal in the dwarf spider Erigone dentipalpis, establishing specifically, the influence of food supply across 2 generations on dispersal propensity in juveniles and adults. The latter perform either short-distance (rappelling) or long-distance (ballooning) dispersal. Direct, but not maternal, starvation negatively affected fitness-related life-history traits in offspring, and only starved juveniles emigrated toward new habitat. Adult rappelling decreased in food-deprived males, indicating an asymmetry in sex-related costs of short-distance dispersal. In contrast, the propensity of ballooning was determined by the interplay between maternal and direct feeding regimes: sustained high levels of food availability across generations decreased ballooning, whereas starvation of the mother or during the juvenile stage induced intermediate ballooning responses relative to conditions in which both mothers and offspring were starved. Our findings thus demonstrate the presence of different evolutionary mechanisms behind long- and short-distance dispersal strategies and importantly highlight the role of maternal effects in the dynamics of spatially structured populations.