Individuals often vary in their propensity to disperse as well as in how far they travel during dispersal. Traits that shape individual differences in dispersal behavior may also affect the impact individuals have on the patches they colonize. In order to assess how individual variation in dispersal behavior shapes the distribution of phenotypes across space, we addressed the question: do individuals laid across a gradient of patch isolation differ behaviorally? Larval dragonflies are important predators in freshwater systems and so we focused on a behavioral trait likely to have impacts throughout the food web – foraging rate. To test for a correlation between the isolation of the natal habitat patch and larval foraging rate, we established standardized habitat patches (artificial pools) across a landscape at varying distances from potential source habitats. These pools were naturally colonized by dragonfly larvae. After larvae were collected from pools they were held under common lab conditions for five months, approximately half the larval life-span, before comparing larval foraging rates.
Results/Conclusions
Larval foraging rate was positively related to the level of habitat isolation of the natal pool. Larvae that were collected from the most isolated pools had significantly higher foraging rates than individuals collected from the least isolated pools. Our results indicate that spatial patterns in colonist behavior can develop across a landscape independent of species-level dispersal limitation. This finding has implications for the structure of communities and food-webs across varying levels of isolation. These results suggest that the strength of species interactions within habitats may vary spatially because of correlations between individual dispersal behavior and other behavioral traits. Our results also suggest that studies investigating the effects of dispersal limitation should include an assessment of the distribution of phenotypes as well as species-level dispersal limitation patterns.
