Natal habitat conditions have carryover effects on dispersal capacity and behavior

Abstract

Local habitat quality affects regional dynamics, including metapopulation persistence and speciation, by altering dispersal. However, most previous studies have not been able to determine whether dispersal is more strongly affected by habitat quality experienced at the dispersal stage, or carryover effects of habitat quality from previous life stages. Strong carryover effects will cause dispersal to be temporally disconnected from its drivers, altering the impact of dispersal on metapopulation dynamics, and potentially complicating empirical estimates of context-dependent dispersal. Here, we used a fully factorial mesocosm experiment to assess how both habitat quality experienced during development and at adulthood affected emigration in adult backswimmers (Notonecta undulata). We found strong carryover effects of natal habitat quality on dispersal; individuals from high-quality natal environments had higher emigration rates than individuals from low-quality natal environments. However, emigration did not depend on adult habitat quality. This suggests that conditions experienced during development can outweigh the effects of habitat quality at later life stages, resulting in time lags between environmental triggers and the onset of dispersal behavior. If there are critical life stages at which dispersal rates are determined, habitat quality at those stages may have outsized impacts on biological dynamics in spatiotemporally variable landscapes.