Response to Akcali et al.: What keeps them from mingling.

12 Jun 2018

The salt marsh beetle Pogonus chalceus has diverged into short- and long-winged populations, which can be found in hundreds of interlaced habitat patches that sharply differ in their hydrological regime. In a recent study, we investigated how a behavioral adaptation to these contrasting hydrological regimes might drive the neat spatial sorting of the ecotypes and facilitate divergence. Simulated inundation experiments revealed that the ecotypes differ in dispersal response toward the hydrological regime and that this is a plastic behavior imprinted during the nondispersive immature stages. In their comment, Akcali and Porter (2017) question if the observed plastic response would effectively reduce gene-flow in this system. Based on the natural history of this species we demonstrate why this is plausible and we propose future avenues that may further strengthen this conclusion. In addition, Akcali and Porter (2017) illustrate some current inconsistencies in the use of terminology of the different habitat choice mechanisms. We agree that proper classification of the existing theories is indispensable in advancing the field of habitat choice mechanisms and their effect on gene flow, but the unique attributes of any given biological system may thwart this exercise.