Rapid evolution of reduced receptivity to interspecific mating in the dengue vector Aedes aegypti in response to satyrization by invasive Aedes albopictus

Abstract

In this paper we examine the effect of reproductive interference on the dynamics of two mosquito vectors of public health concern and add to the growing literature on the strength and speed with which interspecific reproductive interference may drive evolution. Recent evidence supports a role for asymmetric reproductive interference, or satyrization, in competitive displacements of Aedes aegypti by Aedes albopictus. However, populations of A. aegypti sympatric with A. albopictus in nature evolve resistance to satyrization. Here we report that A. aegypti from Tucson, Arizona (USA), where A. albopictus are not known to occur, are satyrization-susceptible. Furthermore, in cage experiments we demonstrate rapid evolution in satyrization-susceptible lines. Exposing allopatric strains of A. aegypti to A. albopictus in cages led to significant reductions, within 1-3 generations, in the frequency of reproductive interference. We also demonstrate that satyrization-resistant A. aegypti females derived from selection experiments are significantly slower to mate with conspecific males, suggesting a cost for the evolution of satyrization-resistance. Results show how interspecific interactions between these vector species are rapidly evolving, with implications for the arboviral diseases, especially dengue and chikungunya, which they transmit.

Keywords: Aedes; interspecific mating; rapid evolution; satyrization.

Figure 1

Evolution of resistance in A. aegypti females to satyrization by A. albopictus males. Solid lines show selected KW (a), Miami (b) and Tucson (c) strains, while dashed lines present controls from the same locations that were not exposed to A. albopictus.