Influence of historical land use and modern agricultural expansion on the spatial and ecological divergence of sugarcane borer, Diatraea saccharalis (Lepidoptera: Crambidae) in Brazil

Human-mediated changes in landscapes can facilitate niche expansion and accelerate the adaptation of insect species. The interaction between the evolutionary history of the sugarcane borer, Diatraea saccharalis Fabricius, and historical and modern agricultural activity in Brazil shaped its spatial genetic structure, facilitating ecological divergence and incipient host-shifting. Based on microsatellite data, STRUCTURE analyses identified two (K=2) and three (K=3) significant genetic clusters that corresponded to: a) a strong signal of spatial genetic structure and, b) a cryptic signal of host differentiation. We inferred that K=2 reflects the footprint of agricultural activity, such as expansion of crop production (sugarcane and maize), unintentional dispersion of pests, and management practices. In contrast, K=3 indicated incipient host differentiation between larvae collected from sugarcane or maize. Our estimates of population size changes indicated that a
historical bottleneck was ...