Meeting Abstract
Spatial sorting describes a mechanisms of evolutionary change where differential dispersal ability spatially structures mate choice, leading to rapid evolution favoring increased future dispersal capacity along an expanding range edge. We test the role of spatial sorting in the red-shouldered bug (Jadera haematoloma) as they recolonize areas that went locally extinct. These seed feeding insects are a model system for rapid ecological adaptation, as their beak lengths have been shown to quickly evolve to match the seedpod physiology of their different host plant associations. In addition, these insects express a discrete wing polymorphism that renders a proportion of the population flightless. These two traits are associated, in that, flighted individuals have longer beaks than their flightless counterparts. Serendipitously, this trait association creates both a differential in dispersal ability to fulfill the requirement of spatial sorting, and an ecologically relevant trait which we can observe in the face of natural selection. Through continuous monitoring of these traits before and after local extinction due to a catastrophic weather event, we test spatial sorting’s evolutionary capacity as locally extinct metapopulations are re-colonized. Our study shows that flighted individuals are capable of recolonizing extinct patches, and that these re-colonizers bring with them longer beaks than the previous inhabitants. These longer beaks not only persist over multiple generations but also tend to grow longer as mate choice in recolonized patches remains limited to only long beaked flighted individuals. Interestingly, this increase in beak length occurs in habitats where it is adaptive and maladaptive, demonstrating that spatial sorting is a powerful evolutionary mechanism that can promote rapid morphological change.
