Meeting Abstract
Geometric morphometric analysis of wing shape can reveal morphological differentiation between insect populations, yet it remains unclear if such differentiation is due to genetic drift, or is an adaptive response to local environments. Environmental gradients often result in morphological differentiation among populations, and wing shape differs significantly among lineages of a widely distributed Mesoamerican species complex of bumble bees (Bombus ephippiatus sensu lato) which inhabit variable climates from 515m to 3555m above sea level. Comparative analysis of wing shape among populations of bumble bees found across similarly broad altitudinal gradients at a range of latitudes in the western United States (B. vosnesenskii and B. bifarius) could provide new insights into widespread patterns of wing shape evolution in response to climate. Variation in environmental temperature across latitude and altitude can strongly influence wing size and shape, and reduced air density at high altitude may further constrain wing shape to maintain force production. We used a landmark approach to characterize wing shape of ~1200 bumblebees collected from 14 to 47°N latitude and from 49 to 3555 m asl. We discuss patterns of wing shape divergence congruent with altitudinal distribution as well as population structure. For instance, within Mexico two sympatric lineages occurring at interrupted altitude zones (~500m apart) show the greatest disparity in wing shape second only to two lineages occurring on opposite ends of the country (~2000 km apart over 10° latitude). Determination of the relative effects of phylogeny and local environment on wing shape across broad geographic scales provides insights into the evolution of insect flight morphology.
