Maddison and Ober The diversity of many groups of living organisms is related to the evolution of novel features that contribute to an explosive increase in the number of species. Adaptations acquired during such a radiation posses specialized functions and a unique evolutionary history. An example of increasing diversification of species and progressive specialization can be found in carabid beetles, commonly known as ground beetles, that have adapted an arboreal lifestyle. Graduate student Karen Ober, under the direction of Dr. David Maddison, is studying the evolution of arboreal adaptations in carabid beetles by surveying representative taxa across the 10 or so tribes of the large group Lebiomorpha. New collections from Malaysia and from Madagascar (the latter supplied by colleagues) will augment museum holdings and provide materials for molecular and morphological studies. Morphological features include tarsal and claw structures (independent of those associated with mating), leg length, and prorhorax shape, which may be involved in adaptive changes to arboreal life. To investigate the origin and evolution of arboreal carabids, an evolutionary tree of lebiomorphs and their relatives will be reconstructed using molecular sequence data from minimally two genes, the 28S ribosomal RNA gene and the nuclear gene 'wingless.' Both show promise of providing mutational differences that would allow discrimination among lineages of lebiomorphs. With the evolutionary history of relationships in hand, one can study the number and direction of habitat shifts from ground-dwelling to arboreality and explore patterns of changes in ecological and morphological features presumed to be associated with arboreal life.
