Abai, MR

6th International Congress of DipterologyBloodsucking pollinators converge: evidence for localadaptation from the first molecular phylogeny of horse flies(Diptera: Tabanidae).Morita, S. I.Population Biology Graduate Group, University of California at Davis, California, 95616,USA.Horse-flies (Diptera: Tabanidae) are both vectors of disease and importantpollinators. Pangoniinae, especially Philoliche (Wiedemann), often haveextremely long-proboscides specialized for nectar-feeding. The P.aethiopica (Thunberg) species complex in South Africa is known for itstaxonomic confusion with extreme variation in proboscis lengths whichmay be due to adaptation to floral resources. It historically includes twospecies, P. aethiopica and P. rondani (Bertoloni). Based on this, I addressthe following questions: 1) What are the phylogenetic relationships withinthe Philoliche aethiopica species complex? 2) Is long-proboscis (LT)morphology derived in Philoliche? 3) Has LT morphology evolvedmultiple times? 4) Is there a trend in proboscis length evolution? Iproduced a phylogeny from the nuclear gene CAD and the mitochondrialgene COI by sampling species from 8 of 9 tribes in all three subfamilies inTabanidae to produce a fossil calibrated chronogram in the program r8s.The molecular data combined with a new morphological character andbiogeography support 6 lineages in the P. aethiopica species complex. P.aethiopica and P. rondani are mutually exclusive, but both have long andshort proboscid lineages. The LT taxa both occur in the Albany Center ofendemism. Reconstruction of ancestral character states using weightedsquared change parsimony shows that LT morphology is derived inPhiloliche and supports convergence for long proboscides in the AlbanyCenter between P. aethiopica and P. rondani. Proboscis length was alsoanalyzed as a discrete character using Maximum Likelihood. A model ofincreasing proboscis length evolution over evolutionary time under a tworate model is significantly more likely than a one without a trend inproboscis length (one rate model) based on a log likelihood ration test.170