Genetic differentiation associated with host plants and geography among six widespread lineages of South American Blepharoneura fruit flies (Tephritidae)

Authors: OTTENS, KRISTINA - University Of Iowa; WINKLER, ISAAC - Cornell College - Iowa; Lewis, Matthew; Scheffer, Sonja; GOMES-COSTA, GESSICA - Universidade De Pernambuco; DE V. BARBOSA, MARIA - Universidade Federal Da Paraiba (UFPB); CONDON, MARTY - Cornell College - Iowa; FORBES, ANDREW - University Of Iowa

Submitted to: Journal of Evolutionary Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/13/2017
Publication Date: 4/5/2017
Citation: Ottens, K., Winkler, I.S., Lewis, M.L., Scheffer, S.J., Gomes-Costa, G.A., De V. Barbosa, M.R., Condon, M.A., Forbes, A.A. 2017. Genetic differentiation associated with host plants and geography among six widespread lineages of South American Blepharoneura fruit flies (Tephritidae). Journal of Evolutionary Biology. 30:696-710.

Interpretive Summary: True fruit flies such as the medfly cause millions of dollars of economic losses to US and global vegetable and fruit production. We investigated patterns of genetic variation in host plant use in populations of Blepharoneura fruit flies feeding on flowers of several plants in the melon family. We found that genetic differences as well as host-use often evolve between populations of flies in different locations rather than via cryptic speciation in a single location. This implies, in general, that the same species of fruit fly from different locations may be substantially different and require population-specific pest management strategies. This research will be of interest to scientists involved with pest management, ecology, and evolutionary biology.

Technical Abstract: Tropical herbivorous insects are astonishingly diverse and many are highly host-specific. Much evidence suggests that herbivorous insect diversity is a function of host-plant diversity; yet, the diversity of some lineages exceeds the diversity of plants. Although most lineages of herbivorous fruit flies in the Neotropical genus Blepharoneura are highly host-specific (specific to single host plant species, plant tissue, and often flower sex), some lineages include individuals reared from other hosts. We investigate patterns of diversification within several widespread lineages of Blepharoneura that include individuals reared from different hosts. We use microsatellites to: 1) test for evidence of local genetic differentiation associated with different sympatric hosts (different species or sexes of plants); and 2) examine geographic patterns of genetic differentiation across multiple South American collection sites. We target six previously identified lineages that are geographically widespread and that have been collected and reared from at least two host-plant species or host-plant parts. In four of the six fly lineages, we find evidence of local genetic differences between sets of individual flies reared from different hosts. All six lineages show evidence of geographic structure, with consistent differences between flies collected in the Guianan Shield and flies collected in Amazonia. Continent-wide analyses reveal - in all but one instance - that genetically differentiated flies reared in sympatry from different hosts are not one another’s closest relatives, indicating that genetic differences often arise in allopatry before, or at least coincident with, the evolution of novel host use.