I am interested in the origins and maintenance of insect diversity, with a focus on plant-feeding and parasitic insects. These organisms constitute the vast majority of animal species on Earth, but most tend to be small, relatively anonymous, and specialists on just one host species, and are therefore grossly understudied. I integrate traditional ecological experimentation with molecular genetic techniques and evolutionary theory to investigate the evolution of these charismatic but under-appreciated taxa.
In my lab, we have funding from the National Science Foundation (NSF) to explore speciation among a complex of Tephritid fruit flies (genus: Rhagoletis) and their associated parasitoid wasps (genera: Diachasma, Diachasmimorpha, Utetes and Coptera). Recent host shifts and incipient speciation events of the fly appear to be driving similar events in their parasitoids, leading to a veritable ‘starburst’ of recent speciation in this system. We are looking at how the ecologies, life histories, morphologies and genetic / genomic backgrounds of these insects both facilitate (and perhaps stymie) the genesis of new diversity.
Other ongoing projects in my lab include 1) Studies of speciation and hybridzation in sunflower maggot flies, 2) Consequences of human-mediated landscape modifications on diversity across multiple insect trophic levels, 3) Ecological and genetic studies of sexual vs. asexual wasp species, 4) Mathematical modeling of morphological preadaptations of parasitic wasps to their insect hosts, 5) Taxonomic and population genetic studies of ~20 species of parasitoids associated with leaf beetles in genus Neochlamisus.
Lab Website: http://www.biology.uiowa.edu/forbes.
Nelson AE, Forbes AA. 2014. Urban land use decouples plant-herbivore-parasitoid interactions at multiple spatial scales. PLOS ONE. 9(7):e102127.
Condon MA, Scheffer SJ, Lewis M Wharton RA, Adams DC, Forbes AA. 2014. Lethal interactions between parasites and prey increase niche diversity in a tropical community. Science 343: 1240-1244
Powell THQ, Forbes AA, Hood GR, Feder JL 2014. Ecological adaptation and reproductive isolation in sympatry: genetic and phenotypic evidence for native host races of Rhagoletis pomonella. Molecular Ecology. 23:688-704.
Forbes AA, Rice LA, Stewart NB, Yee WL, Neiman M. 2013. Niche differentiation and colonization of a novel environment by an asexual parasitic wasp. Journal of Evolutionary Biology. 26:1330-1340.
Forbes A.A. P.H. Kelly, K.A. Middleton, M. Condon. 2013. Genetically differentiated races and speciation-with-gene-flow in the sunflower maggot, Strauzia longipennis. Evolutionary Ecology. 27:1017-1032.
Forbes A.A., Satar S, Hamerlinck G, Nelson A.E., Smith J.J. 2012. DNA Barcodes and targeted sampling methods identify a new species and cryptic patterns of host specialization among North American Coptera (Hymenoptera: Diapriidae). The Annals of the Entomological Society of America. 105:608-612.
Feder JL, Egan SP, Forbes AA. 2012. Ecological Adaptation and Speciation: The Evolutionary Significance of Habitat Avoidance as a Postzygotic Reproductive Barrier to Gene Flow. International Journal of Ecology. 2012: 15 pages.
Forbes, A.A., G. R. Hood and J. L. Feder. 2010. Geographic and ecological overlap of parasitoid wasps associated with the Rhagoletis pomonella (Diptera: Tephritidae) species complex. The Annals of the Entomological Society of America. 103:908-915.
Forbes, A.A., K.S. Pelz-Stelinski, and R. Isaacs. 2010. Transfer of life history phenology from mothers to progeny in a solitary univoltine parasitoid. Physiological Entomology. 35:192-195.
Feder, J.L. and A.A. Forbes. 2010. Sequential speciation and the diversity of parasitic insects. Ecological Entomology. 35:67-76.
Forbes, A.A., L.L. Stelinski, T.H.Q. Powell, J.J. Smith and J.L. Feder. 2009. Sequential sympatric speciation across trophic levels. Science 323: 776-779.
Feder, J.L. and A.A. Forbes. 2007. Habitat avoidance and speciation for phytophagous specialists. Functional Ecology 21:585-597.
Xie, X., J. Rull, A. Michel, S. Velez, A.A. Forbes, N.F. Lobo, M. Aluja and J. L. Feder. 2007. Hawthorn-infesting populations of Rhagoletis pomonella and speciation mode plurality. Evolution 61:1091-1105.
Forbes, A.A. and J.L. Feder. 2006. Divergent preferences of Rhagoletis host races for olfactory and visual fruit cues. Entomologia Experimentalis et Applicata 119:121-127.
Forbes, A.A., J. Fisher and J.L. Feder. 2005. Habitat avoidance: overlooking an important aspect of host specific mating and sympatric speciation? Evolution 59: 1552-1559.