NSF Project DEB-0841636 (Principal Investigator: P. H. Adler; Co-Principal Investigators: J.W. McCreadie, J. K. Moulton) Discovery and Prediction of Hidden Biodiversity in Black Flies (Diptera: Simuliidae)

Black flies (Simuliidae) are a worldwide group of more than 2,000 species of blood-feeding insects that breed in flowing water. They are structurally similar in appearance and many species, known as sibling species, defy distinction under the microscope. Roughly one-quarter of North America's species of simuliids have been discovered by detailed analyses of the giant, polytene chromosomes in the larval silk glands. Black flies are indicative of the extent to which additional biodiversity lies hidden in putative species of other groups of organisms. The overall objectives of the current project are to reveal all species, with particular attention to cryptic species, in the Simulium jenningsi species group, infer a phylogeny for understanding the evolution of biological traits, and develop a model to predict the probability of hidden biodiversity. To meet these objectives, an integrated, combinatorial approach is being used, incorporating cytogenetic, molecular, morphological, and ecological data. The Simulium jenningsi group is the model of choice because it 1) is the largest species group of black flies in the western hemisphere, 2) is widespread and abundant throughout eastern North America, 3) presents taxonomic problems that require integrated methodologies to resolve, and 4) is a high-profile group of insects among the public. The specific objectives and associated approaches are to 1) screen all 22 known species in the Simulium jenningsi group for additional, structurally similar or identical species, using cytogenetic analyses of polytene chromosomes, 2) use mitochondrial and nuclear genes to screen all nominal species for sibling species, 3) characterize all species morphologically, 4) provide multidimensional characterizations of niche breadth for all nominal species and use these characterizations as ecological probes for predicting hidden biodiversity, and 5) infer a phylogeny of the group, based on chromosomal, molecular, and morphological characters, which will illuminate the evolution of biological traits.

Intellectual Merit: A common goal shared by systematists, evolutionary biologists, and ecologists is to understand how biodiversity is generated and maintained. The synergy between ecology and systematics will be demonstrated by detecting and predicting the occurrence of sibling species embedded within morphologically defined species. Preliminary analyses have established a clear relation between the niche breadth of a morphotaxon and the presence of additional biodiversity (i.e., sibling species). Ecological traits, thus, have the ability to serve as powerful probes for the existence of biodiversity that otherwise might be missed; failure to resolve all species clouds biological interpretations and introduces a cascade of errors into an understanding of biological systems. Given the widespread existence of cryptic species, this methodology, with the Simuliidae as the model group, is broadly applicable to a broad range of taxa.

Broader Impacts: An integrated approach to understanding the complexity of life, although the most illuminating, is the most difficult for the individual biologist to master. Yet, a combinatorial approach represents the future of systematics. Expertise in morphology, cytogenetics, molecular systematics, and ecology, therefore, is being combined toward a common objective of understanding the biodiversity of the family Simuliidae. This expertise is being provided as an integrated package of skill sets to the next generation of biodiversity scientists, including high school, undergraduate, and graduate students. The continuing disappearance of systematists trained in morphotaxonomy and cytotaxonomy will be redressed by teaching the students to integrate these fields with current molecular and phylogenetic approaches; this goal is being accomplished through an integrated research program, team workshops, and day-to-day examples. The research promotes field and laboratory collaboration among an interdisciplinary team of faculty, high school students, undergraduate students, graduate students, and technical assistants at three institutions. The project also provides fundamental research essential to management of the Simulium jenningsi group.


Adler, P. H., R. A. Cheke & R. J. Post. 2010. Evolution, epidemiology, and population genetics of black flies (Diptera: Simuliidae). Journal of Molecular Epidemiology and Evolutionary Genetics of Infectious Diseases 10:846-865.
Link to online version. Opens new window.

McCreadie, J. W., P. H. Adler & C. E. Beard. 2011. Ecology of symbiotes of larval black flies (Diptera: Simuliidae): distribution, diversity, and scale. Environmental Entomology 40: 289-302.

Adler, P. H. & Y. T. Huang. 2011. Integrated systematics of the Simuliidae (Diptera): evolutionary relationships of the little-known Palearctic black fly Simulium acrotrichum. Canadian Entomologist 143:612-628.

Tang, X., P. H. Adler, H. Vogel & L. Ping. 2012. Gender-specific bacterial composition of black flies (Diptera: Simuliidae). FEMS Microbiology Ecology 80(3):659-670. Link to document

McCreadie, J. W. & P. H. Adler. 2012. The roles of abiotic factors, dispersal, and species interactions on structuring stream assemblages of larval black flies (Diptera: Simuliidae). Aquatic Biosystems 80:14.

Parks, K.S. 2013 (2011). Spontaneous triploidy in the black fly Simulium snowi Stone & Snoddy (Diptera: Simuliidae). Entomological News 122: 486-488.

Adler, P. H. & R. W. Crosskey. World blackflies (Diptera: Simuliidae): a comprehensive revision of the taxonomic and geographical inventory. 120 pp. Updated yearly.Published online

Adler, P. H., Y.-T. Huang, W. K. Reeves, S. K. Kim, Y. Otsuka & H. Takaoka. 2013. Macrogenomic evidence for the origin of the black fly Simulium suzukii (Diptera: Simuliidae) on Okinawa Island, Japan. PLOS ONE 8 (8): e70765. doi:10.1371/journal.pone.0070765