Paul Frandsen and Dr. C. Riley Nelson, Biology
Dance flies from the super family Empidoidea (Diptera:Empididae, Hybotidae) were collected from western Mongolia in June and July 2009. Historical published records of Empididae in Mongolia along with unpublished, more recently collected records from the Selenge River Basin were compared with the samples from western Mongolia. Thirteen genera were identified from western Mongolia in 2009, with eight of these new for the country. Although 23 genera are now know for Empedoidea in Mongolia, only five were found in both the Selenge River and the 2009 collection from western Mongolia, suggesting distinct differences in faunal composition between the two areas.
Mongolia is a large country between Russia and China. The country is 1,564,116 square-kilometers, about one-fifth the size of the continental United States. The population is 2.9 million people making it the most sparsely populated independent country in the world (United Nations 2008). Much of the land in Mongolia is inhabited by nomadic peoples whose primary use of the land is for animal grazing purposes. It is a country that has historically been under strong Soviet influence, but in the past 16 years it has begun the process of democratization. With democratization, transformation to a capitalistic economy and potential privatization of land, the country’s natural resources could be at risk. Therefore a survey of animals is important in order to make knowledgeable decisions in its conservation (Wilson 2000).
Dance flies (Diptera: Empididae, Hybotidae) are very diverse families of flies. There are about 4,000 known species in the world (Yang 2008). When these insects swarm together they fly up and down and look as if they are dancing which gives them their common name (Borror, Triplehorn, and Johnson 1989). In addition to their elaborate swarming behavior they also exhibit interesting mating behavior. In several genera, the flies participate in a behavior known as ballooning. When looking for a mate, they catch prey and wrap it up with silk and present it to their mate as a nuptial gift (B. J. Sinclair and Cumming 2006). Dance flies exist in a variety of habitats including: running water (Wagner and Gathman 1996), tidal zones, decaying wood, and soil (B. J. Sinclair and Cumming 2006). I collected dance flies in western Mongolia in several fresh water habitats in Khovd and Bayan Olgiy Aimags.
I visited western Mongolia as part of the Mongolian Aquatic Insect Survey and traveled through the Khovd and Bayan Olgiy Aimags in July 2009 for 3 weeks to different freshwater habitats. We stopped at 2-3 sites per day and sampled each of those areas for 2-3 hours. I captured flies by overturning rocks, searching for them on rocks close to the surface of the water, and by sweeping with a standard sweep net. Once captured, the specimens were preserved in 70% ethanol and stored for examination in the laboratory. Additional specimens were also captured using yellow pan traps and malaise traps, but they have not yet been identified.
The Empididae were identified to genus using The Manual of Nearctic Diptera (Mcalpine 1989). Those identified to the subfamily Clinocerinae were identified to genus with an updated key by Sinclair (B.J. Sinclair 1995).
Thirteen genera were identified from western Mongolia collected in 2009. Fifteen genera were identified from the samples taken in the Selenge River drainage. Although 23 genera are now know for Empidoidea in Mongolia, only five were found in both the Selenge River and the 2009 collection from western Mongolia. Eight new genera were recorded for Mongolia found in 2009.
Five genera were previously recorded from Mongolia (Soos 1991). All these were represented in the Selenge River drainage, and two were found in the 2009 sample. The total number of genera now known from Mongolia is 23. Only 22% of the genera were found in both the Selenge River Basin (central Mongolia) and the Altai Mountain drainages (western Mongolia), a surprisingly high disparity between these contiguous regions. The amount of variation between these two areas suggests that it is probable that other areas of the country will also present a different generic makeup.
Different water qualities were tested at each site sampled. A previous study has looked at the correlation between dance fly assemblage structure and water temperature, dissolved oxygen, alkanility, conductivity, and pH (Kepcija et al. 2007). Future research should conduct similar analyses and look for consistencies with previous research.
I would like to thank the organizations that made this project possible. First the Office of Research and Creative Activities at BYU for their support from the undergraduate ORCA grant. This experience has really added to my experience at BYU. I would like to thank my faculty advisor, Dr. C. Riley Nelson, for his mentorship, and help on the project.
Works Cited
- Borror, Donald J., Charles A. Triplehorn, and Norman F. Johnson. 1989. Introduction to the Study of Insects, 6th Edition. 6th ed. Saunders College Pub., March 8.
- Kepcija, R., Z. Mihaljevic, B. Horvat, and M. Ivkovic. 2007. Assemblage composition and ecological features of aquatic dance flies (Diptera, Empididae) in the Cetina River system, Croatia. Fundamental and applied limnology 170, no. 3: 223-232. doi:10.1127/1863-9135/2007/0170-0223.
- Mcalpine, J. F. 1989. Manual of Nearctic Diptera. Canadian Government Publishing Center.
- Sinclair, B. J., and J.M. Cumming. 2006. The morphology, higher-level phylogeny and classification of the Empidoidea (Diptera). Zootaxa 1180 (April 21): 1-172.
- Sinclair, B.J. 1995. Generic Revision of the Clinocerinae (Empididae), and description and phylogenetic relationships of the Trichopezinae, new status (Diptera:Empidoidea). Canadian Entomologist 127, no. 5: 665-752.
- Soos, A. 1991. Catalogue of Palaearctic Diptera : Dolichopodidae-Platypezidae. Elsevier Science Ltd, June 1.
- United Nations. 2008. World Population Prospects. http://esa.un.org/unpp/.
- Wagner, Ruediger, and Oliver Gathman. 1996. Long-term studies on aquatic dance flies (Diptera, Empididae) 1983-1993: Distribution and size patterns along the stream, abundance changes between years and the influence of environmental factors on the community. Archiv fuer Hydrobiologie 137, no. 3: 385-410.
- Wilson, Edward O. 2000. The Diversity of Life. Revised. W. W. Norton & Company, February.
- Yang, Ding. 2008. A new species of Dolichocephala from Hainan Island, with a key to the Chinese species (Diptera: Empididae). Aquatic Insects 30, no. 4 (12): 281-284. doi:10.1080/01650420802334061.