The Lack of Knowledge Concerning the Empididae of Navarino Island

The Lack of Knowledge Concerning the Empididae of Navarino Island

            The flies of the family Empididae and the aquatic invertebrates of Navarino Island, Chile, are researched far less in comparison to other aquatic flies and vertebrate species, respectively. By studying the Empididae of Navarino Island, new information could be acquired both for the fields of taxonomy and freshwater ecology.

            The family Empididae is composed of small, predaceous flies, commonly referred to as “dance flies” due to their courtship displays. While not all of the species have aquatic life stages, around 660 species do have aquatic larvae and pupae (Wagner, 2008).  These aquatic larvae are important to their ecosystems both as predators and prey, feeding on smaller insects and being eaten by larger organisms. While these larvae have potential to be used as indicators for the health of the streams they live in, so few larvae have been linked to their adult forms that there is almost no way to identify them to the species level (MacDonald, 1999). Due to this, the family does not appear in nearly as much literature as other aquatic flies such as Chironomidae which are well described in all stages. Because this is coupled with the decline of taxonomists specializing in aquatic flies (Wagner, 2007), the family Empididae seems unlikely to be seen as useful for stream ecologists to study unless major developments are made in the identification of its species.
            Navarino Island, Chile, is part of the Cape Horn Biosphere Reserve and contains the Robalo watershed, one of the most pristine watersheds in the world (Anderson, 2007). This island contains the southernmost city in the world, Puerto Williams, and is considered to be in the sub-Antarctic ecoregion. While the vertebrates of the region, both native and invasive, have been heavily researched, little is currently known about the freshwater invertebrates (Moorman, 2006). This difference in attention may be attributed to the vertebrates being more “charismatic” and gaining the researchers more funding, but it creates problems due to the invertebrates typically playing a larger role in the healthy functions of streams than vertebrates do.

While the Empididae of the general area around Navarino Island area have been described (Collin, 1933), it has been a long time and the phylogeny of the family has greatly changed in recent years (Plant, 2011). The area is not predicted to have a large species diversity (Plant, 2011), and recent studies that identified down to the genus level found only one genera among several watersheds (Moorman, 2006). But, several new species have been identified in the last ten years around the world and it is possible that, due to the number of endemic aquatic insect species that are found in the area, some species of Empididae there may have been misidentified.

The matching of known adult species to their corresponding larvae could turn the Empidiade of the region into potential tools for stream quality assessment. It may be possible to match the adults and larvae using genetic tests, as this has been successful in the past (MacDonald 1999).Samples have been gathered for the last three years from the Robalo watershed to be analyzed and used as baseline data to compare against in the future (Contador, unpublished). If the Empididae from these samples can be identified to all developmental levels, they can be used as references for species diversity along with the better-known families.

Anderson, C.B. and Amy D. Rosemond, 2007. Ecosystem Engineering by invasive exotic beavers reduves in-stream diversity and enhances ecosystem function in Cape Horn, Chile. Ecosystem Ecology, 154: 141-153.

Collin, J. E., 1933. Diptera of Patagonia and South Chile, Based Mainly on Material in the   British Museum (Natural History); Part IV -- Empididae.

Contador, Tamara. Unpublished Material.

MacDonald, John F., and James R. Harkrider. Differentiation of Larvae of Metachela Coquillett and Neoplasta Coquillett (Diptera:Empididae:Hemerodromiinae) Based on Larval Rearing, External Morphology, and Ribosomal DNA Fragment Size. Journal of the North American Benthological Society 18: 414-419.

Moorman, M.C., C.B. Anderson, A. Gutiérrez, R. Charlin, & R. Rozzi, 2006. Watershed
conservation and aquatic benthic macroinvertebrate diversity in the Alberto D’Agostini
National Park, Tierra del Fuego, Chile. The Anales 34: 41-58.

Plant, Adrian R., 2011. Hemerodromiinae (Diptera: Empididae): a tentative

phylogeny and biogeographical discussion. Systematic Entomology, 36: 83-103.

Wagner, R., Bartàk, M., Borkent, A., Courtney, G., Goddeeris, B., Haenni, J.-P.,

Knutson, L., Pont, A., Rotheray, G.E., Rozkosny, R., Sinclair, B., Woodley, N.,

Zatwarnicki, T., Zwick, P., 2008. Global diversity of dipteran families (Insecta

Diptera) in freshwater (excluding Simulidae, Culicidae, Chironomidae, Tipulidae

and Tabanidae). Hydrobiologia 595, 489-519.

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This paper has been a challenge for me, mostly because of the lack of information out there about the region/family. That lack of information has become the topic of the paper, more or less, and I'm not sure if that's a good thing. If I can find more information in the next few weeks, this paper could change quite a bit. If not, I'll just be expanding on this.