PS 3-26
Diversity and ecology of arctic Rhamphomyia dance flies (Diptera: Empididae)
Climate change impacts are pronounced in the Arctic. Increases of both mean annual temperature and precipitation alter primary production, and consequently, arctic arthropod community composition and distribution. Arthropods have a very short generation time and hence respond quickly to environmental change. Studying arthropod community structure and distribution is key to assessing the extent of ecosystem changes in the Arctic caused by climate change. Diptera is the most dominant insect order in the Arctic and includes some of the most ecologically diverse families. The dance flies (family Empididae) contain one of the most abundant, species rich and ecologically diverse arctic genera, Rhamphomyia. This project has three components: taxonomy, inventory, and ecology of northern Rhamphomyia. Samples from twelve sites in the boreal, low arctic, and high arctic zones were collected in the summers of 2010, 2011, and 2013. Specimens are sorted to named species or morphospecies, to compile an inventory of Rhamphomyia across the twelve sites. Identifying Rhamphomyia to morphospecies/species is essential to discern ecological patterns in both space and time. The inventory provides baseline data for addressing the ecological questions about species distribution in space and in time.
Results/Conclusions
Almost 70 Rhamphomyia morphospecies were identified. Sites with low species richness (high arctic), have 1-2 abundant species, whereas sites with high species richness (low arctic, boreal) have higher evenness. Beringian Yukon is an exception, with 47 species, including some of the most abundant morphospecies. The largest and most abundant morphospecies occur in the high arctic; the smallest and less common morphospecies are low arctic. Bigger bodies reduce heat loss, but require more energy. This could explain the low species richness and dominance of few, bigger, Rhamphomyia morphospecies in the high arctic. Preliminary results suggest that species widespread across the Arctic are smaller in the south and bigger in the north. I predict that widespread species across the arctic are found in the high/low arctic at the same time as in the lower arctic but for a shorter time interval. Preliminary analysis of 15 Rhamphomyia species from season-long sampling at Kugluktuk, Nunavut (late June – mid-August) shows weekly turnover in activity periods of species through the season, generally with 4-5 species active per week. Co-occurring species were generally distributed among large, medium and small body size classes.