Meeting Abstract

P3.123  Jan. 6  Temporal Dynamics of Asilids in a Chihuahuan Desert Ecosystem LEASE, H.M.*; WOLF, B.O.; Univ. of New Mexico; Univ. of New Mexico hlease@unm.edu

Robber flies (Family Asilidae) were sampled from Chihuahuan Desert grasslands and shrublands at the Sevilleta LTER site, in central New Mexico, to investigate temporal patterns in species composition and isotopic signal. Greater than 20 species of Asilids occur over a 6 month period in this system, with only a subset of these species occurring at any one moment in time. These species demonstrate three orders of magnitude in size variation, variable flight windows, and based on when they occur, are faced with different potential prey assemblages. They additionally occur in an ecosystem that is characterized by a temporal shift in plant carbon isotope signature, which is reflected in the tissues of higher order consumers (e.g. lizards and rodents), and presumably, robber flies (which feed predominantly upon plant-feeding insects). Asilids thus offer a unique opportunity to investigate patterns in body size, community ecology, species turnover, and diet. Here I present data on >10 species of Asilids that occur sympatrically on the Sevilleta LTER site, collected over two six month sampling periods. Results show temporal patterns with respect to body size, species composition, and isotopic signal.