Distribution of Sibling Species of the Black Fly, Simulium arcticum, is Correlated with Elevation

Abstract

The cytogenetics of Simulium arcticum complex was studied at Boulder River drainage. Conventional methods for collection, morphological classification, and preparation and analysis of polytene chromosomes were used. Three sites were chosen on the Boulder River to determine if a correlation existed between distribution of siblings and elevation: Cardwell (low elevation), High Ore (intermediate elevation), and Bison Creek (high elevation). Moreover, as part of a coordinated effort, results of this study were compared to the results obtained by two other students at two separate drainages under the assumption of the same hypothesis. Results showed that the low elevation site at Cardwell was exclusively S. apricarium with an absence of S. arcticum sensu strictu and that S. arcticum s. s. was dominant at the intermediate elevation site and had a significant presence at the high elevation site. Additionally, results showed an increase in IIL standard individuals with increasing elevation. These observations, at least for these siblings in this drainage, suggest a correlation between genetic diversity and the elevation or temperatures at which these flies emerge.