Date of Award

Spring 2003

Document Type



Life & Environmental Sciences

First Advisor

Gerald Shields

Second Advisor

John Addis

Third Advisor

Jack Oberweiser


Preliminary studies by Rhodes (2001) indicate that the IIL-3 and IIL-7 sibling species of the black fly, S. arcticum, occur at Little Prickly Pear Creek (LPPC), Lewis and Clark County, Montana. The occurrence and chromosomal diversity of S. arcticum in the various drainages east and west of the crest of the Rocky Mountains in Montana are currently being studied (Shields, unpublished data). As a part of this larger study, TenMile Creek (TMC), a tributary of LPPC, was chosen for this study. Correspondingly, I hypothesized that both the IIL-3 and IIL-7 siblings of S. arcticum would be present at TMC. The development and emergence of black flies was monitored from mid-May to the end of July of 2002. Modem cytogenetic methods were used to describe the banding sequences of the larval polytene chromosomes of the S. arcticum collected. Thus far, only the IIL-3 sibling of S. arcticum has been described at TMC. Further study both in early spring (March and April) and in late summer (August and September) is needed to completely describe the status of sibling species of S. arcticum at TMC.