Estimating densities of larval Salmonflies (Pteronarcys californica) through multiple pass removal of post-emergent exuvia in Colorado rivers.

Traditional methods of collecting, sorting, and identifying benthic macroinvertebrate samples are useful for stream biomonitoring and ecological studies, however, these methods are time consuming, expensive, and require taxonomic expertise. Estimating larval densities through collection of post-emergent exuvia can be a practical and time efficient alternative. We evaluated the use of multiple pass depletion techniques of the post-emergent exuvia of Pteronarcys californica to estimate larval densities at ten sites in three Colorado rivers. Exuvia density was highly correlated with both final-instar larval density (R2 = 0.90) and total larval density (R2 = 0.88) and the multiple pass removal technique performed well. Exuvia surveys found P. californica at three low density sites where benthic sampling failed to detect it. At moderate and high density sites the exuvia surveys always produced lower density estimates than benthic surveys. Multiple pass depletion estimates of exuvia proved to be an accurate and efficient technique at estimating larval densities and provided an effective alternative for traditional benthic sampling when objectives are detecting and monitoring P. californica, especially at low density sites.

Discovery of new populations and DNA barcoding of the Arapahoe snowfly Arsapnia arapahoe (Plecoptera: Capniidae).

The Arapahoe Snowfly, Arsapnia arapahoe (Nelson & Kondratieff)was recently discovered in six different first-order streams outside of the Cache la Poudre River Basin where it was previously considered endemic. Specimens of A. arapahoe were always collected in much lower relative abundance, 1.09% (±2.3SD), than other sympatric adult capniids. The first mitochondrial deoxyribonucleic acid (DNA) barcodes for A. arapahoe and A. coyote (Nelson & Baumann) are presented and compared with those of A. decepta. DNA barcoding was not able to differentiate between A. arapahoe and A. decepta Banks but it was able to indicate that A. coyote is specifically distinct.