A COMPARISON OF KEY TAXONOMIC FEATURES OF FIELD COLLECTED AND LAB REARED STONEFLIES IN THE TALLAPERLA MARIA COMPLEX (PLECOPTERA: PELTOPERLIDAE).

K.A. Gogolin and G.M. Ward. Department of Biological Sciences, University of Alabama, Box 870206, Tuscaloosa, AL 35487-0206

Nymphs in the genus Tallaperla are an important and frequently encountered member of the shredder community in many streams in central and northern Alabama. Three of the six valid species of Tallaperla have been found here: T. cornelia, T. laurie, and T. maria. At present, species distributions within Alabama are unclear and species identification is difficult. There are no species-specific characters in Tallaperla nymphs, and adult females are difficult to distinguish without the presence of eggs. Species separation in the adult males is made largely on the aspect ratio of the knob (previously called vesicle) of the ninth abdominal segment, as well as measurements of the epiproct and mesal sclerites. Unfortunately, we have observed substantial overlap in the aspect ratio of the knob among specimens collected in Alabama, leading to uncertainty with regard to species identification in some of our previous ecological studies here in Alabama. The major objective for this study was to use SEM to closely examine key taxonomic features (e.g., knob, cerci, epiproct and paraproct) in field collected and reared specimens in the Tallaperla maria Complex. The resulting character variability analysis will provide data to make more reliable species identifications.