Ichthyology, limnology, stream ecology, fauna of the great plains, parasitology, biosystematics, biogeography
Ichthyology/aquatic ecology: life history, ecology and systematics of North American fishes. Studies of reproduction in the minnow genus Phoxinus have demonstrated a parthenogenetic polyploid/mosaic complex in the Nebraska Sandhills. Ecological studies have been made on many Nebraskan fishes including pearl and blacknose dace, sicklefin and sturgeon chub, plains topminnow, tadpole madtom, orangethroat and Iowa darters. Field records from the past 25 years document the distribution of the state's fishes; data on population levels allows the compilation of a threatened/endangered species list. Morphological, electrophoretic, and DNA techniques have been used to investigate systematic relationships in several groups of midwestern fishes. Studies of predator/prey relationships revealed changes in behavior and physiology in Daphnia and relative spine length in sticklebacks in bodies of water without fishes.