ASSOCIATIONS OF AQUATIC COLEOPTERA WITH COARSE WOODY DEBRIS IN OZARK STREAMS, ARKANSAS

Coleoptera were collected from both coarse woody debris (CWD) and benthic habitats from the White River, Illinois River, and Clear Creek of Northwest Arkansas from February 1991 through February 1992. Overall density of beetles was significantly greater on CWD than in benthic habitats. There were no significant seasonal differences in the densities of coleopterans. Most beetles collected from CWD showed a preference for wood with loose bark, and wood that was well decayed with many interstitial spaces. All coleopteran species tested showed a preference for wood with heavy volumes of biofilm. Wood with bark remaining was more heavily colonized by beetles if the bark had a rough texture than if the bark was smooth. Wood with loose bark and/or interstitial space probably provides concealment, and thus protection from predators. Wood with heavy volumes of biofilm probably also provides cover, and may additionally provide a food source for coleopterans.