The objective of this collaborative research is to test predictive models regarding the effects of boundary layer flow on the ecology of larval black flies, important stream insects. Specifically, the project will determine the direct effects of drag, average velocity, local flow disturbances and background turbulence on larval behavior, growth and distribution, as well as the indirect effects of flow on competition and predator-prey interactions. Black fly larvae are excellent experimental subjects for laboratory and field studies, because they rapidly respond to changes in flow, have high feeding and growth rates, and occur in dense populations in local streams. Video equipment will record larval feeding and spacing behavior, submerged force plates will measure larval drag, and hot film anemometry will characterize the fluid environment on spatial and temporal scales that are relevant to these small stream organisms. The results will represent a significant advance in boundary layer hydromechanics and stream ecology. The field studies are important because they will be the first to quantify the influence of small-scale turbulence on benthic organisms. Results will allow evaluation of adaptive paradigms and assessment of the non-catastrophic costs of drag. The information from this study will provide important insights that may be applied to physical ecology of other benthic organisms.
