Meeting Abstract
Stream insects must cope with and respond to changing abiotic conditions in their immediate habitat. The major abiotic factor influencing stream organism physiology, morphology, and behavior is water movement. Physical forces (i.e. – drag and lift) associated with water movement will influence how an insect resides on benthic substratum. For this reason, body shape couples organism morphology to turbulent stream flow. Previous work conducted has identified correlative evidence of Acroneuria sp. (Perlidae) body shape morphology and flow characteristics of the habitat. We wanted to evaluate this further to identify behavior (postural) changes and associated drag experienced by the animal with respect to individual body shape morphology under increasing water velocity. Acroneuria lycorias were collected from three streams in Michigan’s Northern Lower Peninsula and retained in artificial stream channels. Individuals were placed on a platform attached to a Phidgets load cell (0 – 100g) in a recirculating flume while water velocity was controlled by a rheostat propeller. Behavior and drag measurements were simultaneously recorded for each animal while alive and dead in an attempt to separate behavior and morphological effects on drag. A preliminary geometric morphometrics approach quantified variation in body shape morphology. As a result of body shape variation, A. lycorias appear to have particular behaviors to counteract the force of drag on the body. Understanding body shape morphology and associated behavior can help elucidate important flow characteristics of the stream habitat.
