Jack E. Ruggirello Christopher C. Nack James H. Johnson 2012 We examined diel feeding periodicity of <i>Ephemera simulans</i> nymphs during summer and winter in a third-order stream in central New York. A total of 245 nymphs were collected at 4-h intervals over two 24 h periods and were immediately preserved in 80% ethanol. In the laboratory, we weighed each nymph and its digestive tract. The ratio of wet weight of the digestive tract to the total body weight at each 4-h interval was used to determine feeding periodicity. Diel feeding periodicity followed a similar pattern in summer and winter and was significantly higher at 08:00 hours. Feeding periodicity of <i>E. simulans</i> in Labrador Creek is asynchronous with the two most abundant fish species in the stream and may reflect predator avoidance behavior that has been shown for other mayfly species. application/pdf 10.1080/02705060.2012.659221 en Taylor & Francis Group Diel feeding periodicity of <i>Ephemera simulans</i> nymphs in summer and winter article