A versatile laboratory stream with examples of its use in the investigation of invertebrate behaviour

A versatile and simple laboratory stream was designed and used to investigate the burrowing activity of two insects in response to changes in water velocity and substrate type.Aphelocheirus aestivalis adults were unable to burrow into sand, however, a small proportion of juveniles did burrow in this substrate. The presence of sand in gravel reduced the burrowing success of adults. Steady increases in flow stimulated the burrowing response of both adults and juveniles on gravel and sandy gravel.Ephemera danica was unable to burrow in sand alone at the velocities used in the experiment. The presence of particles greater than 2 mm in diameter in the substrate appeared to be essential for successful burrowing under the test conditions. An increase in flow from 3 to 8 cm s^–1 resulted in an increase in burrowing. The time taken for each specimen to burrow varied widely within replicate tests but most specimens had penetrated the substrate within 150 seconds of introduction. The implications of these observations in influencing the microdistribution of these species are discussed.