Push-up response of stonefly larvae in low-oxygen conditions

Under conditions of low oxygen availability, the larvae of the stonefly Oya mia lugubris McLachlan demonstrate a 'push-up' behavior that is thought to enhance respiratory efficiency. We conducted an experiment to investigate t he effect of the oxygen supply on this behavior in winter and summer by usi ng a lotic chamber and natural water. From the experiment, we determined th e critical oxygen supply level below which the stonefly larvae are compelle d to do push-ups. There was a small difference in the critical oxygen suppl y level between the seasons. This result emphasizes that a novel measuremen t of the oxygen availability, that is, the oxygen supply, could be an impor tant determinant of the distribution of aquatic insects.