Surviving in anoxic surroundings: how burrowing aquatic insects create an oxic microhabitat

We used an infrared video system and O2 microelectrodes to record the behavior of 2 widespread burrowing insects, the predatory alderfly Sialis velata and the sediment-feeding mayfly Hexagenia limbata, to determine how they survive in anoxic sediment. Analysis of video recordings showed that both taxa have several common behaviors, including crawling, pushing sediment, turning around, and brushing their legs over their bodies for the purpose of cleaning. In contrast, these taxa differ in how they draw overlying oxic water into their burrows, i.e., H. limbata beats its abdominal gills, whereas S. velata undulates its abdomen. Feeding frequency also differs between the 2 taxa, i.e., the mayfly feeds frequently on sediment within its burrows, whereas S. velata feeds infrequently. Hexagenia limbata nymphs were rarely inactive (