Tube length of chironomid larvae as an indicator for dissolved oxygen in water bodies.

Tube-building larvae of non-biting midges, or chironomids, are considered bioindicators of water pollution. The larvae use benthic particles to make their tubes and create a respiratory current with the movement of their bodies inside the tubes. The tube length of the chironomid larvae varies depending on several physicochemical properties of the aquatic medium. Here we study the role of physicochemical parameters on the tube length from different field sites and in the laboratory. It appears that among different physicochemical factors, dissolved oxygen (DO) has a major role in determining the tube length of the larvae. A quantitative relationship between oxygen concentration and the tube length of larvae is presented here. Our study reveals a longer tube in aquatic media with oxygen deficiency and a shorter tube in those with higher oxygen. This result may help to assess the quality of water bodies and, in particular the status of DO.