TUBES AND TUBE-BUILDING IN A LOTIC CHIRONOMID (DIPTERA) COMMUNITY

The use of particles for the construction of tubes by a community of stream-dwelling midge (Chironomidae [Cricotopus spp., C. tremulus, C. trifascia, C. nostocicola, Orthocladius spp., O. rubicundus, Microtendipes sp., Polypedilum sp., Microspectra sp., Rheotanytarsus pentapoda and Tanytarsus spp.]) larvae was investigated. The particles present in larval tubes occurred in the same proportions as those present on the surfaces of stones in the stream. Small particles were principally of detritus, medium-sized particles mainly of detritus and diatoms, and a variety of types of particles, including filamentous algae and sand grains, occurred in the large size category. The absence of particle selection in the field was reflected in laboratory experiments. Competition for suitable available space in which to build tubes and the quantity of building material may be more significant to the larval community in upland streams than particle size or type.