Diel patterns of oviposition and influence of agitated water surface in Chironomus anonymus (Diptera:Chironomidae).

A series of experiments was carried out in a 0.5-ha lake at Portola Country Club, Palm Desert, CA, to study the oviposition habits of Chironomus anonymus. Egg masses were collected by floatable polypropylene ropes attached to the 1.5-m-long stakes placed in the lake. In the diel experiment, ropes were changed every 2 h to determine the preferred oviposit on periods of C. anonymus. The peak of oviposition was between 1900 and 2100 h. For the interruption of oviposition experiment, ropes were placed in the still and agitated portions of the lake for 24 h. A significantly higher number of egg masses, according to applied t-test, was collected from the ropes placed in the still portion of the lake.