Borborids (Diptera: Sphaeroceridae) infesting Sewage Disposal Tanks, with Notes on the Life Cycle, Behaviour and Control of Leptocera (Leptocera) caenosa (Rondani)

Abstract

AbstractA unique problem involving borborid infestations in modern septic sewage-disposal tanks is described. Two species, Leptocera (Leptocera) caenosa (Rondani) and L. (Limosina) empirica (Hutton) are new to North America. A third, yet undetermined, is related to L. (Limosina) gracilipennis Spul.Adults emerging from tanks in new schools sometimes blackened lavatory windows. Domestic septic tanks were seldom infested and chemical tanks never infested. Factors responsible, prevention and control are discussed. The main pest species, L. caenosa, was cultured. At about 72°F. the egg stage lasted about 48 hrs. and the larval and pupal stages 7 or more days each. In a humid atmosphere males survived up to 32 days and females 79 days. Fertile eggs were laid as late as 47 days after mating, with a maximum of more than 1300 eggs per female. Observations, including olfactometer tests, indicated that L. caenosa should not initiate a public health problem.