Biology of the snail-killing fly, Sepedon spangleri Beaver (Diptera: Sciomyzidae). II. Ability of the larvae to kill snails of medical importance in Thailand.

S. spangleri larvae preferred five species of non-operculate snails; Gyraulus convexiusculus Hutton, Segmentina hemisphaerula Benson, Hippeutis umbilicalis Benson, Indoplanorbis exustus Larambergue, and Trochobis trochoideus Benson. They occasionally consumed the operculate snails: Melanoides tuberculata Muller, Lithoglyphopsis aperta, Hubendickia siamensis Brandt, Lacunopis munensis Brandt, Tarebia granifera, Lamarch and Viviparus sp. but were innocuous to Bithynia laevis Lea.

Biology of the snail-killing fly, Sepedon spangleri Beaver (Diptera: Sciomyzidae). I. Life history.

One complete generation of the sciomyzid fly, S. spangleri, was on the average 27.90 days at 25 +/- 3 degrees C. The egg stage lasted 3.55 days. The first, second and third instar larvae lasted 4.35, 2.95 and 4.45 respectively when fed with live snails, Australorbis glabratus. Pupae floated on the water surface for 8 days until they emerged as adults. The longevity of adults fed with crushed snails, dried milk, brewer's yeast and honey average 199.95 days for females and 136.80 days for males. Under these conditions the average number of eggs laid per female was 414.70.