Jesse J. Matter

Horn Fly: Preliminary Evaluation of Media for Rearing Larvae

Larvae of the horn fly, Haematobia irritans (L.) (Diptera: Muscidae), were reared on bovine feces (F); artificial media (LM1 and LM2) containing various proportions of ground sugar cane bagasse, whole wheat flour, fish meal, baking soda, and water; and LM1 with feces added (LM1+F). When these media were seeded with newly hatched (6- to 8-hr-old) larvae, no pupae were recovered from LM1. However, with F and LMl+F, percent survival from larvae to pupae, average weight of pupae, and percent emergence of adults were statistically equal; LM2 was significantly less effective. In contrast, when these media were seeded with eggs rather than larvae, pupae were recovered from all treatments; also, the differences between treatments in overall production of pupae were less. The apparent increased production was presumably caused by the 10- to 12-hr period during which the eggs incubated. This time allowed microorganisms to begin decomposing the artificial media. As a result, nutrients were available to the larvae when they hatched. Bovine feces, therefore, appear essential for maximum production, but an artificial medium can be substituted for some of the feces.