Haematobia Irritans - Mutations and Known Variations

Mutations and Known Variations

A white-eyed "albino" horn fly was discovered in a colony maintained at the Knipling-Bushland U.S. Livestock Insects Research Laboratory in Kerrville, Texas. This is apparently a spontaneous mutation, as tests including crosses were performed that determined the white-eye mutation was not sex-linked and the white-eyed flies actually have decreased amounts of eye pigment present within the head. This appears to be an inherited simple Mendelian autosomal recessive with complete penetrance. A colony of white-eyed horn flies was established from this single individual and has been maintained in the laboratory as visible genetic markers such as an eye color mutation in an economically important species like the horn fly may be useful for behavior and population dynamic studies, as well as release and recapture studies. No other differences from the wild-type flies were detected in the external characteristics of the mutant phenotype or in egg viability. However, white-eyed flies had significantly lower amounts of the pigment dihydroxyxanthommatin in their heads suggesting either the lack of xanthommatin production, or a failure of transport and storage within the head of the mutant phenotype.