The ancestral basis of sex determination in the housefly is believed to be regulated by a gene, M, that is located on the Y chromosome (YM). However, flies collected from throughout the world have been found in which the M factor is located on any one of the 5 autosomes. In Florida 100% of the males possessed the M factor on the third autosome (IIIM). North Carolina had 20% IIIM males and 2.35% with both the YM and IIIM determination. Fewer IIIM males were found in New York (4.3%). Populations from Maine contained 100% XY males. Thus, there is a strong clinal relationship (29° latitude in Florida to 47° in Maine) with the percentage of autosomal males decreasing as latitudes increase. Autosomal males were not limited to field populations, but were also found in 100% of the males in two standard laboratory susceptible strains: CS (IIIM) and SRS (VM). Insecticide bioassays of field collected and two laboratory susceptible strains revealed that resistance is not correlated with sex determination over a broad range of insecticides. For example, high levels of resistance to permethrin (84.5% to 98.7%) were found in all four field collected strains. The five other insecticides evaluated showed varying levels of resistance between field strains.
Species 1: Diptera Muscidae Musca domestica (house fly)
Keywords: sex determination
Back to Student Competition Display Presentations, Section B. Physiology, Biochemistry, Toxicology, and Molecular Biology
Back to Student Competition Posters
Back to The 2003 ESA Annual Meeting and Exhibition