title: Evaluation of horn flies (Diptera: Muscidae) from a pyrethroid susceptible colony for general and permethrin esterase activities.
abstract: In this study we describe a nonradioactive single-fly microassay for permethrin hydrolysis. We used this assay with a microplate assay for general esterase activity to evaluate the permethrin hydrolyzing and general esterase activities of aging pyrethroid-susceptible male and female horn flies, Haematobia irritans (L.). We found substantial gender- and age-related differences regarding general esterase activity, permethrin sensitivity, and permethrin hydrolyzing activity within the colony. Extracts of female flies collected 48 h after receiving their first blood meal yielded significantly greater esterase activity than male extracts. Aging female flies were more tolerant of permethrin than were male flies. In addition, a positive correlation was found to exist between the general esterase activity of aging females and their ability to hydrolyze permethrin.
authors.affiliation: Knipling-Bushland U.S. Livestock Insects Research Laboratory, USDA-ARS, Kerrville, TX 78028, USA.
authors.forename: J H
authors.initials: JH
authors.lastname: Pruett
authors.forename: D D
authors.initials: DD
authors.lastname: Oehler
authors.forename: D M
authors.initials: DM
authors.lastname: Kammlah
authors.forename: F D
authors.initials: FD
authors.lastname: Guerrero
mesh_terms: D000367:Age Factors; D000818:Animals; D004950:Esterases / Q000378:metabolism*; D005260:Female; D006868:Hydrolysis; D007306:Insecticides; D008297:Male; D009117:Muscidae / Q000201:enzymology*; D009284:Naphthols / Q000378:metabolism; D026023:Permethrin; D011722:Pyrethrins / Q000378:metabolism*; D012737:Sex Factors
chemical_list: D007306:Insecticides; D009284:Naphthols; D011722:Pyrethrins; D026023:Permethrin; C027876:alpha-naphthyl acetate; D004950:Esterases