title: Fitting the Gompertz function to dose-response data of larval tick populations.
abstract: Samples of 6, 1st generation larval populations of Boophilus decoloratus, originating from field collected females, were subjected to increasing doses of the organophosphate acaricide, Dioxathion. The dose-response relationship for 3 populations showed random heterogeneity, while systematic deviations from the linear probit lines were observed for the other 3 populations. Logistic and Gompertz regressions were also fitted for all 6 populations. Probit regressions fitted best for 2 populations exhibiting heterogeneous responses. The logistic regression fitted best for 1 population with heterogeneous responses and 1 population with systematic deviating responses. The Gompertz regression fitted best for the 2 remaining populations exhibiting systematic deviating responses. The Gompertz function may be useful in describing the dose-response relationship obtained for certain acaricidal toxicity tests.
authors.affiliation: Veterinary Research Institute, Onderstepoort, South Africa.
authors.forename: A M
authors.initials: AM
authors.lastname: Spickett
authors.forename: H
authors.initials: H
authors.lastname: van Ark
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D007306:Insecticides / Q000008:administration & dosage*; D007814:Larva / Q000187:drug effects; D009946:Organothiophosphorus Compounds / Q000008:administration & dosage*; D012044:Regression Analysis; D013987:Ticks / Q000187:drug effects*
chemical_list: D007306:Insecticides; D009946:Organothiophosphorus Compounds; C004838:dioxathion