title: Fitness costs associated with low-level dimethoate resistance in Phytoseiulus macropilis.
abstract: Phytoseiulus macropilis Banks (Acari: Phytoseiidae) is an effective predator of tetranychid mites, but there are no data on its response to pesticides. We investigated the resistance of the predatory mite P. macropilis to the acaricides abamectin and dimethoate, and we examined the fitness costs associated with resistance. Two populations were tested: one from conventional cultivation and another from an area not commercially exploited. After the application of acaricides to the predator, we determined the lethal effects of the acaricides, the instantaneous rate of population increase (r(i)), the predation on Tetranychus urticae Koch (Acari: Tetranychidae) and its ability to locate prey in an olfactometer. P. macropilis exhibited resistance to dimethoate only. The low level of resistance (9.4x) of the predator did not affect their ability to locate prey. However, the dimethoate resistant population was not as effective in contatining prey population when in lower density and exhibited a more pronounced decrease of r(i) in the presence of this acaricide, due to the reduced oviposition of the predator, a likely consequence of the different genetic background of this population.
authors: Departamento de Agronomia; Entomologia, Universidade Federal Rural de Pernambuco, Av. Dom Manoel de Medeiros s/n, Dois Irmãos, Recife, PE 52171-900, Brazil. daniagroufv@hotmail.com
authors: D D M
authors: DD
authors: Rezende
authors: M A M
authors: MA
authors: Fadini
authors: H G
authors: HG
authors: Oliveira
authors: C M
authors: CM
authors: Oliveira
authors: J W S
authors: JW
authors: Melo
authors: R N C
authors: RN
authors: Guedes
authors: A
authors: A
authors: Pallini
mesh_terms: D000818:Animals; D004117:Dimethoate / Q000633:toxicity*; D004351:Drug Resistance / Q000235:genetics*; D007306:Insecticides / Q000633:toxicity*; D008925:Mites / Q000187:drug effects* / Q000235:genetics; D010572:Pest Control, Biological; D011156:Population Density; D011235:Predatory Behavior / Q000187:drug effects*; D040102:Tetranychidae / Q000502:physiology; D018675:Toxicity Tests
chemical_list: D007306:Insecticides; D004117:Dimethoate