title: Comparison of thermal activity thresholds of the spider mite predators Phytoseiulus macropilis and Phytoseiulus persimilis (Acari: Phytoseiidae).
abstract: The lower and upper thermal activity thresholds of the predatory mite Phytoseiulus macropilis Banks (Acari: Phytoseiidae) were compared with those of its prey Tetranychus urticae Koch (Acari: Tetranychidae) and one of the alternative commercially available control agents for T. urticae, Phytoseiulus persimilis Athias-Henriot. Adult female P. macropilis retained ambulatory function (CTmin) and movement of appendages (chill coma) at significantly lower temperatures (8.2 and 0.4 °C, respectively) than that of P. persimilis (11.1 and 3.3 °C) and T. urticae (10.6 and 10.3 °C). As the temperature was raised, P. macropilis ceased walking (CTmax) and entered heat coma (42.7 and 43.6 °C), beyond the upper locomotory limits of P. persimilis (40.0 and 41.1 °C), but before T. urticae (47.3 and 48.7 °C). Walking speeds were investigated and P. persimilis was found to have significantly faster ambulation than P. macropilis and T. urticae across a range of temperatures. The lower thermal activity threshold data indicate that P. macropilis will make an effective biological control agent in temperate climates.
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, B15 2TT, UK. mrc991@bham.ac.uk
authors.forename: Megan R
authors.initials: MR
authors.lastname: Coombs
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Bale
mesh_terms: D000818:Animals; D049628:Body Size; D005260:Female; D008124:Locomotion; D008925:Mites; D009043:Motor Activity; D010572:Pest Control, Biological; D013696:Temperature