Prolonged laboratory rearing as it affects host preference and reproductive capacity of Neoseiulus idaeus Denmark and Muna (Acari: Phytoseiidae)

Abstract

Host preference and reproductive capacity of both feral and colonized strains of the Colombian biotype of Neoseiulus idaeus Denmark and Muna (Acari: Phytoseiidae) were studied in the laboratory and screehouse. Two tetranychid mites Mononychellus tanajoa Bondar (the cassava green mite. CGM) and Tetranychus urticae Koch (the two spotted mite, TSM)(Acari: Tetranychidae) were used as prey in potted plant, cassava leaf lobe and artificial arena experiments. The numbers of feral and colonized strains of N. idaeus harvested from cassava leaves infested with CGM were significantly higher (P<0.05) than those harvested from leaves infested with TSM. The rate of population increase of the feral strain was significantly higher (P<0.05) than that of the colonized strain at all sampling times. Free-choice trials on field-infested leaves showed that CGM was preferred by both strains although it supported a higher non-significant population of the feral strain. Feral N. idaeus consumed fore prey eggs than the colonized strain implying higher feeding capacity. A significantly higher number of feral adult females preferred washed eggs of CGM to that of TSM, while colonized N. idaeus females showed no preference. Reduction in prey preference and reproductive capacity of N. idaeus in the laboratory is suggested