Functional and numerical responses of the predator Amblyseius swirskii to its prey Tetranychus turkestani in the laboratory

Authors: RAHMANI PIYANI, ATEFEH - Shahid Chamran University Of Ahvaz; SHISHEHBOR, PARVIZ - Shahid Chamran University Of Ahvaz; KOCHEILI, FARHAN - Shahid Chamran University Of Ahvaz; Riddick, Eric

Submitted to: Acarologia
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/12/2021
Publication Date: 10/21/2021
Citation: Rahmani Piyani, A., Shishehbor, P., Kocheili, F., Riddick, E.W. 2021. Functional and numerical responses of the predator Amblyseius swirskii to its prey Tetranychus turkestani in the laboratory. Acarologia. 61(4):901-909. https://doi.org/10.24349/r82w-YLJ1.
DOI: https://doi.org/10.24349/r82w-YLJ1

Interpretive Summary: Spider mites (Family Tetranychidae) are persistent pests of numerous crop plants throughout the world. Research is underway to evaluate the utilization of natural enemies (predatory mites) for biological control of spider mites, e.g., Tetranychus turkestani, as a safe and effective alternative to pesticides (acaricides). In this investigation, functional and numerical responses of the predatory mite Amblyseius swirskii (Family Phytoseiidae) to the pest mite Tetranychus turkestani were determined in the laboratory. The functional response, i.e., number of pest mites consumed relative to pest mite density, followed a type II response indicating that predation increased with pest density to a certain density, then leveled-off. The numerical response, i.e., number of progeny (eggs) produced by the predatory mite relative to pest mite density, increased up to 33.10 eggs per female, then leveled-off. This research indicates that the predatory mite responds positively to the population density of the pest mite. This research suggests that the predatory mite Amblyseius swirskii has great potential as a commercial biological control agent against the pest mite Tetranychus turkestani. However, follow-up experiments in the greenhouse and open field are necessary.

Technical Abstract: The tetranychid Tetranychus turkestani Ugarov and Nikolskii is a serious pest of many important crops around the world. Management of T. turkestani by augmentative biological control using predators such as the phytoseiid Amblyseius swirskii (Athias-Henriot) is envisioned as an environmentally safe alternative to acaricides. Foundational knowledge on T. turkestani – A. swirskii interactions in the laboratory are necessary to predict the outcome of A. swirskii augmentative releases in the field. In this study, the functional and numerical responses of adult A. swirskii females feeding on immature stages of T. turkestani were determined in the laboratory. Prey densities were 2, 4, 8, 16, 32, 64, or 128 individuals per Petri dish arena. The functional response of A. swirskii to prey showed a Holling's type II response. The attack rate and handling time estimates from the random predator equation were 0.1148/h and 0.3146 h, respectively, indicating that A. swirskii consumed 76.28 individuals per day at the maximum level. The number of eggs laid by the predator, i.e., the numerical response, increased as host density increased up to a maximum of 33.10 eggs per female; then oviposition rate leveled-off. This study suggests that A. swirskii is a suitable candidate for augmentative biological control of T. turkestani but follow-up experiments in greenhouses or open fields are necessary.