Oral delivery of water-soluble compounds to the phytoseiid mite Neoseiulus californicus (Acari: Phytoseiidae).

Noureldin A Ghazy,Takeshi Suzuki,Yonggen Lou

doi:10.1371/journal.pone.0223929

Noureldin A Ghazy, Takeshi Suzuki + Show 1 more

Open Access

https://doi.org/10.1371/journal.pone.0223929

Copy DOI

Abstract

Phytoseiids are predatory mites that prey on other mites and small arthropods, and several species are used in commercial agriculture for biological control of pests. To optimize phytoseiid mites’ use in biocontrol, an efficient method for oral delivery of test compounds is required to assess their sensitivities to pesticides, RNAi for gene functional analysis and artificial diets. Here we developed four methods for oral delivery of a solution of xenobiotics to different life stages of the commercially available generalist predatory mite Neoseiulus californicus: (i) soaking mites in the solution, or allowing them to feed on (ii) spider mites soaked in the solution, (iii) a solution droplet, or (iv) solution-saturated filter paper. As measured by ingestion of a tracer dye, the droplet-based feeding system was most efficient; the dye was observed in the alimentary canal of >90% test mites of all life stages, with no mortality. The droplet-based feeding system was also effective for the commercially available specialist predatory mite Phytoseiulus persimilis, with >80% delivery efficiency. This study paves the way for development of methods for high-throughput RNAi and for toxicological or nutritional assays in phytoseiid mites.

Highlights

Predatory phytoseiid mites (Acari: Phytoseiidae) are an economically important group of mites that prey on other mites and small arthropods
No mortality was observed in adult females of N. californicus after 24 h feeding on soaked adult females of T. urticae, regardless of prior starvation (P > 0.05, Fisher’s exact test) (Fig 5a)
Delivery of liquid substances to phytoseiid mites is relevant for bioassays for pesticide sensitivity, RNA interference (RNAi)-based reverse genetics, and commercial production

Summary

Introduction

Predatory phytoseiid mites (Acari: Phytoseiidae) are an economically important group of mites that prey on other mites and small arthropods. Several phytoseiid mites are widely and extensively used for agricultural biocontrol of pest mites and several insect species, as an alternative to chemical pesticides [1]. Neoseiulus californicus (McGregor) and Phytoseiulus persimilis Athias-Henriot, as well as several other species, are currently available as commercial products for use in managing spider mite populations in greenhouses and open fields [2,3,4,5]. Delivery of xenobiotics to predatory mites is becoming an important research target because it can aid in evaluating selective pesticides that do not affect beneficial mites and in testing of new and promising genetic-based pest management technologies such as RNA interference (RNAi)–mediated gene silencing.

Methods

Results

Conclusion