Olfactory responses of Phytoseiulus persimilis to rose plants with or without prey or competitors

B Maleknia,A Saboori,S Magalhães,A Zahedi Golpayegani

doi:10.1051/acarologia/20132096

Abstract

Predators of herbivores use plant volatiles to find patches with prey. Plants benefit from this attraction as predators will reduce herbivore damage. Plants also benefit from arresting predators before prey arrival, as this will minimize future herbivore damage. For predators, however, the benefits of being attracted to clean plants depends on alternative food and on the degree of competition on other plants. Although the interactions between the predatory mite Phytoseiulus persimilis and its plant host are well-studied on cucumber or bean, that with other plants remain largely unknown. Here, we studied the olfactory response of P. persimilis to volatiles of rose plants that were either clean (i.e., empty), occupied by their prey (Tetranychus urticae) or by conspecific competitors, using bean and cucumber as comparisons. We found that, relative to clean air, predators were attracted to clean plants, and also to plants with prey. On cucumber and bean, naive predators preferred plants with prey over clean plants, but no such discrimination occurred on rose plants. However, after 24 hours of experience with rose plants infested with T. urticae, predators preferred those plants to clean roses. Predators avoided plants with prey and conspecifics, even without any previous experience. Our results show that predator attraction to plants hinges on the plant species and on experience. Attracting predators to clean plants may favour biological control, as plants may become better guarded from herbivores, but it may also be detrimental, as predators may starve on those plants.

Highlights

Several invertebrates are passive dispersers, they do not have control on where they land (Bilton et al, 2001; Kennedy and Smitley, 1985; Moser et al, 2009)
We investigate the attraction of predators towards volatiles produced by plants under different ecological contexts, using a system composed of the predatory mite Phytoseiulus persimilis (Athias-Henriot), its prey Tetranychus urticae (Koch) and rose plants
When given the choice between odours from clean rose plants and odours from rose plants infested with prey (T. urticae), predators did not discriminate between these plants (Figure 3a, Table 1)

Summary

INTRODUCTION

Several invertebrates are passive dispersers, they do not have control on where they land (Bilton et al, 2001; Kennedy and Smitley, 1985; Moser et al, 2009). Other studies have shown that predators of herbivores are able to avoid plants with competitors (Janssen et al, 1997; Zahedi-Golpayegani et al, 2007) or with their own predators (Magalhães et al, 2005; Venzon et al, 2000), but this is not always the case (Janssen et al, 1999). In this ecological context (the presence of plants harbouring different species), the interests of predators and plants may be aligned or conflicting. We will ask (1) are predators attracted to clean plants?; (2) can predators discriminate between clean plants and plants infested with prey?; (3) can they discriminate between clean plants and plants with prey and competitors?; (4) are these responses affected by the predators’ experience? and (5) are prey attracted to clean plants?

MATERIALS AND METHODS

RESULTS

DISCUSSION