Mixed blends of herbivore‐induced plant volatiles and foraging success of carnivorous arthropods

Abstract

Dicke, M., de Boer, J. G., Hö fte, M. and Rocha-Granados, M. C. 2003. Mixed blends of herbivore-induced plant volatiles and foraging success of carnivorous arthropods. Oikos 101: 38 -48.Food webs are overlaid with infochemical webs that mediate direct and indirect interactions. Behavioural ecologists have extensively documented that carnivorous arthropods exploit herbivore-induced plant volatiles during foraging for herbivorous arthropods. Most studies on the role of infochemicals in multitrophic interactions have been conducted against an odour-free background, although field studies show that carnivores also use herbivore-induced plant volatiles under more complex conditions. Here we investigated the effect of mixing the blends of volatiles emitted by two plant species on the foraging behaviour of the predatory mite Phytoseiulus persimilis. This was done in an olfactometer under laboratory conditions and in a semi-field setup under greenhouse conditions. The olfactometer setup ensured directed mixing of the two odour blends, while odour mixing in the greenhouse setup was much less controlled and resulted from diffusion. In 4 out of 5 olfactometer experiments the behaviour towards volatiles from spider-mite (Tetranychus urticae) infested Lima bean plants was not affected by mixing with volatiles from caterpillar (Pieris brassicae) infested Brussels sprouts plants. In the fifth olfactometer experiment the response shifted significantly towards the volatiles from infested Lima bean leaves without volatiles from infested cabbage leaves. In the greenhouse setup no effect of infested cabbage plants or their volatiles on the location of spider-mite infested bean plants was recorded. The two odour blends used in this study, i.e. those from spider-mite infested Lima bean leaves and from caterpillar-infested Brussels sprouts plants, are very different and there is no overlap in compounds that are known to attract the predators. The results are discussed in the context of other types of odour-blend mixing and the effects on food web interactions.

Can plants betray the presence of multiple herbivore species to predators and parasitoids? The role of learning in phytochemical information networks

“…A number of cases have been reported where predatory arthropods and parasitoids respond to HIPV from plants with non-prey or non-host herbivores (Agrawal and Colfer 2000;Shimoda and Dicke 2000;Thaler et al 2002;Dicke et al 2003;Van Poecke and Dicke 2003;A. Janssen and M. Van Wijk 2005, unpublished data).…”

Information use by the predatory mite Phytoseiulus persimilis (Acari: Phytoseiidae), a specialised natural enemy of herbivorous spider mites

“…1). Besides the olfactometer, we used a greenhouse set-up that resembled the situation in the field more closely, with intact plants standing in soil (Pallini et al, 1997;Janssen, 1999;Dicke et al, 2003a). This experiment confirmed that the foraging efficiency of predatory mites was not hampered by the presence of P. brassicae-infested brussels sprouts plants (Dicke et al, 2003a).…”

“…Moreover, P. persimilis was not attracted to the volatiles from P. brassicae-infested brussels sprouts plants (Dicke et al, 2003a). This may indicate that the volatiles emitted by P. brassicae-infested brussels sprouts plants do not play a role in the foraging behaviour of P. persimilis and therefore do not disturb its foraging efficiency when mixed with volatiles from prey-infested bean plants.…”

“…We investigated how the attraction of P. persimilis to volatiles induced by their prey was influenced by volatiles from Pieris brassicae-infested brussels sprouts plants (Dicke et al, 2003a). Pieris brassicae is not suitable as prey for P. persimilis, and brussels sprouts plants are poor host plants for spider mites.…”

Host plants and aphid hosts influence the selection behaviour of three aphid parasitoids (Hymenoptera: Braconidae: Aphidiinae)

“…Successful parasitism requires a series of interactions among parasitoids, their hosts and host plants, including habitat fi nding, host location, host acceptance, host suitability and host regulation (Vinson, 1976(Vinson, , 1984Hatano et al, 2008;Rasekh et al, 2010). Parasitoids may respond to semiochemical cues during antennal contact and ovipositor probing (Muratori et al, 2006;Larocca et al, 2007) and volatile chemical compounds emitted by damaged plants (Turlings et al, 1990, Mattiacci et al, 1994, Dicke et al, 2003. Host selection by parasitoids may be infl uenced by the insect host, the plant on which the insect hosts are feeding and by conditioning of females to the host on which they developed (Chau & Mackauer, 2001).…”