The importance of root-produced volatiles as foraging cues for entomopathogenic nematodes

• Published in: Plant and soil Vol. 358; no. 1/2; pp. 51 - 60
• Main Authors: Turlings, Ted C. J., Hiltpold, Ivan, Rasmann, Sergio
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer 01.09.2012; Springer Netherlands; Springer Nature B.V
• Subjects: Animal behavior; Attractants; Biological control; Biomedical and Life Sciences; Carbon dioxide; Corn; Ecology; entomopathogenic nematodes; Entomophilic nematodes; Foraging; Foraging behavior; gases; helminths; hosts; insect control; Insect pests; Insects; Life Sciences; MARSCHNER REVIEW; Nematoda; Nematode larvae; Nematodes; Parasite hosts; Parasites; parasitism; Pest control; Pests; Plant biology; Plant parasitic nematodes; Plant Physiology; Plant roots; Plant Sciences; Plants; Rhizosphere; roots; Soil Science & Conservation; Trophic levels; Root volatiles; Entomopathogenic nematodes; Belowground tritrophic interactions; Foraging behavior; Carbon dioxide
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/s11104-012-1295-3

Background Entomopathogenic nematodes (EPNs) are tiny parasitic worms that parasitize insects, in which they reproduce. Their foraging behavior has been subject to numerous studies, most of which have proposed that, at short distances, EPNs use chemicals that are emitted directly from the host as host location cues. Carbon dioxide (CO2) in particular has been implicated as an important cue. Recent evidence shows that at longer distances several EPNs take advantage of volatiles that are specifically emitted by roots in response to insect attack. Studies that have revealed these plant-mediated interactions among three trophic levels have been met with some disbelief. Scope This review aims to take away this skepticism by summarizing the evidence for a role of root volatiles as foraging cues for EPNs. To reinforce our argument, we conducted olfactometer assays in which we directly compared the attraction of an EPN species to CO2 and two typical inducible root volatiles. Conclusions The combination of the ubiquitous gas and a more specific root volatile was found to be considerably more attractive than one of the two alone. Hence, future studies on EPN foraging behavior should take into account that CO2 and plant volatiles may work in synergy as attractants for EPNs. Recent research efforts also reveal prospects of exploiting plant-produced signals to improve the biological control of insect pests in the rhizosphere.