Habitat selection of a parasitoid mediated by volatiles informing on host and intraguild predator densities

Abstract

To locate and evaluate host patches before oviposition, parasitoids of herbivorous insects utilize plant volatiles and host-derived cues, but also evaluate predator-derived infochemicals to reduce predation risks. When foraging in host habitats infested with entomopathogenic fungi that can infect both a parasitoid and its host, parasitoids may reduce the risk of intraguild predation (IGP) by avoiding such patches. In this study, we examined whether the presence of the entomopathogenic fungi Metarhizium brunneum and Beauveria bassiana in soil habitats of a root herbivore, Delia radicum, affects the behavior of Trybliographa rapae, a parasitoid of D. radicum. Olfactometer bioassays revealed that T. rapae avoided fungal infested host habitats and that this was dependent on fungal species and density. In particular, the parasitoid avoided habitats with high densities of the more virulent fungus, M. brunneum. In addition, host density was found to be important for the attraction of T. rapae. Volatiles collected from host habitats revealed different compound profiles depending on fungal presence and density, which could explain the behavior of T. rapae. We conclude that T. rapae females may use volatile compounds to locate high densities of prey, but also compounds related to fungal presence to reduce the risk of IGP towards themselves and their offspring.Electronic supplementary materialThe online version of this article (doi:10.1007/s00442-015-3326-2) contains supplementary material, which is available to authorized users.

Passive vectoring of entomopathogenic fungus Beauveria bassiana among the wax moth Galleria mellonella larvae by the ectoparasitoid Habrobracon hebetor females

“…In evolutionary process parasitoids formed defense mechanism against the pathogenic microorganisms. Parasitoids can avoid both insects infected with entomopathogenic fungi and habitats with a high density of fungal pathogens (Rännbäck et al ., ; Cotes et al ., ). However, parasitoids can recognize infected hosts in a latter stages of diseases, but not during the initial stages (Furlong & Pell, ; Baverstock et al ., ).…”

The Potential for Decision Support Tools to Improve the Management of Root-Feeding Fly Pests of Vegetables in Western Europe

“…However, transplanting of modules in the spring may be at a time when temperatures are too low for the fungi to be effective. Studies have shown that the parasitoid T. rapae is able to locate high densities of prey (i.e., D. radicum larvae), but also avoid host habitats with high densities of the entomopathogenic fungus M. brunneum [81]. A combination of habitat management for parasitoids and inoculation with entomopathogenic fungi may be an effective integrated approach against D. radicum larvae, although there may be no additive effect [82].…”

Index of host habitat preference explored by movement‐based simulations and trap captures

“…Host habitat selection has been defined by Jaenike and Holt () “as any behaviour that causes an individual to experience a set of environmental states different from that expected to be encountered by individuals moving at the same rate randomly through the environment.” Host habitat selection has also been called host habitat location (Quilici & Rousse, ; Vet, ) or host habitat preference (HHP; Eitam & Vargas, ; Segura et al., ). Some authors refer merely to habitat selection or choice, habitat preference or host habitat (Cotes et al., ; de Meeus, Hochberg, & Renaud, ; Nosil, Crespi, Sandoval, & Kirkpatrick, ; Rausher, ; Zhao & Kang, ), and may or may not want to differentiate between hosts and habitat. Some species are mainly found on the host animal or plant while other species are commonly found in surrounding habitat and only briefly on the host.…”

“…Host habitat selection has also been called host habitat location (Quilici & Rousse, 2012;Vet, 1983) or host habitat preference (HHP; Eitam & Vargas, 2007;Segura et al, 2016). Some authors refer merely to habitat selection or choice, habitat preference or host habitat (Cotes et al, 2015;de Meeus, Hochberg, & Renaud, 1995;Nosil, Crespi, Sandoval, & Kirkpatrick, 2006;Rausher, 1984;Zhao & Kang, 2002), and may or may not want to differentiate between hosts and habitat. Some species are mainly found on the host animal or plant while other species are commonly found in surrounding habitat and only briefly on the host.…”

“…Lygus plant bugs (Miridae) disperse from less preferred cotton hosts to the preferred host alfalfa (Bancroft, 2005). Olfactory mechanisms appear to aid moths, bark beetles, parasitoid wasps and many other insects in finding and staying in host habitat by means of attraction to pheromones and host plant volatiles (Byers, 1989;Byers et al, 1985;Cotes et al, 2015;El-Sayed et al, 2008Landolt & Phillips, 1997;Quilici & Rousse, 2012;Vet, 1983;Zhao & Kang, 2002). Many insects appear to have evolved behaviour to search in a random forward direction for host habitats until finding appropriate odour of host plants or insects (Byers, 1989(Byers, , 1991(Byers, , 1999(Byers, , 2012a(Byers, , 2012bLevi−Zada et al, 2018).…”