Relative importance of infochemicals from first and second trophic level in long-range host location by the larval parasitoidCotesia glomerata

Abstract

Recently parasitoids were hypothesized to encounter a reliability-detectability problem relating to chemical stimuli from the first and second trophic level, when searching for hosts. The relative role of infochemicals originating from the host,Pieris brassicae (second trophic level), and its food plant, cabbage (first trophic level), have been investigated with respect to long-range host location by the larval parasitoidCotesia glomerata. Flight-chamber dual choice tests showed that uninfested cabbage plants are least attractive to female wasps. Host larvae and their feces were more attractive than clean plants but far less attractive than artificially damaged and herbivore-damaged plants. The plant-host complex, with host larvae actively feeding on the plant, was the most attractive odor source for the parasitoids. The data indicate that one of the solutionsC. glomerata uses to solve the reliability-detectability problem is to respond to infochemicals that are emitted from herbivore-damaged plants. Whether these infochemicals are herbivore-induced synomones that are produced by the plant remains to be demonstrated. Infochemicals emitted by the herbivore or its by-products are of little importance in the foraging behavior ofC. glomerata.

Antennal Electrophysiological Responses of Three Parasitic Wasps to Caterpillar-Induced Volatiles from Maize (Zea mays mays), Cotton (Gossypium herbaceum), and Cowpea (Vigna unguiculata)

“…The release of volatile compounds when plants are attacked by insect herbivores, and the attractiveness of such induced compounds to natural enemies, have been shown in various studies Steinberg et al, 1993;Geervliet et al, 1994;Dicke and Vet, 1998). In some systems, there are key compounds for the attraction of parasitoids, such as 6-methyl-5-hepten-2-one, which is an indicator of the presence of specific host aphids for the parasitoid, Aphidius ervi (Du et al, 1998).…”

“…Many plants attacked by herbivorous insects indirectly defend themselves by emitting semiochemicals that act as attractants for natural enemies of the attackers (Dicke and Sabelis, 1988;Turlings et al, 1990;Steinberg et al, 1993;Agelopoulos and Keller, 1994;Geervliet et al, 1994;Röse et al, 1997;Du et al, 1998;Shiojiri et al, 2000;Neveu et al, 2002). At least 12 families of plants produce volatiles in response to herbivory (Dicke, 1999).…”

Variation In Plant Volatiles and Attraction Of The ParasitoidDiadegma semiclausum(Hellén)

“…This indicates that subtle differences in volatile profiles of uninfested plants could be important in the attractivity of these plants for D. semiclausum. Brussels sprout plants damaged by hosts are more attractive for the parasitoids Cotesia glomerata, C. rubecula, and C. plutellae than artificially damaged or intact Brussels sprout plants (Steinberg et al, 1992(Steinberg et al, , 1993Blaakmeer et al, 1994;Geervliet et al, 1996;Shiojiri et al, 2000). A recent study by Ohara et al (2003) showed that D. semiclausum females were attracted by the odor blends of uninfested and infested cruciferous plants.…”

The Role of Fresh versus Old Leaf Damage in the Attraction of Parasitic Wasps to Herbivore-Induced Maize Volatiles

“…Various studies on host searching by parasitoids show that plant-provided cues are more important for the location of host habitats than odor cues from the host or host by-products (Turlings et al, 1990;Steinberg et al, 1993;McCall et al, 1993;Agelopoulos and Keller, 1994;Geervliet et al, 1994;Mattiacci et al, 1994;Takabayashi et al, 1995;Fukushima et al, 2002), but it remains largely unknown which compounds are the most crucial for the attraction.…”