Response of the braconid parasitoid Cotesia (=Apanteles) glomerata to volatile infochemicals: effects of bioassay set‐up, parasitoid age and experience and barometric flux

Abstract

Upon initiating a research project on the role of volatile infochemicals in the tritrophic system Cotesia (= Apanteles) glomerata (L.) ‐ Pieris brassicae (L.) ‐ cabbage, a bioassay was developed to investigate the response of C. glomerata. The bioassay should be effective in terms of high responsiveness and minimum variability and constructed through a comparative approach. Twenty seven treatments, organized in a factorial randomized block design, compared the effect of three bioassay set‐ups (glasshouse flight chamber, wind‐tunnel and Y‐tube olfactometer), three parasitoid age groups (1–2, 4–5 and 8–9 days old females), three pre‐treatment experiences (naive, damage experienced and oviposition experienced wasps) and the day‐to‐day effect on response of C. glomerata to clean cabbage (CC) and plant‐host complex (PHC) in a dual choice test. The best results with regard to the strength and consistency of response to the PHC were obtained in the glasshouse flight‐chamber by 4–5 days old female wasps with either damage or oviposition experience (94 and 90%, respectively). It is therefore recommended as a suitable bioassay for studying the role of volatile infochemicals in host‐habitat location by C. glomerata. A day‐to‐day variation in response was found in the glasshouse and wind‐tunnel. It was correlated with the direction of change in barometric pressure within the time period of the experiment, showing that steadily increasing atmospheric pressure yields a significantly higher response than steadily decreasing or fluctuating barometric flux. To control for the day effect it is suggested to conduct further experiments in a block design, having day as a block. Several aspects of the infochemical ecology of C. glomerata are discussed.

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.…”

EAG-Active Herbivore-Induced Plant Volatiles Modify Behavioral Responses and Host Attack by An Egg Parasitoid

“…Because associative learning often increases the response of parasitoids to host-related volatiles (Vet and Groenewold 1990;Turlings et al 1991;Steinberg et al 1992;Conti et al 1997;Drukker et al 2000;SantolamazzaCarbone et al 2004), we investigated the effects of experience on A. iole response to HIPVs. Specifically, we asked: (1) Do female and male A. iole antennae respond differentially to HIPVs?…”

Oviposition Response of Cotesia plutellae (Hymenoptera: Braconidae) to Sterile and Normal Diamondback Moth (Lepidoptera: Plutellidae) Larvae

“…Foraging female Cotesia glomerata (L.) are strongly attracted to cabbage plants with Pieris brassicae (L.) feeding damage (Steinberg et al 1992 There was a higher consumption of foliage by normal larvae compared with sterile larvae when larvae were allowed to pupate. This was attributed to a higher mortality rate among sterile larvae over their entire developmental period.…”