Learning is involved in the response of parasitic wasps Aphidius ervi (Haliday) (Hymenoptera: Braconidae) to volatiles from a broad bean plant, Vicia faba (Fabaceae), infested by aphids Acyrthosiphon pisum (Harris) (Homoptera: Aphididae)

Abstract

It has been reported that volatiles from broad bean plants, Vicia faba (cv. 'the Sutton') infested by the pea aphid, Acyrthosiphon pisum, attract a specialist parasitoid Aphidius ervi, collected from populations in England, Italy and Bulgaria, which had no previous experience of the host-infested plant volatiles. Aphidius ervi collected in Hokkaido, Japan were also attracted to volatiles from host-infested broad bean plants (cv. 'Nintoku Issun') in preference to those from intact plants in a Y-tube olfactometer when the wasps were allowed to emerge on the infested plants, but wasps that had emerged in a clean Petri dish showed no significant choice between the two odor sources. When artificially exposed to the infested plant volatiles during emergence from the mummy, the wasps showed a significant preference for infested plant volatiles over those from intact plants. In further studies in a wind tunnel, significantly more wasps landed on infested plants than on intact plants when wasps were exposed to infested plant volatiles. Naïve wasps, however, did not show a higher landing response to infested plants. These data suggest that learning is required by A. ervi of the Hokkaido strain for their response to infested plant volatiles in their host searching behavior.

Exogenous application of liquid diet, previously fed upon by pea aphidsAcyrthosiphon pisum(Harris), to broad bean leaves induces volatiles attractive to the specialist parasitic waspAphidius ervi(Haliday)

“…Here, we focused on elicitors of pea aphid (Acyrthosiphon pisum) in a tritrophic system of broad bean plants, pea aphids, and parasitic wasps (Aphidius ervi). In previous studies, broad bean plants infested by pea aphids start emitting HIPVs which are attractive to A. ervi in a Y-tube olfactometer and in a wind tunnel (Du et al 1996;Powell et al 1998;Takemoto et al 2009). Aphids are known to inject saliva, which can contain candidates of elicitors.…”

“…They were kept under laboratory conditions (2092 8C, 16L8D, 50Á70 rh) on broad bean plants with A. pisum as hosts. Since A. ervi of Hokkaido strain shows no or little olfactory responses to host-infested plant without previous experience of the odor (Takemoto et al 2009), previous odor experience was conducted in the following manner. Mummies were removed from infested plants and kept in a Polyethylene terephthalate tube (6-cm diameter, 15-cm long, with the openings covered with gauze).…”

“…500 lux). The method described in Takemoto et al (2009) was applied to this study. Air was passed through activated charcoal and odor source bottles, in which either test plants or control plants were placed, to a branch of the olfactometer at the rate of 800 ml/min.…”

Wind Tunnel: a Tool to Test the Flight Response of Insects to Semiochemicals

“…The camera is placed at the downwind end, so we can record all behavioral events from the releasing site to the target. Recordings of tachinid fly (Exorista japonica) behavior were easily obtained, but the resolution of the camera was not high enough to see small insects, e.g., the braconid wasp Cotesia kariyai (Fukushima et al, 2001(Fukushima et al, , 2002Hou et al, 2005;Mandour et al, 2011) and aphid parasitoids (Takemoto et al, 2009;Fujinuma et al, 2010). To record the behavior of small insects, two cameras must be set in the tunnel, one near the releasing site and another near the target site.…”

Borago officinalis attracts the aphid parasitoid Aphidius colemani (Hymenoptera: Braconidae)

“…Aphidius colemani is a generalist parasitoid of aphids, and is registered as a biological control agent in Japan. Previous studies showed that some generalist parasitoids show a preference for volatiles from plants on which their host aphids have fed by learning volatiles (Gutiérrez-Ibáñez et al, 2007;Villagra et al, 2007;Takemoto et al, 2009). A. colemani experiences plant volatiles on the mummy surface when they emerge, and shows a preference for host plant volatiles (Storeck et al, 2000;van Emden et al, 2008).…”