BORNEOL AS AN ATTRACTANT FOR CYZENIS ALBICANS, A TACHINID PARASITOID OF THE WINTER MOTH, OPEROPHTERA BRUMATA L. (LEPIDOPTERA: GEOMETRIDAE)

Abstract

Volatile compounds were isolated and identified from a crude extract of garry oak, Quercus garryana, foliage which was known to be attractive to the tachinid fly Cyzenis albicans. Candidate compounds were identified by the combined use of gas chromatography–mass spectrometry, and infra-red spectroscopy. Specific oak-leaf volatiles were field-tested in 2 different years in an apple orchard. Compounds were applied singly or in combination to individual apple trees; the number of C. albicans entering the canopy of each tree was observed and the number of eggs they oviposited on foliage was estimated. Borneol was the only compound that attracted flies when compared with the other treatments, but this did not result in more fly eggs being oviposited on borneol-treated trees. None of the compounds tested resulted in a greater number of Cyzenis eggs being oviposited. A greater abundance of borneol in oak foliage than in apple foliage, and its attractiveness to C. albicans, may explain the aggregation of flies in response to feeding-damage among oak trees and the absence of this pattern among apple trees.

What determines host range in parasitoids? An analysis of a tachinid parasitoid community

“…Belshaw's (1994) analysis of literature-derived data from the Palaearctic region also failed to find elevated host ranges in tachinids with indirect reproductive strategies. This may be a consequence of depositing offspring on specific substrates (e.g., particular food-plant species), and high specificity in the cues used to locate hosts (Roland et al 1995, Mondor and Roland 1997, 1998. The association between indirect oviposition strategies and attack of gregarious hosts may partially explain the finding that host ranges of these taxa are no greater than those of direct ovipositors.…”

Oviposition behavior of the parasitoid fly, Bessa parallela (Meigen) (Diptera: Tachinidae), in the field

“…Also, E. japonica Townsend pursued crawling larvae on foot using visual cues for guidance (Yamawaki et al, 2002). In some tachinid flies, attraction to odor from healthy and damaged plants has been demonstrated (Nettles, 1980;Roth et al, 1982;Roland, 1986;Roland et al, 1989Roland et al, , 1995Mondor and Roland, 1997;Kainoh et al, 1999;Stireman, 2002). Kairomones in the host frass have been shown to induce oviposition and larviposition by tachinid flies (Hsiao et al, 1966;Roth et al, 1978;Nettles, 1982;Thompson et al, 1983;Clement et al, 1986).…”

“…Geervliet et al, 2000;Casas et al, 2004). In Tachinidae, some field researches directly observed oviposition behavior on microtype tachinids which lay incubated microtype eggs on the host plants of host insects (Roland et al, 1995;Mondor and Roland, 1997), but very few on direct-ovipositing tachinids which directly deposit eggs on/into host insects (but see López et al, 1995). Field experiments and observations with foraging parasitoids are essential to validate the conclusions from laboratory studies and to interpret differences in searching and host selection behavior of parasitoid species (Geervliet et al, 2000).…”

Host location and suitability of the armyworm larvae of Mythimna unipuncta for the tachinid parasitoid Exorista larvarum

“…In Tachinidae, attraction to herbivore-infested plants themselves or to their extracts has been demonstrated in several species (Roth et al 1978;Roland et al 1989Roland et al , 1995Mondor and Roland 1997;Kainoh et al 1999;Stireman 2002a). Our results indicate that the host-induced blends are also important for the attraction of E. larvarum.…”

“…However, the mechanisms of host selection in Tachinidae, including the role of the host-plant, remain largely unknown, as few studies have been performed on these topics. In particular, the chemical attractant of only one tachinid, Cyzenis albicans (Fallen) (a parasitoid of the winter moth Operophtera brumata L.), has been identified (Roland et al 1995). Exorista japonica Townsend, a polyphagous gregarious larval parasitoid of Lepidoptera, was more attracted to the plant/phytophage complex, consisting of larvae of the noctuid moth Mythimna separata (Walker) in the act of feeding on a maize leaf, and was less attracted to damaged plants after larvae and larval frass had been removed (Kainoh et al 1999).…”