Vignette d'image

Turlings, Ted

Nom
Turlings, Ted
Affiliation principale
Fonction
Professeur.e ordinaire
Email
ted.turlings@unine.ch
Identifiants
https://libra.unine.ch/handle/123456789/330
_
0000-0002-8315-785X

Résultat de la recherche

Filtres

5
5
5
Réinitialiser les filtres

Paramètres

Voici les éléments 1 - 5 sur 5
  • Publication
    Accès libre
    How Caterpillar-Damaged Plants Protect Themselves by Attracting Parasitic Wasps
    (1995)
    Turlings, Ted 
    ;
    Loughrin, John H.
    ;
    McCall, Philip J.
    ;
    Röse, Ursula S. R.
    ;
    Lewis, W. Joe
    ;
    Tumlinson, James H.
    Parasitic and predatory arthropods often prevent plants from being severely damaged by killing herbivores as they feed on the plants. Recent studies show that a variety of plants, when injured by herbivores, emit chemical signals that guide natural enemies to the herbivores. It is unlikely that herbivore-damaged plants initiate the production of chemicals solely to attract parasitoids and predators. The signaling role probably evolved secondarily from plant responses that produce toxins and deterrents against herbivores and antibiotics against pathogens. To effectively function as signals for natural enemies, the emitted volatiles should be clearly distinguishable from background odors, specific for prey or host species that feed on the plant, and emitted at times when the natural enemies forage. Our studies on the phenomena of herbivore-induced emissions of volatiles in corn and cotton plants and studies conducted by others indicate that (i) the clarity of the volatile signals is high, as they are unique for herbivore damage, produced in relatively large amounts, and easily distinguishable from background odors; (ii) specificity is limited when different herbivores feed on the same plant species but high as far as odors emitted by different plant species and genotypes are concerned; (iii) the signals are timed so that they are mainly released during the daytime, when natural enemies tend to forage, and they wane slowly after herbivory stops.
  • Publication
    Accès libre
    Role of plant volatiles in host location by the specialist parasitoid Microplitis croceipes cresson (Braconidae: Hymenoptera)
    (1993)
    McCall, Philip J.
    ;
    Turlings, Ted 
    ;
    Lewis, W. Joe
    ;
    Tumlinson, James H.
    A study was conducted to determine the primary source of volatile cues within the plant-host complex used by hostseeking freeflying female Microplitis cro-ceipesCresson in flight tunnel bioassays. In single-source and two-choice tests, using wasps given an oviposition experience on either cotton (Gossypium hirsutum) or cowpea (Vigna unguiculata) seedlings damaged by corn earworm (CEW; Helicoverpa zea Boddie), the damaged seedlings were significantly more attractive than the CEW frass, which was in turn more attractive than the larvae themselves. In a series of two-choice wind-tunnel tests, the discriminatory ability of the wasps was examined, following various oviposition experiences. Significantly more wasps flew to plants with old damage than to plants with fresh damage, regardless of whether they had experience on fresh or old damage. In a comparison of plant species, wasps with only one experience on either hostdamaged cotton or host-damaged cowpea were unable to distinguish between them, and showed no preference for either plant, whereas wasps with multiple experiences on a particular plant preferentially flew to that plant in the choice test. In comparing hosts with nonhosts, wasps successfully learned to distinguish CEW from beet armyworm (BAW; Spodoptera exigua) on cotton but were unable to distinguish CEW from either BAW or cabbage looper (Trichoplusia ni) on cowpea. The results show the important role played by plant volatiles in the location of hosts by M. croceipesand indicate the wasps limitations in discriminating among the various odors. The ecological advantages and disadvantages of this behavior are discussed.
  • Publication
    Accès libre
    Learning of host-finding cues by hymenopterous parasitoids
    (1993)
    Turlings, Ted 
    ;
    Wäckers, Felix L.
    ;
    Vet, Louise E. M.
    ;
    Lewis, W. Joe
    ;
    Tumlinson, James H.
  • Publication
    Accès libre
    Isolation and identification of allelochemicals that attract the larval parasitoid, Cotesia marginiventris (Cresson), to the microhabitat of one of its hosts
    (1991)
    Turlings, Ted 
    ;
    Tumlinson, James H.
    ;
    Heath, Robert R.
    ;
    Proveaux, Adron T.
    ;
    Doolittle, Robert E.
    Volatiles released from corn seedlings on which beet armyworm larvae were feeding were attractive to females of the parasitoid, Cotesia marginiventris (Cresson), in flight tunnel bioassays. Analyses of the collected volatiles revealed the consistent presence of 11 compounds in significant amounts. They were: (Z)-3-hexenal, (E)-2-hexenal, (Z)-3-hexen-1-ol, (Z)- 3-hexen-1-yl acetate, linalool, (3E)-4,8-dimethyl-1,3,7-nonatriene, indole, α-trans-bergamotene, (E)-β-farnesene, (E)-nerolidol, and (3E,7E)-4,8,12-trimethyl-1, 3,7,ll-tridecatetraene. A synthetic blend of all 11 compounds was slightly less attractive to parasitoid females than an equivalent natural blend. However, preflight experience with the synthetic blend instead of experience with a regular plant-host complex significantly improved the response to the synthetic blend. Our results suggest that C. marginiventris females, in their search for hosts, use a blend of airborne semiochemicals emitted by plants on which their hosts feed. The response to a particular odor blend dramatically increases after a parasitoid experiences it in association with contacting host by-products.
  • Publication
    Accès libre
    How contact foraging experiences affect preferences for host-related odors in the larval parasitoid Cotesia marginiventris (Cresson) (Hymenoptera: Braconidae)
    (1990)
    Turlings, Ted 
    ;
    Scheepmaker, J. W. A.
    ;
    Vet, Louise E. M.
    ;
    Tumlinson, James H.
    ;
    Lewis, W. Joe
    Responses of individual females of the parasitoid Cotesia marginiventris to the odors of four different complexes of host larvae feeding on leaves were observed in a four-arm olfactometer. The plant-host complexes were composed of fall armyworm (FAW) larvae or cabbage looper (CL) larvae feeding on either corn or cotton seedlings. Prior to testing, each female was given a brief foraging experience on a plant-host complex and was then exposed to the odors of the same complex in the olfactometer. The experienced females responded to familiar odors in a dose-related manner, and these responses were virtually identical to all four complexes. Preferences for the odors of one of two plant-host complexes were tested in dual choice situations. Generally, FAW odors were preferred over CL odors and corn odors over cotton odors. A short foraging experience significantly affected the females' odor preferences in favor of the odors released by the experienced complex. Additional experiments revealed that neither longer bouts of experience nor bouts that included ovipositions resulted in a stronger change in preference. Experience affected preference in combinations where only the host species was varied as well as in combinations where only the plant species was varied. The results, therefore, strongly indicate that both the plants and the hosts somehow are involved in the production and/or release of the semiochemicals that attract C. marginiventris.