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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

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  • Publication
    Métadonnées seulement
  • Publication
    Métadonnées seulement
    Lydella thompsoni Herting (Dipt., Tachinidae), a parasitoid of the European corn borer, Ostrinia nubilalis Hbn. (Lep., Pyralidae) in Slovakia, Czech Republic and south-western Poland
    (1999)
    Cagan, L
    ;
    Turlings, Ted 
    ;
    Bokor, P
    ;
    Dorn, Silvia
    This paper shows that, within Central Europe, parasitism of the European corn borer (ECB) by the tachinid parasitoid, Lydella thompsoni (LT) increased from 0.47 to 1.49% in south-western Poland (51 degrees 03'N), to 4.31-21.95% in eastern Slovakia (48 degrees 20'N). The synchrony between the parasitoid LT and its primary host: the ECB, was studied in Central Europe under conditions where the host is univoltine, but the parasitoid is bivoltine. A cumulated total of more than 400 LT was field-collected from overwintering ECB larvae. The parasitoid hibernated as larva inside the host. Pupation started in the second half of the following March and 50% of pupation was surpassed in the first half of April. The first parasitoid adults emerged at the end of April and the majority at the beginning of May. Development threshold temperatures for 50% pupation was determined to be 2.7 degrees C, and for 50% adult emergence 5.0 degrees C; the respective thermal constants were 178.8-179.8 and 237.7-251.8 Celsius degree-days. Emerged adults did not parasitize overwintered ECB larvae in spring, hence there must be an alternate host for the first generation of LT in areas of univoltine life cycle of the ECB. Parasitization of the ECB larvae by LT continued until the end of July. The first parasitoid adults from this second generation emerged in the second half of August. By the end of the season, nearly one-third of LT adults had emerged. The rest of this generation apparently overwintered in the larval stage.
  • Publication
    Métadonnées seulement
    The induction of volatile emissions in maize by three herbivore species with different feeding habits: Possible consequences for their natural enemies
    (: Academic Press Inc, 1998)
    Turlings, Ted 
    ;
    Bernasconi, Marco
    ;
    Bertossa, Rinaldo
    ;
    Bigler, Franz
    ;
    Caloz, Genevieve
    ;
    Dorn, Silvia
    In order to find their prey natural enemies of herbivores often make effective use of plant volatiles that are emitted by plants on which the herbivores have been feeding. The phenomenon of herbivore-induced emissions of attractants has been well investigated for mite-plant interactions and for interactions between leaf feeding caterpillars and plants. Herbivore-induced emissions of chemical signals appear to be common in plants, but little is known about induction by herbivores that have different feeding habits. We obtained more knowledge on this by comparing the volatile emissions induced in maize plants by a folivorous caterpillar (Spodoptera littoralis), a stemborer (Ostrinia nubilalis), and an aphid (Rhopalosiphum maidis). As controls we also measured the emissions of healthy, undamaged plants and plants that were mechanically damaged and then treated with caterpillar regurgitate. Volatiles were collected twice daily for 2 h over a 3-day period after initial infestation or mechanical damage. Quantitatively, the plants infested with S. littoralis emitted by far the most. Their emissions started several hours after initial damage, lasted for the 3 days, and were the highest on the third day. The volatile profile was the same for the regurgitate-treated plants, but here the emissions dropped rapidly after the first day. The plants infested by O. nubilalis emitted the same blend of volatiles, but in much lower quantities, In addition to the known induced maize volatiles, the Ostrinia-damaged plants emitted some highly volatile, still unidentified compounds, which may be specific for the frass of this insect or emitted from the damaged plant stem. The aphids induced no measurable emissions of volatiles in the maize, even after heavy infestation. This is perhaps because several aphids, including R. maidis, barely damage the plant cells, and may not trigger a plant response. These findings suggest that induction of volatiles is the result of cell tissue damage, particularly to the leaves of the plant. This should have consequences also for the search strategies employed by the natural enemies of the respective herbivores, It can be expected that enemies of stemborers use some highly volatile compounds in addition to the known induced compounds. Natural enemies of some aphids may have to resort to other foraging cues, as the plant appears to provide them with no or very little olfactory information. (C) 1998 Academic Press.
  • Publication
    Métadonnées seulement
    Chemically-mediated attraction of three parasitoid species to mealybug-infested cassava leaves
    (1997)
    Bertschy, Catherine
    ;
    Turlings, Ted 
    ;
    Bellotti, Anthony
    ;
    Dorn, Silvia
    We investigated whether cassava plants that are infested by the cassava mealybug, Phenacoccus herreni (Pseudococcidae, Sternorrhyncha), emit attractants for the encyrtid parasitoids Aenasius vexans Kerrich, Apoanagyrus (Epidinocarsis) diversicornis Howard, and Acerophagus coccois Smith. Bioassays with a Y-tube olfactometer showed for all three species that female wasps were most responsive and selective when they were 1.5 to 2.5 days old. Females of these age groups were used to test their ability to distinguish between the odor of plants with and without mealybugs. The wasps were offered choices between infested cassava leaves vs. healthy ones, infested leaves vs. clean air, and healthy leaves vs. clean air. A. vexans and A. diversicornis were strongly attracted to infested leaves and preferred these over healthy ones. In contrast,A. coccois was significantly attracted to either healthy or infested leaves, and did not distinguish between the two. The results suggest that A. coccois, which has the broadest known host range of the three, may be responsive only to general plant odors, while A. vexans and A. diversicornis respond more specifically to odors associated with mealybug infestation.
  • Publication
    Métadonnées seulement
    Volatiles emitted by apple fruitlets infested by larvae of the European apple sawfly
    (1996)
    Boeve, Jean-Luc
    ;
    Lengwiler, Urs
    ;
    Tollsten, Lars
    ;
    Dorn, Silvia
    ;
    Turlings, Ted 
    The effect of infestation by larvae of the European apple sawfly (Hoplocampa testudinea) on the emission of volatiles from apple fruitlets was investigated. Healthy apples emitted a blend of terpenoids and a few aromatic and short aliphatic compounds. Infested apples emitted the same compounds as healthy apples. However, trans,trans-alpha-farnesene, trans-beta-ocimene and another terpenoid were emitted in significantly larger amounts, whereas the other volatiles showed no quantitative change. The results were obtained with picked apples and could be confirmed in the field with single apples left on the tree. Several non-terpenoid volatiles emanated from the frass and from epidermal glands of the sawfly larvae. The possible ecological significance of the increased emission of terpenoids by infested apples is discussed with reference to a parasitic wasp that attacks the sawfly larvae.