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Université de Fribourg

An early suitability assessment of two exotic Ophraella species (Coleoptera: Chrysomelidae) for biological control of invasive ragweed in Europe

E.Lommen, Suzanne T. ; Jolidon, Emilien F. ; Sun, Yan ; Eduardo, José I. Bustamante ; Müller-Schärer, Heinz

In: European Journal of Entomology, 2017, vol. 114, no. 1, p. 160–169

Classical biological control is an important means of managing the increasing threat of invasive plants. It constitutes the introduction of natural enemies from the native range of the target plant into the invaded area. This method may be the only cost-effective solution to control the rapidly expanding common ragweed, Ambrosia artemisiifolia, in non-crop habitats in Europe. Therefore,...

Université de Neuchâtel

Colour polymorphism in the leaf beetle genus 'Oreina'

Van Noort, Tom ; Benrey, Betty (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2013.

This dissertation investigates the maintenance of colour polymorphism in the leaf beetle genus Oreina CHEVROLAT (Coleoptera; Chrysomelidae). The remarkable colour variation in this seemingly aposematic and chemically defended genus forms a paradox with current scientific views concerning predator learning and mimicry. Using a variety of approaches we explore the selective forces that...

Université de Fribourg

Positive frequency-dependent selection on warning color in alpine leaf beetles

Borer, Matthias ; Noort, Tom Van ; Rahier, Martine ; Naisbit, Russell E.

In: Evolution, 2010, vol. 64, no. 12, p. 3629–3633

Müller's theory of warning color and mimicry, despite forming a textbook example of frequency-dependent selection, has rarely been demonstrated in the wild. This may be largely due to the practical and statistical difficulties of measuring natural selection on mobile prey species. Here we demonstrate that this selection acts in alpine beetle communities by using tethered beetles exposed to...

Université de Neuchâtel

Comparative susceptibility of larval instars and pupae of the western corn rootworm to infection by three entomopathogenic nematodes

Kurtz, B. ; Hiltpold, Ivan ; Turlings, Ted C. J. ; Kuhlmann, Ulrich ; Toepfer, Stefan

In: BioControl, 2009, vol. 54, no. 2, p. 255-262

As a first step towards the development of an ecologically rational control strategy against western corn rootworm (WCR; Diabrotica virgifera virgifera LeConte, Coleoptera: Chrysomelidae) in Europe, we compared the susceptibility of the soil living larvae and pupae of this maize pest to infection by three entomopathogenic nematode (EPN) species. In laboratory assays using sand-filled...

Université de Neuchâtel

Production of cardenolides in different life stages of the chrysomelid beetle Oreina gloriosa

Eggenberger, F. ; Rowell-Rahier, Martine

In: Journal of Insect Physiology, 1993, vol. 39, no. 9, p. 751-759

Cardenolide production in larval, pupal, and adult leaf beetles Oreina gloriosa (Coleoptera: Chrysomelidae) is compared. Significantly different levels of cardenolides were found in the various developmental stages of this species: early and late fourth-instar larvae (14 and 19 nmol, respectively), pupae (10 nmol), 1-day-old imagos (8 nmol). The developmental effects on individual...

Université de Neuchâtel

Biochemical strategy of sequestration of pyrrolizidine alkaloids by adults and larvae of chrysomelid leaf beetles

Hartmann, Thomas ; Theuring, Claudine ; Schmidt, Jürgen ; Rahier, Martine ; Pasteels, Jacques M.

In: Journal of Insect Physiology, 1999, vol. 45, no. 12, p. 1085-1095

Tracer feeding experiments with 14C-labeled senecionine and senecionine N-oxide were carried out to identify the biochemical mechanisms of pyrrolizidine alkaloid sequestration in the alkaloid-adapted leaf beetle Oreina cacaliae (Chrysomelidae). The taxonomically closely related mint beetle (Chrysolina coerulans) which in its life history never faces pyrrolizidine...