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Université de Neuchâtel

Performance of leaf beetle larvae on sympatric host and non-host plants

Ballabeni, Pierluigi ; Rahier, Martine

In: Entomologia Experimentalis et Applicata, 2000, vol. 97, no. 2, p. 175-181

Studies asking the ability of insects to utilize novel host plants often use novel hosts that are allopatric with the insect population under investigation. However, since the outcomes of species interactions are often site-specific, such studies cannot tell us whether a plant would actually be used by a given insect population if the plant grew sympatrically with it. We therefore performed a...

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

Production of cardenolides versus sequestration of pyrrolizidine alkaloids in larvae of Oreina species (Coleoptera, Chrysomelidae)

Dobler, Susanne ; Rowell-Rahier, Martine

In: Journal of Chemical Ecology, 1994, vol. 20, no. 2, p. 555-568

Adult leaf beetles of the genus Oreina are known to be defended either by autogenously produced cardenolides or by pyrrolizidine alkaloids (PAs) sequestered from the food plant, or both. In this paper we analyze larvae of different Oreina species and show that the larvae contain the same defensive toxins as the adults in quantities similar to those released in the adults' secretion....

Université de Neuchâtel

Reproductive biology of viviparous and oviparous species of the leaf beetle genus Oreina

Dobler, Susanne ; Rowell-Rahier, Martine

In: Entomologia Experimentalis et Applicata, 1996, vol. 80, no. 2, p. 375-388

In five species of the genus Oreina Chevrolat (Coleoptera, Chrysomelidae) we compared the size of offspring, the fecundity of the females, the timing of offspring production and female investment over the season. Two of the species, O. elongata and O. luctuosa, laid eggs, while O. cacaliae, O. gloriosa and O. variabilis gave birth to larvae. Offspring...

Université de Neuchâtel

Physiological sources of variation in chemical defense of Oreina gloriosa (Coleoptera: Chrysomelidae)

Eggenberger, F. ; Rowell-Rahier, Martine

In: Journal of Chemical Ecology, 1993, vol. 19, no. 3, p. 395-410

The defensive secretion of the alpine chrysomelid Oreina gloriosa is a complex mixture of mainly cardenolides and tyrosine betaine. Individually sampled secretions of adult laboratory-reared and field-collected beetles were analyzed by reverse-phase HPLC; 16 secretion components were quantified. Quantities and concentrations of different components were significantly affected by the age,...

Université de Neuchâtel

Genetic component of variation in chemical defense of Oreina gloriosa (Coleoptera: Chrysomelidae)

Eggenberger, F. ; Rowell-Rahier, Martine

In: Journal of Chemical Ecology, 1992, vol. 18, no. 8, p. 1375-1387

Defensive secretions of adult Oreina gloriosa, liberated at the surface of the pronotum and elytra, contain a complex mixture of cardenolides, and ethanolamine. Proportions and concentrations of constituents determined by reverse-phase HPLC show considerable variation among individual beetles. Heritabilities of proportions of five main components were estimated by mother-offspring...

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

Sequestration, Maintenance, and Tissue Distribution of Pyrrolizidine Alkaloid N-Oxides in Larvae of Two Oreina Species

Ehmke, Adelheid ; Rahier, Martine ; Pasteels, Jacques M. ; Theuring, Claudine ; Hartmann, Thomas

In: Journal of Chemical Ecology, 1999, vol. 25, no. 10, p. 2385-2395

Oreina cacaliae and O. speciosissima are leaf beetles that, as larvae and adults, sequester pyrrolizidine alkaloid N-oxides (PAs) as defensive compounds from their host plants Adenostyles alliariae and Senecio nemorensis. As in most Oreina species, O. speciosissima is also defended by autogenously produced cardenolides (mixed defensive strategy),...

Université de Neuchâtel

Sequestration of ingested [14C]senecionine N-oxide in the exocrine defensive secretions of chrysomelid beetles

Ehmke, Adelheid ; Rowell-Rahier, Martine ; Pasteels, Jacques M. ; Hartmann, Thomas

In: Journal of Chemical Ecology, 1991, vol. 17, no. 12, p. 2367-2379

Oreina cacaliae (Chrysomelidae) sequesters in its elytral and pronotal defensive secretion the N-oxides of pyrrolizidine alkaloids (PA N-oxides) from its food plant Adenostyles alliariae (Asteraceae). [14C]Senecionine N-oxide was applied for detailed studies of PA N-oxide sequestration. An average of 11.4% of total radioactivity is taken up by...

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,...