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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 Fribourg

Do induced responses mediate the ecological interactions between the specialist herbivores and phytopathogens of an alpine plant?

Röder, Gregory ; Rahier, Martine ; Naisbit, Russell E.

In: PLoS ONE, 2011, vol. 6, no. 5, p. e19571

Plants are not passive victims of the myriad attackers that rely on them for nutrition. They have a suite of physical and chemical defences, and are even able to take advantage of the enemies of their enemies. These strategies are often only deployed upon attack, so may lead to indirect interactions between herbivores and phytopathogens. In this study we test for induced responses in wild...

Université de Fribourg

Discordances between phylogenetic and morphological patterns in alpine leaf beetles attest to an intricate biogeographic history of lineages in postglacial Europe

Triponez, Yann ; Buerki, Sven ; Borer, Matthias ; Naisbit, Russel E. ; Rahier, Martine ; Alvarez, Nadir

In: Molecular Ecology, 2011, vol. 20, no. 11, p. 2442–2463

Pleistocene glacial and interglacial periods have moulded the evolutionary history of European cold-adapted organisms. The role of the different mountain massifs has, however, not been accurately investigated in the case of high-altitude insect species. Here, we focus on three closely related species of non-flying leaf beetles of the genus Oreina (Coleoptera, Chrysomelidae), which are often found...

Université de Fribourg

The phylogeography of an alpine leaf beetle: Divergence within Oreina elongata spans several ice ages

Borer, Matthias ; Alvarez, Nadir ; Buerki, Sven ; Margraf, Nicolas ; Rahier, Martine ; Naisbit, Russell E.

In: Molecular Phylogenetics and Evolution, 2010, vol. 57, no. 2, p. 703-709

The genetic landscape of the European flora and fauna was shaped by the ebb and flow of populations with the shifting ice during Quaternary climate cycles. While this has been well demonstrated for lowland species, less is known about high altitude taxa. Here we analyze the phylogeography of the leaf beetle Oreina elongata from 20 populations across the Alps and Apennines. Three mitochondrial and...

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...

Université de Neuchâtel

Detoxification of pyrrolizidine alkaloids by the harvestman Mitopus morio (Phalangidae) a predator of alkaloid defended leaf beetles

Hartmann, Thomas ; Häggström, Håkan ; Theuring, Claudine ; Lindigkeit, Rainer ; Rahier, Martine

In: Chemoecology, 2003, vol. 13, no. 3, p. 123-127

The harvestman Mitopus morio (Phalangidae) is a generalist predator. It is known to prey on larvae of the chrysomelid leaf beetle Oreina cacaliae defended by plant acquired pyrrolizidine alkaloids (PAs). Tracer feeding experiments were performed to determine how harvestmen tolerate protoxic PAs. Minced meat containing either [14C]senecionine or [14C]senecionine...

Université de Neuchâtel

Mate Choice and Toxicity in Two Species of Leaf Beetles with Different Types of Chemical Defense

Labeyrie, Estelle ; Blanckenhorn, Wolf U. ; Rahier, Martine

In: Journal of Chemical Ecology, 2003, vol. 29, no. 7, p. 1665-1680

Evidence for the use of defensive compounds for sexual purposes is scarce, even though sexual selection might have some importance for the evolution of defensive traits. This study investigates the effect of defense-related traits and body size on mating success in two sister species of leaf beetle differing in their type of chemical defense. Oreina gloriosa produces autogenous...

Université de Neuchâtel

Attraction of a Leaf Bettle (Oreina cacaliae) to Damaged Host Plants

Kalberer, Nicole M. ; Rahier, Martine ; Turlings, Ted C. J.

In: Journal of Chemical Ecology, 2001, vol. 27, no. 4, p. 647-661

Early in spring, just after the snow melts, the leaf beetle Oreina cacaliae feeds on flowers of Petasites paradoxus. Later in spring they switch to their principle host plant Adenostyles alliariae. The attractiveness of short- and long-term damaged host plants was studied in a wind tunnel. The spring host P. paradoxus was more attractive to the beetles after it had...

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),...