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Université de Neuchâtel

Molecular analysis of the gut contents of Harmonia axyridis (Coleoptera: Coccinellidae) as a method for detecting intra-guild predation by this species on aphidophagous predators other than coccinellids

Ingels, Brecht ; Aeby, Alexandre ; Hautier, Louis ; Van Leeuwen, Thomas ; De Clerc, Patrick

In: European Journal of Entomology, 2013, vol. 110, no. 4, p. 567-576

Several studies have demonstrated that the invasive ladybird Harmonia axyridis is a strong intra-guild predator of native species of ladybird. Laboratory studies have shown that H. axyridis can be an intra-guild predator of aphid predators other than coccinellids, including the hoverfly Episyrphus balteatus and lacewing Chrysoperla carnea. However, little is known about...

Université de Neuchâtel

Female polyandry affects their sons' reproductive success in the red flour beetle Tribolium castaneum

Bernasconi, Giorgina ; Keller, Laurent

In: Journal of Evolutionary Biology, 2001, vol. 14, no. 1, p. 186-193

A potential benefit to females mating with multiple males is the increased probability that their sons will inherit traits enhancing their pre- or post-mating ability to obtain fertilizations. We allowed red flour beetle (Tribolium castaneum) females to mate on three consecutive days either repeatedly to the same male or to three different males. This procedure was carried out in 20...

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

Genetic structure of leaf-beetles populations: microgeographic and sexual differentiation in Oreina cacaliae and O. speciosissima

Rowell-Rahier, Martine

In: Entomologia Experimentalis et Applicata, 1992, vol. 65, no. 3, p. 247-257

We used F-statistics to quantify the population structure of two sympatric species of leaf beetles, Oreina cacaliae and O. speciosissima (Chrysomelinae, Coleoptera), which share the same microhabitat since they feed on the same herbaceous host plants. We measured genetic differentiation at six allozyme loci 1) among populations separated by relatively small distances (40 to...

Université de Neuchâtel

Economics of chemical defense in chrysomelinae

Rowell-Rahier, Martine ; Pasteels, Jacques M.

In: Journal of Chemical Ecology, 1986, vol. 12, no. 5, p. 1189-1203

Chemical defense in chrysomelid larvae (subtribe Chrysomelina and Phyllodectina) is reviewed. Most species secrete autogenous monoterpenes. The diversity of their secretion is interpreted as a mechanism to reduce adaptation by predacious arthropods. The consequences of a host plant shift to the Salicacae are explored. Salicin from these host plants is used as a precursor for the salicylaldehyde...

Université de Neuchâtel

Toxins in chrysomelid beetles : Possible evolutionary sequence from de novo synthesis to derivation from food-plant chemicals

Pasteels, Jacques M. ; Duffey, S. ; Rowell-Rahier, Martine

In: Journal of Chemical Ecology, 1990, vol. 16, no. 1, p. 211-222

In the Chrysomelinae, it appears that de novo synthesis of chemicals for defense is the primitive state, and the sequestration of plant chemicals for defense the derived state. The derived state evolved through both the morphological and biochemical preadaptiveness of the homologous defensive glands. In the adults, we discuss one unique case of sequestration in exocrine defensive glands of...

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

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,...