Publications by authors named "Tobias Kehl"

The market of new psychoactive substances (NPS) is characterized by a high turnover and thus provides several challenges for analytical toxicology. The analysis of urine samples often requires detailed knowledge about metabolism given that parent compounds either may be present only in small amounts or may not even be excreted. Hence, knowledge of the metabolism of NPS is a prerequisite for the development of reliable analytical methods.

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We summarise our work on male mating behaviour in the tropical butterfly , responding to the commentary provided by Nieberding and Holveck. We acknowledge that our laboratory studies are not free of shortcomings and potential caveats, though we attempted to address or highlight these within each paper. The concerns raised seem to stem mainly from different notions with respect to the proximate basis of old male mating advantage, and specifically the relative importance of male behaviour versus pheromone blend.

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Background: Intraspecific communication is of crucial importance throughout the animal kingdom and may involve a combination of visual, gustatory, olfactory and acoustic cues. Variation in male sex pheromone amount and composition may convey important information to female conspecifics, for instance on species identity or age. However, whether increased male pheromone titres are associated with fitness benefits for the female, thus indicating a role as an honest signal, is under debate.

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Old-male mating advantage has been convincingly demonstrated in Bicyclus anynana butterflies. This intriguing pattern may be explained by two alternative hypotheses: (i) an increased aggressiveness and persistence of older males during courtship, being caused by the older males' low residual reproductive value; and (ii) an active preference of females towards older males what reflects a good genes hypothesis. Against this background, we here investigate postcopulatory sexual selection by double-mating Bicyclus anynana females to older and younger males, thus allowing for sperm competition and cryptic mate choice, and by genotyping the resulting offspring.

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It is commonly assumed that holometabolic insects such as Lepidoptera rely primarily on larval storage reserves for reproduction. Recent studies though have documented a prominent role of adult-derived carbohydrates for butterfly reproduction. Moreover, a few studies have shown that adult butterflies may also benefit from adult-derived amino acids, at least when larval storage reserves are reduced.

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