Growing large in a low grade environment: Size dependent foraging gain and niche shifts to cannibalism in Arctic char

Article Abstract:

A study on the relationship between size scaling of energy intake, total metabolic costs and levels of storage energy related to the niche shift from invertebrate feeding to cannibalism in an alpine Arctic char population is conducted. The result showed that immature individuals close to the upper size limit for positive net energy gain in the invertebrate niche had low levels of storage lipids but tended to have high mass specific growth rates implying a reallocation from reversible energy to structural growth as a strategy to transform into the size-range where the cannibalistic niche is exploited.

Norway, Physiological aspects, Food and nutrition, Energy metabolism, Predation (Biology), Bioenergetics

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Intraspecific competition and density dependence in an Ephestia kuehniella-Venturia canescens laboratory system

Article Abstract:

Mediterranean flour moths attacked in the late larval stage by parasitoids showed a change from competing for food to competition for parasite-free space. Hosts escaping parasitism tended to be small, producing reduced egg sizes and with lower fecundity, while parasitoid adult size had an inverse relationship to host density.

Moths, Parasitic insects

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Selection of Arctic charr generated by competition from brown trout

Article Abstract:

Arctic charr and brown trout appear to compete for the same resources, with data suggesting interference may limit charr growth. For individuals, there appears to be selection against Actic charr with long fins and large heads as well as against those feeding on zoobenthos rather than zooplankton.

Brown trout

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