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Physiological Stress Mediates the Honesty of Social Signals
Background Extravagant ornaments used as social signals evolved to advertise their bearers' quality. The Immunocompetence Handicap Hypothesis proposes that testosterone-dependent ornaments reliablyExpand
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Testosterone, immunocompetence, and honest sexual signaling in male red grouse
The expression of sexual ornaments has been suggested to reliably indicate individual quality, such as the ability to cope with parasites and diseases. The Immunocompetence Handicap Hypothesis (IHH)Expand
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Cell-mediated immune activation rapidly decreases plasma carotenoids but does not affect oxidative stress in red-legged partridges (Alectoris rufa)
SUMMARY In animals yellow-orange-red sexual traits pigmented by carotenoids have been suggested to act as signals of current health. Because carotenoids have important physiological functions,Expand
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Physiological stress links parasites to carotenoid-based colour signals.
Vertebrates commonly use carotenoid-based traits as social signals. These can reliably advertise current nutritional status and health because carotenoids must be acquired through the diet and theirExpand
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Testing the interactive effects of testosterone and parasites on carotenoid-based ornamentation in a wild bird.
Testosterone underlies the expression of most secondary sexual traits, playing a key role in sexual selection. However, high levels might be associated with physiological costs, such asExpand
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Experimentally increased aggressiveness reduces population kin structure and subsequent recruitment in red grouse Lagopus lagopus scoticus
Summary 1. According to the ‘territorial behaviour’ hypothesis, red grouse population cycles are caused by delayed density-dependent changes in male aggressiveness influencing recruitment. TheseExpand
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Density dependence in a recovering osprey population: demographic and behavioural processes.
1. Understanding how density-dependent and independent processes influence demographic parameters, and hence regulate population size, is fundamental within population ecology. We investigatedExpand
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Experimental exposure of red-legged partridges (Alectoris rufa) to seeds coated with imidacloprid, thiram and difenoconazole
Pesticide coated seeds are commonly used in agriculture, and may be an important source of food for some birds in times of scarcity, as well as a route of pesticide ingestion. We tested the lethalExpand
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Imidacloprid-treated seed ingestion has lethal effect on adult partridges and reduces both breeding investment and offspring immunity.
The ingestion of imidacloprid treated seeds by farmland birds may result in exposure to toxic amounts of this insecticide. Here we report on the effects that the exposure to the recommendedExpand
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Testing the role of parasites in driving the cyclic population dynamics of a gamebird.
The role of parasites in regulating populations has been the subject of debate. We tested whether parasites caused population cycles in red grouse by manipulating parasite intensities in four, pairedExpand
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