0000000000401034
AUTHOR
Natalia Pitala
The effects of experimentally manipulated yolk androgens on growth and immune function of male and female nestling collared flycatchers Ficedula albicollis
Hormone-mediated maternal effects may be an important mechanism for adjusting offspring phenotype to particular requirements of the environment. We manipulated the levels of testosterone and androstenedione in the yolk of collared flycatcher Ficedula albicollis eggs to investigate the effects of pre-natal exposure to androgens on growth and immune function. Androgen treatment tended to reduce the growth of males, and enhance the growth of females, as indicated by significant interaction between sex and androgen treatment. Cellular immune function was not affected by androgen treatment or sex. Survival of nestlings until fledging was not related to androgen treatment. Our results indicate th…
Body Size and Immune Defense of Nestling Blue Tits (Cyanistes caeruleus) in Response to Manipulation of Ectoparasites and Food Supply
ABSTRACT. A developing organism faces a dilemma: whether to allocate available resources to building its body structures (growth) or to the development of its immune system. The outcome of this tradeoff is likely to be modified by parasites. We manipulated the abundance of ectoparasitic Hen Fleas (Ceratophyllus gallinae) on nestling Blue Tits (Cyanistes caeruleus) by microwaving nests and subsequently adding 200 Hen Fleas (15 infested nests) or not (16 reduced-infestation nests). In addition, we manipulated the host nestlings' food resources by supplementary feeding 10–15% of daily energy needs to half the nestlings in a nest during the key developmental period (days 2–12). Feather growth (…
Long-term fitness consequences of high yolk androgen levels: sons pay the costs
Summary 1. Early growth conditions, for example hormonal environment during embryonic development, may have long-lasting effects on behaviour and phenotype, with subsequent fitness consequences. Yolk androgens have been shown to affect various offspring traits in the short-term, but fitness consequences for either offspring or parents, a prerequisite for studying the adaptiveness of this maternal effect, are poorly known in the wild. 2. We experimentally elevated yolk androgen levels of whole clutches in a wild population of collared flycatchers (Ficedula albicollis) and investigated the long-term effects of yolk androgens on offspring local recruitment, parental return rate, and timing and…
Low but contrasting neutral genetic differentiation shaped by winter temperature in European great tits.
Gene flow is usually thought to reduce genetic divergence and impede local adaptation by homogenising gene pools between populations. However, evidence for local adaptation and phenotypic differentiation in highly mobile species, experiencing high levels of gene flow, is emerging. Assessing population genetic structure at different spatial scales is thus a crucial step towards understanding mechanisms underlying intraspecific differentiation and diversification. Here, we studied the population genetic structure of a highly mobile species - the great tit Parus major - at different spatial scales. We analysed 884 individuals from 30 sites across Europe including 10 close-by sites (< 50 km), u…
Costs and Benefits of Experimentally Induced Changes in the Allocation of Growth versus Immune Function under Differential Exposure to Ectoparasites
Background Ecological immunology has focused on the costs of investment in immunocompetence. However, understanding optimal resource allocation to immune defence requires also identification of its benefits, which are likely to occur only when parasites are abundant. Methodology We manipulated the abundance of parasitic hen fleas in blue tit (Cyanistes caeruleus) nests, and supplemented their hosts, the nestlings, with methionine (a sulphur amino acid enhancing cell-mediated immunity) during day 3–6. We found a significant interaction between these two experimental factors on the development of immune defences and growth rates. Only in parasitized nests did methionine supplementation boost …
Data from: Low but contrasting neutral genetic differentiation shaped by winter temperature in European great tits
Gene flow is usually thought to reduce genetic divergence and impede local adaptation by homogenising gene pools between populations. However, evidence for local adaptation and phenotypic differentiation in highly mobile species, experiencing high levels of gene flow, is emerging. Assessing population genetic structure at different spatial scales is thus a crucial step towards understanding mechanisms underlying intraspecific differentiation and diversification. Here, we studied the population genetic structure of a highly mobile species – the great tit Parus major – at different spatial scales. We analysed 884 individuals from 30 sites across Europe including 10 close-by sites (< 50 km)…
Costs and benefits of experimentally induced changes in the allocation of growth versus immune function under differential exposure to ectoparasites.
Background: Ecological immunology has focused on the costs of investment in immunocompetence. However, understanding optimal resource allocation to immune defence requires also identification of its benefits, which are likely to occur only when parasites are abundant. Methodology: We manipulated the abundance of parasitic hen fleas in blue tit (Cyanistes caeruleus) nests, and supplemented their hosts, the nestlings, with methionine (a sulphur amino acid enhancing cell-mediated immunity) during day 3–6. We found a significant interaction between these two experimental factors on the development of immune defences and growth rates. Only in parasitized nests did methionine supplementation boos…