Oxidative status and reproductive effort of great tits in a handicapping experiment

Father's contribution in child care matters. Using an experimental approach, we showed that handicapped great tit fathers are more likely to reduce investment in their offspring compared with control fathers. In contrast, handicapped mothers did not reduce investment in their offspring. Furthermore, cellular stress levels differed between males and females, supporting the idea that males and females follow different lifetime strategies when it comes to the trade-off between self-maintenance and reproductio

Parasites suppress immune-enhancing effect of methionine in nestling great tits

After birth, an organism needs to invest both in somatic growth and in the development of efficient immune functions to counter the effects of pathogens, and hence an investment trade-off is predicted. To explore this trade-off, we simultaneously exposed nestling great tits (Parus major) to a common ectoparasite, while stimulating immune function. Using a 2×2 experimental design, we first infested half of the nests with hen fleas (Ceratophyllus gallinae) on day 3 post-hatch and later, on day 9-13 post-hatch, and then supplemented half of the nestlings within each nest with an immuno-enhancing amino acid (methionine). We then assessed the non-specific immune response by measuring both the inflammatory response to a lipopolysaccharide (LPS) and assessing the levels of acute phase proteins (APP). In parasite-infested nestlings, methionine had a negative effect on body mass close to fledging. Methionine had an immune-enhancing effect in the absence of ectoparasites only. The inflammatory response to LPS was significantly lower in nestlings infested with fleas and was also lower in nestlings supplemented with methionine. These patterns of immune responses suggest an immunosuppressive effect of ectoparasites that could neutralise the immune-enhancing effect of methionine. Our study thus suggests that the trade-off between investment in life history traits and immune function is only partly dependent on available resources, but shows that parasites may influence this trade-off in a more complex way, by also inhibiting important physiological functions

Data from: Heterozygosity is linked to the costs of immunity in nestling great tits (Parus major)

There is growing evidence that heterozygosity–fitness correlations (HFCs) are more pronounced under harsh conditions. Empirical evidence suggests a mediating effect of parasite infestation on the occurrence of HFCs. Parasites have the potential to mediate HFCs not only by generally causing high stress levels but also by inducing resource allocation tradeoffs between the necessary investments in immunity and other costly functions. To investigate the relative importance of these two mechanisms, we manipulated growth conditions of great tit nestlings by brood size manipulation, which modifies nestling competition, and simultaneously infested broods with ectoparasites. We investigated under which treatment conditions HFCs arise and, second, whether heterozygosity is linked to tradeoff decisions between immunity and growth. We classified microsatellites as neutral or presumed functional and analyzed these effects separately. Neutral heterozygosity was positively related to the immune response to a novel antigen in parasite-free nests, but not in infested nests. For nestlings with lower heterozygosity levels, the investments in immunity under parasite pressure came at the expenses of reduced feather growth, survival, and female body condition. Functional heterozygosity was negatively related to nestling immune response regardless of the growth conditions. These contrasting effects of functional and neutral markers might indicate different underlying mechanisms causing the HFCs. Our results confirm the importance of considering marker functionality in HFC studies and indicate that parasites mediate HFCs by influencing the costs of immune defense rather than by a general increase in environmental harshness levels

Body measures and heterozygosity levels

This data set includes nestling body measures and heterozygosity levels of nestlings and rearing parents. Nest_ID: Nest of rearing, Chick_ID: Individual nestling's code, Brood_manipul: Brood size manipulation treatment, Infestation: Flea infestation, Original_brood: Brood size before manipulation treatment, HetHLm(f)_f: Functional heterozygosity of foster male (female), HetHLm(f)_n: Neutral heterozygosity of foster male (female), HetHL_f: Nestling functional heterozygosity, HetHL_n: Nestling neutral heterozygosity, Sex: Nestling sex, Weight_d15: Nestling weight 15 days after hatching, Fledged: 1=nestling successfully fledged, 0= nestling died, LPS_response: Difference in thickness measure before and after LPS-Injection, Rank: Nestling hatching rank, Body_cond: Nestling body conditio

Single locus heterozygosity

Single locus heterozygosity for all individual nestlings. 0=homozygous, 1=heterozygous

Body measures and heterozygosity levels

This data set includes nestling body measures and heterozygosity levels of nestlings and rearing parents. Nest_ID: Nest of rearing, Chick_ID: Individual nestling's code, Brood_manipul: Brood size manipulation treatment, Infestation: Flea infestation, Original_brood: Brood size before manipulation treatment, HetHLm(f)_f: Functional heterozygosity of foster male (female), HetHLm(f)_n: Neutral heterozygosity of foster male (female), HetHL_f: Nestling functional heterozygosity, HetHL_n: Nestling neutral heterozygosity, Sex: Nestling sex, Weight_d15: Nestling weight 15 days after hatching, Fledged: 1=nestling successfully fledged, 0= nestling died, LPS_response: Difference in thickness measure before and after LPS-Injection, Rank: Nestling hatching rank, Body_cond: Nestling body conditio

Prospects and challenges for the conservation of farm animal genomic resources, 2015-2025

Livestock conservation practice is changing rapidly in light of policy developments, climate change and diversifying market demands. The last decade has seen a step change in technology and analytical approaches available to define, manage and conserve Farm Animal Genomic Resources (FAnGR). However, these rapid changes pose challenges for FAnGR conservation in terms of technological continuity, analytical capacity and integrative methodologies needed to fully exploit new, multidimensional data. The final conference of the ESF Genomic Resources program aimed to address these interdisciplinary problems in an attempt to contribute to the agenda for research and policy development directions during the coming decade. By 2020, according to the Convention on Biodiversity's Aichi Target 13, signatories should ensure that "…the genetic diversity of …farmed and domesticated animals and of wild relatives …is maintained, and strategies have been developed and implemented for minimizing genetic erosion and safeguarding their genetic diversity." However, the real extent of genetic erosion is very difficult to measure using current data. Therefore, this challenging target demands better coverage, understanding and utilization of genomic and environmental data, the development of optimized ways to integrate these data with social and other sciences and policy analysis to enable more flexible, evidence-based models to underpin FAnGR conservation. At the conference, we attempted to identify the most important problems for effective livestock genomic resource conservation during the next decade. Twenty priority questions were identified that could be broadly categorized into challenges related to methodology, analytical approaches, data management and conservation. It should be acknowledged here that while the focus of our meeting was predominantly around genetics, genomics and animal science, many of the practical challenges facing conservation of genomic resources are societal in origin and are predicated on the value (e.g., socio-economic and cultural) of these resources to farmers, rural communities and society as a whole. The overall conclusion is that despite the fact that the livestock sector has been relatively well-organized in the application of genetic methodologies to date, there is still a large gap between the current state-of-the-art in the use of tools to characterize genomic resources and its application to many non-commercial and local breeds, hampering the consistent utilization of genetic and genomic data as indicators of genetic erosion and diversity. The livestock genomic sector therefore needs to make a concerted effort in the coming decade to enable to the democratization of the powerful tools that are now at its disposal, and to ensure that they are applied in the context of breed conservation as well as development