DOI: 10.5061/dryad.9qr0401
title: Data from: Natural selection on antihelminth antibodies in a wild mammal population

description: An effective immune response is expected to confer fitness benefits
 through improved resistance to parasites but also energetic costs which
 negatively impact fitness-related traits such as reproduction. These
 fitness costs and benefits of an immune response are likely to depend on
 host age, sex, and levels of parasite exposure. Few studies have examined
 the full extent to which patterns of natural selection on immune
 phenotypes vary across demographic groups and environments in the wild.
 Here, we assessed natural selection on plasma levels of three functionally
 distinct isotypes (IgA, IgE and IgG) of antibodies against a prevalent
 nematode parasite measured in a wild Soay sheep population over 25 years.
 We found little support for environment-dependent selection or
 reproductive costs. However, antibody levels were negatively associated
 with parasite egg counts and positively associated with subsequent
 survival, albeit in a highly age- and isotype-dependent manner. Raised
 levels of anti-parasite IgA best predicted reduced egg counts but this did
 not predict survival in lambs, whilst in adult females increased
 anti-parasite IgG predicted reduced egg counts and improved survival. Our
 results highlight the potential importance of age-dependent selection on
 immune phenotypes in nature, and that patterns of selection can vary even
 amongst functionally-related immune markers.
description: #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~# SOAY SHEEP PROJECT DATA REUSE: #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~# The attached file(s) contain data derived from the long-term field project monitoring individual Soay sheep on St Kilda and their environment. This is a request to please let us know if you use them. Several people have spent the best part of their careers collecting the data. If you plan to analyse the data, there are a number of reasons why it would be very helpful if you could contact Dan Nussey (dan.nussey@ed.ac.uk) before doing so. [NB. If you are interested in analysing the detailed project data in any depth you may find it helpful to have our full relational database rather than the file(s) available here.  If so, then we have a simple process for bringing you onto the project as a collaborator.] 1) The data can be subject to change due to updates in the pedigree, merging of records, occasional errors and so on. 2) The data are complex and workers who do not know the study system may benefit from advice when interpreting it. 3) At any one time a number of people within the existing project collaboration are analysing data from this project. Someone else may already be conducting the analysis you have in mind and it is desirable to prevent duplication of effort. 4) In order to maintain funding for the project(s), every few years we have to write proposals for original analyses to funding agencies. It is therefore very helpful for those running the project to know what data analyses are in progress. 5) Sheep identifiers may vary relative to other data archives from papers using the Soay sheep data. #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~#
description: This data was collected as part of the long term individual based
 study on the Soay sheep of St Kilda in Scotland. The full methods on how
 data was collected and processed is included in the main article
 associated with this dataset (https://doi.org/10.1086/700115): Natural selection on antihelminth antibodies in a wild mammal population A. M. Sparks, K. Watt, R. Sinclair, J. G. Pilkington, J. M. Pemberton, S. E. Johnston, T. N. McNeilly, D. H. Nussey Please see the README files for descriptions of the columns in the dataset and data usage notes.