BODY SIZE AND IMMUNE DEFENSE OF NESTLING BLUE TITS (CYANISTES CAERULEUS) IN RESPONSE TO MANIPULATION OF ECTOPARASITES AND FOOD SUPPLY

Jon Brommer, Natalia Pitala, Heli Siitari, Edward Kluen, Lars Gustafsson

    Research output: Contribution to journalArticleScientificpeer-review

    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 (tail and wing length) and hematocrit were reduced by the presence of Hen Fleas,
    indicating negative effects on nestling development. In comparison to the control nestlings, food-supplemented nestlings aged 16 days
    were larger (tarsus, residual body mass), but only in reduced-infestation nests (interaction between both treatments). Body size of fed
    male offspring increased in relation to that of females, but only in the absence of ectoparasites. We hypothesized that supplemented
    resources are allocated to immune defense when ectoparasites are present, but humoral immune function (total immunoglobulin
    concentration) and cell-mediated immune defense (phytohemagglutinin response) were not affected by either treatment. Either the
    nestlings allocated additional resources away from growth (into an unknown developmental component) when parasites were abundant,
    or the ectoparasites preferentially fed on supplementary-fed host nestlings and thereby equalized the development of soma and immune
    defense of nestlings despite provision of additional resources. Received 17 December 2010, accepted 12 March 2011
    Original languageEnglish
    JournalThe Auk
    Volume128
    Issue number3
    Pages (from-to)556-563
    Number of pages8
    ISSN0004-8038
    DOIs
    Publication statusPublished - Mar 2011
    MoE publication typeA1 Journal article-refereed

    Fields of Science

    • 1181 Ecology, evolutionary biology
    • Ecology of host-parasite relationships

    Cite this