Domestication effects on immune response: comparison of cell-mediated immune competence in wild and domesticated Bengalese finch

Abstract

Domesticated Bengalese finch (Lonchura striata var. domestica) lack natural selection pressures and consequently have more complex songs and altered behavioural and psychological traits when compared to their wild ancestor, the white-rumpud munia (Lonchura striata). Clarifying the sexual traits and life history trade-offs in Bengal finches will be help to improve our understanding of the evolution of complex songs and domesticated traits. Here, we have assessed the immune competence of the Bengalese finch and the white-rumped munia using phytohemagglutinin (PHA) tests to create an index of cell-mediated immune responses. We found that the Bengalese finch had a significantly larger immunocompetence than the white-rumped munia, indicating that they devote more resources to both immunity and reproduction. Thus, there is no trade-off but a positive relationship between immunocompetence and reproductive traits, which may be related to the release from natural selection pressures. These results will be useful in understanding the mechanisms by which domestication-induced changes due to a lack of natural selection pressure affect behavioural and physiological changes.