Immunoglobulin level and infection intensity influence how malaria-infected collared flycatchers respond to brood size manipulation

• 1.The existence of a trade-off between investment in reproduction and immune function is well-established in many species. However, variation in the underlying physiological allocation strategies, which is what selection operates on, remains largely unexplored.2.We investigated how haemosporidian infection influenced stress hormone level and ability to increase parental effort in female collared flycatchers (Ficedula albicollis). We especially focused on how estimates of investment in humoral immune response and level of parasitemia influenced subsequent parental investment (i.e. offspring provisioning and offspring mass).3.To achieve these goals, we combined a brood size manipulation experiment with nested- and quantitative PCR methods to establish infection status and intensity. In addition, we quantified immunoglobulin Y (IgY) and stress protein levels.4. Malaria-infected females reared enlarged broods with lower mass but there was large variation in their response to the experiment. Only infected females with low IgY levels decreased their relative provisioning rate and there was a positive relationship between the intensity of infection and total brood mass.5. Our study implies that malaria-infected flycatchers experience a trade-off between keeping their infection at bay (i.e. low level of parasitemia) and responding to increased offspring demands (i.e. high offspring mass in enlarged broods). However, relatively immunocompetent individuals (i.e. individuals with high IgY levels) did not compromise their parental care suggesting that the main cost of raising the immune response does not lay in antibody production.

Ämnesord

NATURVETENSKAP  -- Biologi -- Ekologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Ecology (hsv//eng)

Nyckelord

Avian malaria

Haemoproteus

life-history strategy

parental effort

Plasmodium

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)