Food limitation constrains host immune responses to nematode infections.
Trade-offs in the allocation of finite-energy resources among immunological defences and other physiological processes are believed to influence infection risk and disease severity in food-limited wildlife populations. However, this prediction has received little experimental investigation. Here we test the hypothesis that food limitation impairs the ability of wild field voles (Microtus agrestis) to mount an immune response against parasite infections. We conducted a replicated experiment on vole populations maintained in large outdoor enclosures during boreal winter, using food supplementation and anthelmintic treatment of intestinal nematodes. Innate immune responses against intestinal parasite infections were compared between food-supplemented and non-supplemented voles. Voles with high food availability mounted stronger immune responses against intestinal nematode infections than food-limited voles. No food effects were seen in immune responses to intracellular coccidian parasites, possibly owing to their ability to avoid activation of innate immune pathways. Our findings demonstrate that food availability constrains vole immune responses against nematode infections, and support the concept that spatio-temporal heterogeneity in food availability creates variation in infectious disease susceptibility.
Department of Virology, University of Helsinki, Helsinki, Finland kristian.forbes@helsinki.fi.
Kristian M
http://orcid.org/0000-0002-2112-2707
KM
Forbes
Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland.
Tapio
T
Mappes
Department of Virology, University of Helsinki, Helsinki, Finland.
Tarja
T
Sironen
Department of Virology, University of Helsinki, Helsinki, Finland.
Tomas
T
Strandin
Department of Zoology, Trinity College, Dublin, Ireland.
Peter
P
Stuart
Department of Bacteriology and Immunology, University of Helsinki, Helsinki, Finland Immunobiology Reseach Programme, University of Helsinki, Helsinki, Finland.
Seppo
S
Meri
Department of Virology, University of Helsinki, Helsinki, Finland Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland Helsinki University Hospital, University of Helsinki, Helsinki, Finland.
Olli
O
Vapalahti
Forest and Animal Ecology, Natural Resources Institute Finland, Vantaa, Finland.
Heikki
H
Henttonen
Forest and Animal Ecology, Natural Resources Institute Finland, Vantaa, Finland.
Otso
O
Huitu
eco-immunology; field experiment; ivermectin; parasite; vole
Am Nat. 2002 Oct;160 Suppl 4:S9-S22
18707455
Mol Ecol. 2011 Mar;20(5):872-80
21324009
Oecologia. 1985 Oct;67(3):394-402
28311574
Trends Parasitol. 2015 May;31(5):200-11
25778845
Int J Parasitol. 1995 Nov;25(11):1331-51
8635884
Biol Lett. 2011 Feb 23;7(1):101-4
20659921
Trends Ecol Evol. 2010 Jan;25(1):21-7
19782425
J Anim Ecol. 2008 Sep;77(5):984-97
18564292
Trends Ecol Evol. 1996 Aug;11(8):317-21
21237861
Biol Lett. 2016 Sep;12(9):
27677814
Nat Rev Immunol. 2007 Dec;7(12):975-87
18007680
Proc Biol Sci. 2015 Oct 7;282(1816):20151939
26446813
Ecology. 2008 Aug;89(8):2251-8
18724735
J Anim Ecol. 2008 Mar;77(2):370-7
18028357
Cell Host Microbe. 2008 Oct 16;4(4):362-73
18854240
Comp Immunol Microbiol Infect Dis. 2000 Mar;23(2):73-89
10670697