Physiological and morphological responses to simultaneous cold exposure and parasite infection by wild-derived house mice


*Present address and correspondence. Department of Biological Sciences, PO Box 3051, University of Idaho, Moscow, ID 83844–3051, USA. Tel. +1 208 885-6905. Fax +1 208 8857905. E-mail


  • 1Many animals respond to environmental demands with phenotypic plasticity of morphology and physiology. We examined the effects of ambient temperature and parasitism on morphology and physiology of wild-derived house mice (Mus musculus) that were exposed to cold and/or experimentally infected with a naturally occurring intestinal nematode (Heligmosomoides polygyrus).
  • 2Parasitized mice had changes in some organ masses, decreased ability to digest food, and lower rates of glucose transport but similar total glucose transport capacity as unparasitized mice. Wild-derived house mice did not use fat stores to respond to parasitism but did increase mucosal mass in the small intestine enough to maintain glucose acquisition at a similar level to unparasitized mice.
  • 3Cold-exposed mice showed increased masses of some organs, lower rates of glucose transport but similar total capacity to transport glucose as warm acclimated mice.
  • 4The effects of cold exposure and parasite infection were largely independent of each other for the morphological and physiological parameters we measured.
  • 5The more recent exposure of wild-derived house mice to fluctuating temperatures and to parasite infection may help to explain the subtle differences that we observed in how wild-derived mice respond to environmental demands compared to their laboratory mouse counterparts.