Because the gut microbiota contributes to host nutrition, health and behavior, and gut microbial community composition differs according to host phylogeny, co-evolution is believed to have been an important mechanism in the formation of the host-gut microbe relationship. However, current research is not ideal for examining this theme. Most studies of the gut microbiota are performed in controlled settings, but gut microbial community composition is strongly influenced by environmental factors. To truly explore the co-evolution of host and microbe, it is necessary to have data describing host-microbe dynamics in natural environments with variation in factors such as climate, food availability, disease prevalence, and host behavior. In this review, I use current knowledge of host-gut microbe dynamics to explore the potential interactions between host and microbe in natural habitats. These interactions include the influence of host habitat on gut microbial community composition as well as the impacts of the gut microbiota on host fitness in a given habitat. Based on what we currently know, the potential connections between host habitat, the gut microbiota, and host fitness are great. Studies of wild animals will be an essential next step to test these connections and to advance our understanding of host-gut microbe co-evolution.
 Forsythe P., Sudo N., Dinan T., Taylor V.H., Bienenstock J.
Mood and gut feelings. Brain Behav Immun 2010; 24: 9-16
 Flint H.J., Bayer E.A. Plant cell wall breakdown by anaerobic
microorganisms from the mammalian digestive tract. Ann NY
Acad Sci 2008: 280-288
 Flint H.J., Duncan S.H., Louis P., Impact of intestinal microbial
communities upon health., In: Rosenberg E, Gophna U.
(Eds.), Beneficial Microorganisms in Multicellular Life Forms
Springer, Berlin, 2011 243-252.
Financed by the National Centre for Research and Development under grant No. SP/I/1/77065/10 by the strategic scientific research and experimental development program:
SYNAT - “Interdisciplinary System for Interactive Scientific and Scientific-Technical Information”.