Colobus Monkey Parasite Infections in Wet and Dry Habitats: Implications for Climate Change

The effect of climate change on animal behavior is an often-studied phenomenon, however the effect of climate change on animal relationships is a less frequently examined sub-topic. In this experiment, Chapman et al. (2010) studied the host parasite relationship and the likely changes it will encounter, should climate change grow more severe. Using the colobus monkeys of Kibale National Park in Uganda as a model, the researchers created a comparison between the monkeys frequenting wet habitats, and those that preferred drier ones. The researchers took fecal samples from the monkeys and analyzed them for gastrointestinal parasites. Two forest sites were chosen for this experiment, Kanyawara and Mainaro. The monkeys were studied in three groups, those who frequented the wet lowlands and dry highlands of Kanyawara, and those who frequented the highlands of Mainaro only. The researchers found that in all cases, the moneys in the wetter areas did show increased instance of intestinal parasites. The effects of parasites such as these on the colobus population have yet to be determined, however some theories suggest that they could be extreme. As climate change is expected to make some drier areas wetter, these findings have implications for the future of colobus monkeys and many other animal populations as well.¾Emily Grace Cole
Chapman, C., Speirs, M., Hodder, S., Rothman, J., 2010. Colobus parasite infections in wet and dry habitats: Implications for climate change.  African Journal of Ecology (In Press).

The researchers chose two study sites for their difference in rainfall per year, but also for their similarities in forestation. While Kanyawara is 30 km north of Mainaro and receives 361 more mm of rain, both sites have comparable biodiversity of the tree community with similarly sized trees, although the species content of the two forests does differ. Primate densities at each site were generally alike, with the exception that Cercopithicus mitis was not present in Mainaro.
Fecal samples were collected from groups of moneys that frequented the highlands and the lowlands of Kanyawara, and also those who frequented the highlands of Mainaro. As colobus monkeys have a small home range, it is unlikely that one group visited both areas. Samples were only collected in May and June of 2005 and 2006 to avoid a seasonal skew of the results. Prior to processing, the samples were stored in a solution of 10% formalin. They were then processed using sodium nitrate and evaluated visually for intestinal parasites.
          The researchers found that the monkeys living in wetter areas showed higher amounts of gastrointestinal parasites. The prevalence of specific parasitic species such as Trichuris sp. was found to be higher, the wetter the area. In addition, the species richness of the parasite community was found to be higher in the lowlands of Kanyawara than in the drier highlands, while both of these areas exhibited higher species richness than the drier Mainaro site.
          While it is not proven that gastrointestinal parasites have severe effects on the populations of their hosts, some studies have suggested they do, especially when their hosts are pressed for food. Chapman et al. also offer up the postulate that since climate change has been shown to alter growth patterns in plants, sometimes inducing food scarcity, it could exacerbate parasitic effects. In any case, the effects of climate change on the host parasite relationship is certainly relevant to the future of many animal populations.

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