Behavioral Ecology and Sociobiology

, Volume 59, Issue 1, pp 30–37

Malaria infection and host behavior: a comparative study of Neotropical primates

Original Article

DOI: 10.1007/s00265-005-0005-z

Cite this article as:
Nunn, C.L. & Heymann, E.W. Behav Ecol Sociobiol (2005) 59: 30. doi:10.1007/s00265-005-0005-z


Parasites are ubiquitous in populations of free-ranging animals and impact host fitness, but virtually nothing is known about the factors that influence patterns of disease risk across species and the effectiveness of behavioral defenses to reduce this risk. We investigated the correlates of malaria infection (prevalence) in Neotropical primates using data from the literature, focusing on host traits involving group size, body mass, and sleeping behavior. Malaria is spread to these monkeys through anopheline mosquitoes that search for hosts at night using olfactory cues. In comparative tests that used two different phylogenetic trees, we confirmed that malaria prevalence increases with group size in Neotropical primates, as suggested by a previous non-phylogenetic analysis. These results are consistent with the hypothesis that larger groups experience increased risk of attack by mosquitoes, and counter to the hypothesis that primates benefit from the encounter-dilution effect of avoiding actively-seeking insects by living in larger groups. In contrast to non-phylogenetic tests, body mass was significant in fewer phylogeny-based analyses, and primarily when group size was included as a covariate. We also found statistical support for the hypothesis that sleeping in closed microhabitats, such as tree holes or tangles of vegetation, reduces the risk of malaria infection by containing the host cues used by mosquitoes to locate hosts. Due to the small number of evolutionary transitions in sleeping behavior in this group of primates, however, this result is considered preliminary until repeated with a larger sample size. In summary, risk of infection with malaria and other vector-borne diseases are likely to act as a cost of living in groups, rather than a benefit, and sleeping site selection may provide benefits by reducing rates of attack by malaria vectors.


Malaria Primates Prevalence Group size Sleeping behavior Comparative study 

Supplementary material

265_2005_5_Fig1_ESM.gif (31 kb)
Tree 1

Phylogenetic tree of New World primates based on Purvis (1995), with taxonomic adjustment noted in the text. Numbers indicate branch length in Ma. This tree is referred to as Purvis in the Table 2.

265_2005_5_Fig2_ESM.gif (31 kb)
Tree 2

Phylogenetic tree of New World primates based on Porter et al. (1997), Schneider (2000) and Goodman et al. (1998). This tree is referred to as PSG in Table 2. Numbers indicate branch length in Ma. In addition to branch length differences, which were based on information in the references, the major differences to the Purvis tree involve the position of Aotus, the internal arrangement of the marmosets (Callithrix, Cebuella, Mico), and arrangement of species in the clade containing Ateles.

Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  1. 1.University of CaliforniaDepartment of Integrative BiologyBerkeleyUSA
  2. 2.Abteilung Verhaltensökologie & SoziobiologieDeutsches PrimatenzentrumGöttingenGermany

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