Smelling fit: scent marking exposes parasitic infection status in the banded mongoose
Oxford University Press (OUP)
© The Author (2017). Published by Oxford University Press. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact email@example.com
Preference for uninfected mates is presumed beneficial as it minimizes one’s risk of contracting an infection and infecting one’s offspring. In avian systems, visual ornaments are often used to indicate parasite burdens and facilitate mate-choice. However, in mammals, olfactory cues have been proposed to act as a mechanism allowing potential mates to be discriminated by infection status. The effect of infection upon mammalian mate-choice is mainly studied in captive rodents where experimental trials support preference for the odors of uninfected mates and some data suggest scent marking is reduced in individuals with high infection burdens. Nevertheless, whether such effects occur in non-model and wild systems remains poorly understood. Here we investigate the interplay between parasite load (estimated using fecal egg counts) and scent marking behavior in a wild population of banded mongooses, Mungus mungo. Focusing on a costly protozoan parasite of the genus Isospora and the nematode worm Toxocara, we first show that banded mongooses that engage in frequent, intensive scent-marking have lower Isospora loads, suggesting marking behavior may be an indicator trait regarding infection status. We then use odor presentations to demonstrate that banded mongooses mark less in response to odors of opposite-sexed individuals with high Isospora and Toxocara loads. As both of these parasites are known to have detrimental effects upon the health of pre-weaned young in other species, they would appear key targets to avoid during mate-choice. Results provide support for scent as an important ornament and mechanism for advertising parasitic infection within wild mammals.
This work was supported by a Liverpool John Moores University scholarship for post-graduate research awarded to JM, and the European Research Council (ERC), grant number 309249 awarded to MAC.
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Published online 14 February 2017