A reply to “Ranging Behavior Drives Parasite Richness: A More Parsimonious Hypothesis”

Marie Charpentier,Peter Kappeler

doi:10.3897/rethinkingecology.3.29573

Abstract

This preprint has been reviewed and recommended by Peer Community In Ecology (https://dx.doi.org/10.24072/pci.ecology.100001). In a recent article, Bicca-Marques and Calegaro-Marques [Bicca-Marques JC, Calegaro-Marques C (2016) Ranging behavior drives parasite richness: A more parsimonious hypothesis. American Journal of Primatology 78: 923–927.] discussed the putative assumptions related to an interpretation we provided regarding an observed positive relationship between weekly averaged parasite richness of a group of mandrills (Mandrillussphinx) and their daily path lengths (DPL), published earlier in the same journal [Brockmeyer T, Kappeler PM, Willaume E, Benoit L, Mboumba S, Charpentier MJE (2015) Social organization and space use of a wild mandrill (Mandrillussphinx) group. American Journal of Primatology 77: 1036–1048.]. In our article, we proposed, inter alia, that “the daily travels of mandrills could be seen as a way to escape contaminated habitats on a local scale”. In their article, Bicca-Marques and Calegaro-Marques proposed an alternative mechanism that they considered to be more parsimonious. In their view, increased DPL also increases exposure to novel parasites from the environment. In other words, while we proposed that elevated DPL may be a consequence of elevated parasite richness, they viewed it as a cause. We are happy to see that our study attracted so much interest that it evoked a public comment. We are also grateful to Bicca-Marques and Calegaro-Marques for pointing out an obvious alternative scenario that we failed to discuss and for laying out several key factors and assumptions that should be addressed by future studies examining the links between parasite risk and group ranging. We use this opportunity to advance this discourse by responding to some of the criticisms raised in their discussion of our article. In this reply, we briefly contextualize the main object of criticism. We then discuss the putative parsimony of the two competing scenarios.

Highlights

Little is still known about how wild animals organize their ranging behavior in response to the risks emanating from environmentally-transmitted parasites
Bicca-Marques and Calegaro-Marques (2016) proposed that our interpretation of the observed positive relationship between daily path length (DPL) and parasite richness at the group level was based upon four implicit assumptions
Assumption 2 states that symptoms are more severe in multi-infected individuals or that the probability of hosting a pathogenic species is higher in these animals

Summary

Introduction

Bicca-Marques and Calegaro-Marques (2016) subsequently questioned this interpretation of one of several correlative relationships reported in the second part of our article. By not acknowledging the main focus of our paper and the preliminary nature of the analysis of the group’s ranging behavior, which was yet clearly stated, Bicca-Marques and Calegaro-Marques (2016) have created, in our view, a heavily distorted point of departure for their article.

Results

Conclusion