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

TL;DR

This paper responds to critiques of a previous study on mandrill parasite richness and ranging behavior, debating whether increased movement causes or results from parasite exposure, and emphasizes the need for further research.

Contribution

The authors clarify their original hypothesis and address alternative explanations, advancing the discussion on causality between ranging behavior and parasite richness in primates.

Findings

The original study observed a positive correlation between parasite richness and daily path length.

The authors defend their hypothesis that increased movement may be a response to parasite risk.

They highlight the importance of future studies to disentangle causality in parasite-host interactions.

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 [2016] 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 (Mandrillus sphinx) and their daily path lengths (DPL), published earlier in the same journal (Brockmeyer et al., 2015). 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 [2016] 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 [2016] 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.