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Data from: The enemy within: how does a bacterium inhibit the foraging aptitude and risk management behavior of Allenby’s gerbils?

Citation

Makin, Douglas Ferguson et al. (2020), Data from: The enemy within: how does a bacterium inhibit the foraging aptitude and risk management behavior of Allenby’s gerbils?, Dryad, Dataset, https://doi.org/10.5061/dryad.wpzgmsbjd

Abstract

Microbes inhabiting multi-cellular organisms have complex, often subtle effects on their hosts. Gerbillus andersoni allenbyi are commonly infected with the Mycoplasma haemomuris-like bacteria, which may cause mild nutrient (choline, arginine) deficiencies. However, are there more serious ecological consequences of infection such as effects on foraging aptitudes and risk management? We tested alternatives: 1) nutrient compensation hypothesis, does nutrient deficiency induce infected gerbils to make up for the shortfall by foraging more and taking greater risks? or 2) lethargy hypothesis, do sick gerbils forage less, and are they compromised in their ability to detect predators or risky microhabitats? We compared the foraging and risk management behavior of infected and non-infected gerbils. We experimentally infected gerbils with the bacteria, which allowed us to compare between non-infected, acutely infected (peak infection loads), and chronically infected (low infection loads) individuals. Our findings supported the lethargy hypothesis over the nutrient compensation hypothesis. Infected individuals incurred dramatically elevated foraging costs, including less efficient foraging, diminished “quality” of time spent vigilant, and increased owl predation. Interestingly, gerbils that were chronically infected (lower bacteria load) experienced larger ecological costs than acutely infected individuals (i.e. peak infection loads). This suggests that the debilitating effects of infection occur gradually, with a progressive decline in the quality of time gerbils allocated to foraging and managing risk. These increased long-term costs of infection demonstrate how small direct physiological costs of infection can lead to large indirect ecological costs. The indirect ecological costs of this parasite appear much greater than the direct physiological costs.