Fitness, risk taking, and spatial behavior covary with boldness in experimental vole populations
Data files
Aug 08, 2023 version files 244.96 KB
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Data_EccardetAl2022_(2).xlsx
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Eccard_et_al._2022_Data_Animals.xlsx
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README.md
Abstract
Individuals of a population may vary along a pace-of-life syndrome from highly fecund, short-lived, bold, dispersive ‘fast’ types at one end of the spectrum to less fecund, long-lived, shy, plastic ‘slow’ types at the other end. Risk-taking behaviour might mediate the underlying life-history trade-off but empirical evidence supporting this hypothesis is still ambiguous. Using experimentally created populations of common voles (Microtus arvalis) - a species with distinct seasonal life-history trajectories - we aimed to test whether individual differences in boldness behaviour co-vary with risk-taking, space use, and fitness. We quantified risk taking, space use (via automated tracking), survival and reproductive success (via genetic parentage analysis) in 8 to 14 experimental, mixed-sex populations of 113 common voles of known boldness type in large grassland enclosures over a significant part of their adult life span and two reproductive events. Populations were assorted to contain extreme boldness types (bold or shy) of both sexes. Bolder individuals took more risks than shyer ones, which did not affect survival. Bolder males but not females produced more offspring than shy conspecifics. Daily home range and core area sizes, based on 95% and 50% Kernel density estimates (20 ± 10 per individual, n = 54 individuals), were highly repeatable over time. Individual space use unfolded differently for sex-boldness type combinations over the course of the experiment. While day ranges decreased for shy females, they increased for bold females and all males. Space use trajectories may, hence, indicate differences in coping styles when confronted with a novel social and physical environment. Thus, inter-individual differences in boldness predict risk taking under near natural conditions and have consequences for fitness in males, which have a higher reproductive potential than females. Given extreme inter- and intra-annual fluctuations in population density in the study species and its short life span, density-dependent fluctuating selection operating differently on the sexes might maintain (co)variation in boldness, risk taking and pace-of-life.
Methods
Our study had three steps (Table 1): we (a) captured individuals from free ranging populations, and selected the extreme boldness types to compose experimental populations, (b) released experimental populations of both sexes into near-natural large outdoor enclosures and recorded space use and risk taking with indirect telemetry methods (ART and RFID) over two reproductive events (5-6 weeks), (c) recaptured individuals from outdoor enclosures to monitor survival and estimate reproductive success based on parentage analysis.
All individuals were wild captured. Boldness tests were assessed repeatedly in standard test for animal personality in the laboratory before individuals were sorted into experimental populations and brought outside into the enclosures.
Usage notes
The data set is structured in two separate files. The file "DataAnimals" contains more detailed information on the personality tests of individuals, like single measured variables, while in the "Data" file data is shown that is the basis of the statistical analysis presented in the manuscript. Cells with NA represent missing values for the respected variable for an individual. This mostly refers to the data on visits to the riskier area of the enclosure which could only be obtained for a subset of individuals.