DOI: 10.5061/dryad.tmpg4f4xp
title: Micro-personality traits and their implications for behavioural and movement ecology research

description: Many animal personality traits have implicit movement‐based definitions,
 and can directly or indirectly influence ecological and evolutionary
 processes. It has therefore been proposed that animal movement studies
 could benefit from acknowledging and studying consistent inter-individual
 differences (personality), and, conversely, animal personality studies
 could adopt a more quantitative representation of movement patterns. Using
 high-resolution tracking data of three-spined stickleback fish
 (Gasterosteus aculeatus), we examined the repeatability of four movement
 parameters commonly used in the analysis of discrete time-series movement
 data (time stationary, step-length, turning angle, burst frequency), and
 four behavioural parameters commonly used in animal personality studies
 (distance travelled, space use, time in free water, time near objects).
 Fish showed repeatable inter-individual differences in both movement and
 behavioural parameters when observed in a simple environment with two,
 three, or five shelters present. Moreover, individuals that spend less
 time stationary, take more direct paths and less commonly burst travel
 (movement parameters), were found to travel farther, explored more of the
 tank, and spent more time in open water (behavioural parameters). Our
 case-study indicates that the two approaches – quantifying movement and
 behavioural parameters – are broadly equivalent, and we suggest that
 movement parameters can be viewed as “micro-personality” traits that give
 rise to broad-scale consistent inter-individual differences in behaviour.
 This finding has implications for both personality and movement ecology
 research areas. For example, the study of movement parameters may provide
 a robust way to analyse individual personalities in species that are
 difficult or impossible to study using standardised behavioural assays.
description: See published paper for
 full details. In brief: Fish were filmed using a
 Panasonic HDC-SD60 HD video camera (Panasonic Corporation of North
 America, Seraucus, NJ, USA). Video recordings were processed using
 IDTracker (Perez-Escudero <i>et al. </i>2014) to generate x, y
 coordinates for fish, frame by frame (25 Hz recording). Movement was
 therefore considered to be formed by a discrete step-turn process. Data
 was then manually checked and a value of 5mm/s was chosen as a threshold
 to determine movement, which represented movement across frames of less
 than a pixel (Duteil <i>et al.</i> 2016). A sub-sampling rate
 of 2.5 Hz was used to prevent false large turns which can occur due to the
 processing of the video recording (Delcourt <i>et</i><i>
 </i><i>al. </i>2013). The movement threshold and
 sub-sampling rates are in essence arbitrary values but were chosen to
 retain as much information about the movement path, whilst minimising any
 causal effects such smoothing can have on characteristics of movement
 trajectories (Bovet & Benhamou, 1988; Codling & Hill,
 2005; Gurarie & Ovaskainen 2011; Benhamou 2014; Bailey et al,
 2020); different combinations of thresholds and
 subsampling did not affect our findings (Supplementary Material Figures
 S2-S10). For each fish and for each trial
 we then calculated the following movement parameters: (i) Time Stationary
 (% of trial), (ii) Step Length (mean across trial, mm), (iii) Turning
 Angle (mean cosine turn angle, Ө), and (iv) Burst Frequency (the relative
 frequency of periods of movement with a speed above 3 s.d’s of the mean
 step-length of the fish when moving (Kane et al, 2004), and the following
 behavioural parameters: (v) Distance Travelled (total distance travelled
 during trial) (vi) Space Use (proportion of tank two-dimensional space
 explored), (vii) Time Near Object (% of time ‘near’ an object during the
 trial), and (viii) Time in Free Water (% time away from tank edges and
 shelters). Near (or away) from objects was considered as within 7cm
 (larger than fish body length which is on average 5.3cm in our study
 population; Fürtbauer <i>et al. </i>2015); other distances
 were considered from 2cm to 15cm, but results were quantitatively
 similar.
description: Movement parameters and behavioural parameters for individual
 fish, across two weeks of testing (week 1, week 2) in three
 environments (1 – 2 shelters; 2 – 3 shelters; 3 – 5 shelters) are
 provided. Details of movement and behavioural paramaters are described in
 the Methods above. Sinuosity is addionally provided, measured as as: S
 =(-2 log (R) / sl)^0.5, where R = mean resultant vector of turning angles,
 and sl = mean step length.