DOI: 10.5061/dryad.kwh70rzdv
title: Data from: Antipredator behavioural syndromes and nest site choice in a freshwater turtle

description: Behavioural syndromes, correlated suites of behaviour across time or
 contexts, lend insight into ecological and evolutionary causes and
 consequences of animal behaviour. While descriptive studies documenting
 the presence of behavioural syndromes across taxa have become more common,
 fewer studies seek to determine how behavioural syndrome expression may
 drive broader ecological and evolutionary processes, especially in wild
 populations. In this study, we leverage the complex nesting ecology of a
 free-ranging population of painted turtles, Chrysemys picta, to
 determine whether and how behavioural syndromes alter nest site choice in
 the field. We quantify an antipredator behavioural syndrome in this
 species and demonstrate, for the first time, that one measure of
 behavioural boldness predicts nesting behaviour. We document the presence
 of behavioural syndromes by demonstrating a correlation between behaviours
 displayed in a simulated predation trial and a novel environment assay in
 the field. Turtles that displayed more active defences under simulated
 predation were faster to explore a novel environment, signalling a
 consistent behaviour type across contexts. Emergence latency, one measure
 of boldness and exploratory behaviour, predicted the extent of canopy
 cover at nest sites; specifically, bolder turtles chose nest sites with
 less canopy cover, which has well-documented consequences for nest thermal
 environments and, subsequently, offspring phenotypes. Together, these
 results provide further evidence for the presence of behavioural syndromes
 in this taxon and demonstrate that behaviour type should be considered
 when elucidating the factors that influence nest site choice and its
 associated ecological and evolutionary consequences.
description: Field Methods: For this study, we used a population of painted
 turtles at the Thomson Causeway Recreational Area (TCRA) in Thomson,
 Illinois, U.S.A. This site is composed of grass and campsites created with
 concrete pads and gravel situated between a slough on the Mississippi
 River and a deciduous forest. The TCRA has been used as a research site
 for several decades to study painted turtle nesting patterns and behaviour
 (Delaney et al., 2020; Reinke et al., 2019). Recreational visitors were
 absent on the island during this study due to a campsite
 closure. We conducted hourly surveys for nesting
 painted turtles from 29 May to 2 June 2023. In total, we surveyed 30
 individuals. When we observed a turtle beginning to nest, we recorded its
 approximate location and continued observations from ~10 m away using
 binoculars such that turtles would not perceive human observers.
 Immediately after nest completion, one team member started the simulated
 predation assay while another member recorded nest characteristics. We
 measured the distance (m) between the nest and the nearest anthropogenic
 structure using a measuring tape placed at the centre of the nest. Objects
 deemed anthropogenic structures included concrete pads, gravel paths,
 electrical boxes, railroad ties, and construction materials. We measured
 distance from the shoreline (m) using a laser rangefinder or, in cases
 where the nest was very close to the shoreline, a measuring tape. We took
 hemispherical photographs directly above the nest and quantified
 percentage total canopy
 openness and percentage of southwest canopy openness using Gaplight
 Analyzer Software (Cary Institute of Ecosystem Studies, Millbrook, NY,
 U.S.A.) (Mitchell et al., 2015). At this study site, C. picta nest
 temperature and, consequently, offspring sex ratio are driven by southwest
 canopy cover in particular (Janzen, 1994a; Schwanz et al.,
 2010). Raccoons are the most prevalent turtle predator
 at this field site, so we created a taxidermized raccoon outfitted with
 original claws and acrylic teeth to simulate realistic tactile and visual
 predation cues (Fig. 1). Painted turtles have reduced olfactory perception
 capabilities on land as they spend most of their time in water (Vieyra,
 2011). Thus, for the purposes of this study, we did not scent the model
 predator for the assays, and instead focused on creating visual and
 tactile cues that painted turtles are more likely to perceive on land
 (Pich et al., 2019). After the turtle had completed
 nesting and had begun to return to the water, we approached it from behind
 with the simulated predator. The same team member (M.A.C.) conducted each
 simulated predation assay. Time began for the 180 s assay period when the
 raccoon contacted the turtle’s carapace. Simulated predation began as
 gentle probing with the teeth and claws on and around the carapace until
 90 s had passed, at which time the turtle was gently overturned (see
 methods: Pich et al., 2019). Probing with teeth and claws continued while
 the turtle’s plastron was exposed for 90 s. The raccoon was manipulated to
 probe the turtle constantly and continuously throughout the duration of
 the assay, with consistent effort between individuals. While we
 manipulated the turtle with the raccoon ‘predator,’ we took care to keep
 the turtle’s head facing away from team members to reduce visual
 perception of researchers. During the assay, a team member not
 manipulating the raccoon recorded counts of antipredator behaviour.
 Antipredator behaviours were grouped into either active (hissing, biting,
 urinating/defecating, opening mouth, head pushing) or passive (withdrawing
 and fleeing) categories (as per Roth et al., 2020). We considered active
 defences as an index of boldness (Zhao et al., 2016), with bolder turtles
 displaying a higher count of active defences than shyer turtles.
 After the simulated predation assay, we placed the turtle inside
 an opaque 5-gallon (18.9-litre) plastic bucket
 and set the bucket away from human disturbance. The turtle remained in the
 bucket for 15 min to rest between behavioural assays and to minimize or
 eliminate any influence of the first behaviour assay on the second (see
 Roth et al., 2020). Limited evidence quantifying the acute stress response
 of painted turtles at this field site suggests that circulating levels of
 corticosterone begin to decrease 10 min after
 handling (Polich, 2018).* *After the 15 min habituation period was
 complete, we transferred the turtle to a plastic novel arena with a 91 cm
 diameter. The arena had a ~15 cm high wall to ensure the turtle could not
 immediately perceive external lateral visual cues. At the beginning of the
 assay, we placed the turtle in the middle of the arena with the head
 facing away from the observer, and then started a stopwatch. The observer
 stood 3 m away and recorded the latency for any part of the turtle’s head
 to emerge from the shell and be visible (emergence latency) and the
 latency for the turtle to move its body so that the original position of
 the carapace was displaced (movement latency) (Roth et al., 2020). The
 assay stopped when the turtle moved its body or the timer reached 180 s,
 whichever occurred first. We considered emergence latency and movement
 latency as indices for boldness, with bolder turtles having lower
 emergence and movement latency scores than shyer turtles (Zhao et al.,
 2016).
description: # Data from: Antipredator behavioural syndromes and nest site choice in a
 freshwater turtle Dataset DOI:
 [10.5061/dryad.kwh70rzdv](10.5061/dryad.kwh70rzdv) ## Description of the
 data and file structure ### Files and variables ### File:
 Clarketal_2025_Data_AnimalBehaviour.csv **Description:** This dataset
 contains all data used in the study- including behavior data, nest
 characteristics, body characteristics, and temperature data. **Empty
 Cells:** Empty cells are NA values- data that were not collected due to
 logistical constraints in the field. ##### Variables * Mom Number:
 Temporary ID number assigned to each individual * ID: Real ID used in
 mark-recapture efforts at this fieldsite * perc_sw_open: Percent canopy
 southwest openness, calculated with GapLight Analyzer Software *
 perc_can_open : Percent canopy openness total, calculated with GapLight
 Analyzer Software * daily_temp_c: Daily temperature taken from a nearby
 weather monitoring station  * active_defense: Count of total active
 defences displayed during the simulated predation behavioral assay * Hiss:
 Count of total hisses measured within active defences during the simulated
 predation behavioral assay * passive_defense: Count of total passive
 defenses measured during the simulated predation behavioral assay * HEL:
 Emergence Latency (s) during the novel arena exploratory assay * LBM:
 Movement Latency (s) during the novel arena exploratory assay * SCL:
 Straight carapace length (mm) * SCW: Straight carapace width (mm) * SPL:
 Straight plastron length (mm) * SPW : Straight plastron width (mm) * CCL:
 Curved carapace length (mm) * CCW : Curved carapace width (mm) *
 dist_shore: Nest distance to shore (m) * dist_urb: Nest distance to
 nearest anthropogenic structure (m) #### File:
 Clarketal_2025_Data2_AnimalBehaviour.csv **Description:** A reformatted
 dataset used to calculate the spearman's rank correlation between
 behaviors across assays.  ##### Variables * Mom Number: Temporary ID
 number assigned to each individual * active_defense: Count of total active
 defences displayed during the simulated predation behavioral assay, in
 this case, only hisses were counted as active defences. * passive_defense:
 Count of total passive defenses measured during the simulated predation
 behavioral assay * HEL: Emergence Latency (s) during the novel arena
 exploratory assay * LBM: Movement Latency (s) during the novel arena
 exploratory assay ## Code/software We performed all statistical analyses
 using *R* version 4.3.1 (R Core Team, 2023). R packages used:  -DHARMa
 -ggplot2 -pscl -AER -glmmTMB -Hmisc