DOI: 10.5061/dryad.tqjq2bwbb
title: Data from: Risk allocation in a freshwater gastropod

description: To balance the basic needs of organisms, internal and external cues are
 used to inform the optimal behavioral strategy. Some of the best-studied
 related cognitive rules have emerged in predator-prey contexts, such as
 the threat-sensitivity hypothesis, which postulates that prey should
 adjust their antipredator behavior in accordance with the level of risk.
 Extending this theory, the risk allocation hypothesis posits that under
 long-term sustained high predation risk, individuals should decrease their
 antipredator responses towards risky stimuli so as to meet their energetic
 demands. Evidence for the risk allocation hypothesis has been mixed in
 invertebrates, particularly in gastropods that are classic model systems
 for antipredator responses. This may be due to past studies frequently
 lacking sham controls and/or sufficient certainty about the risk regime.
 The present study in the aquatic gastropod Physella acuta controls for
 these factors by crossing long-term background risk, i.e., lifelong
 consistent exposure to conspecific alarm cues (high-risk), a reliable cue
 of high predation risk, or a water control (low-risk), with exposure to a
 high-risk or low-risk stimulus. Crawl-out behavior is an adaptive
 antipredator response in gastropods. In accordance with
 threat-sensitivity, high-risk stimuli induced increased crawl-out behavior
 independent of background risk. Providing partial support for risk
 allocation, high background risk induced lower responsivity to both
 low-risk and high-risk chemical stimuli. This may be because cue addition
 also provided tactile cues that could be considered risky by high
 background risk snails. Altogether, the present well-controlled research
 contributes novel data to the hitherto mixed evidence for risk allocation
 in gastropods.
description: # Risk allocation in a freshwater gastropod Dataset DOI:
 [10.5061/dryad.tqjq2bwbb](10.5061/dryad.tqjq2bwbb) ## Description of the
 data and file structure This data originates from a laboratory study on
 the freshwater gastropod *Physella acuta*. In a split-clutch design,
 individuals were raised under either low or high background risk
 (high-risk: conspecific alarm cues or low-risk: a water control). At 28
 days age, their crawl-out behavior was observed prior and after the
 addition of either a low-risk or high-risk cue; stimulus risk was fully
 crossed with background risk. Afterwards, we also assessed morphology in a
 subset of experimental snails. Detailed information on how the data was
 obtained is contained in the corresponding manuscript. ### Files and
 variables **Description of data files**
 **2025-05-21-crawl-datasheet-full-wide.csv** – File containing per-tank
 behavioral and morphological data in wide format for analysis.
 **2025-05-21-crawl-datasheet-long-interval.csv** – File containing
 per-tank behavioral and morphological data in long format for analysis.
 **2025-05-21-individual-morphology-dataset.csv** – File containing
 morphological data for individual snails.
 **2025-05-29-ancestral-shapes-derandomized-fixed.TPS** – File containing
 shell landmark data used for geometric morphometric analyses
 **2025-09-04-pre-post-dataset-long.csv** – File containing average
 per-tank behaviors in long format for visualization purposes.
 **curveslide.csv** – File defining semilandmark identity for geometric
 morphometric analyses **shape.links.csv** – File defining which landmarks
 should be connected with lines; necessary for interpretation of shell
 shape measurements **shape-photos.zip** – Compressed archive containing
 all snail photos used for geometric morphometric analyses. For more detail
 see column *shape_photo_id *in the file
 2025-05-21-individual-morphology-dataset.csv **Description of column names
 within data files** * date – The date at which the behavioral experiment
 was performed at. - tank – Identifies the tank containing the tested group
 of snails. * family – Identifies the family (i.e., maternal ID) that the
 sampled individuals were born from. - replicate – Identifies the replicate
 tank that mothers were sampled from. * background.treatment – Identifies
 the background risk treatment that tested snails were exposed to from
 birth onwards (AC = alarm cues, W = water control). - snail_number – The
 number of snails within the tank containing the tested group of snails. *
 snails_dead – The number of snails that died during development within the
 tank containing the tested group of snails. - stimulus.treatment –
 Identifies the stimulus risk treatment that that tested snails were
 exposed to during the behavioral experiment (AC = alarm cues, W = water
 control). * treatment.combination – Identifies the background risk –
 stimulus risk treatment combination that each tested snail group
 experienced. - mean_shell_size_mm2 – Average shell centroid size of snails
 within the tank containing the tested group of snails. NA = not available
 * CV_shell_size_mm2 – Coefficient of variation in shell centroid size of
 snails within the tank containing the tested group of snails. NA = not
 available - pre_5m_num – Number of snails out of the water after 5 minutes
 of the prestimulus period. * pre_10m_num – Number of snails out of the
 water after 10 minutes of the prestimulus period. - pre_15m_num – Number
 of snails out of the water after 15 minutes of the prestimulus period. *
 pre_20m_num – Number of snails out of the water after 20 minutes of the
 prestimulus period. - pre_25m_num – Number of snails out of the water
 after 25 minutes of the prestimulus period. * pre_30m_num – Number of
 snails out of the water after 30 minutes of the prestimulus period. -
 post_5m_num – Number of snails out of the water 5 minutes after they
 received the stimulus (poststimulus period) * post_10m_num – Number of
 snails out of the water 10 minutes after they received their assigned
 stimulus (poststimulus period) - post_15m_num – Number of snails out of
 the water1 5 minutes after they received their assigned stimulus
 (poststimulus period) * post_20m_num – Number of snails out of the water
 20 minutes after they received their assigned stimulus (poststimulus
 period) - post_25m_num – Number of snails out of the water 25 minutes
 after they received their assigned stimulus (poststimulus period) *
 post_30m_num – Number of snails out of the water 30 minutes after they
 received their assigned stimulus (poststimulus period) - pre_5m_prop –
 Proportion of snails out of the water after 5 minutes of the prestimulus
 period. * pre_10m_prop – Proportion of snails out of the water after 10
 minutes of the prestimulus period. - pre_15m_prop – Proportion of snails
 out of the water after 15 minutes of the prestimulus period. *
 pre_20m_prop – Proportion of snails out of the water after 20 minutes of
 the prestimulus period. - pre_25m_prop – Proportion of snails out of the
 water after 25 minutes of the prestimulus period. * pre_30m_prop –
 Proportion of snails out of the water after 30 minutes of the prestimulus
 period. - post_5m_prop – Proportion of snails out of the water 5 minutes
 after they received the stimulus (poststimulus period) * post_10m_prop –
 Proportion of snails out of the water 10 minutes after they received the
 stimulus (poststimulus period) - post_15m_prop – Proportion of snails out
 of the water 15 minutes after they received the stimulus (poststimulus
 period) * post_20m_prop – Proportion of snails out of the water 20 minutes
 after they received the stimulus (poststimulus period) - post_25m_prop –
 Proportion of snails out of the water 25 minutes after they received the
 stimulus (poststimulus period) * post_30m_prop – Proportion of snails out
 of the water 30 minutes after they received the stimulus (poststimulus
 period) - pre_avg_prop – Average proportion of snails out of the water
 within the prestimulus period. * post_avg_prop – Average proportion of
 snails out of the water within the poststimulus period. - diff_avg_prop –
 Change in the average proportion of snails out of the water between
 prestimulus and poststimulus periods (poststimulus-prestimulus; positive
 values thus indicate more crawl-out behavior in the poststimulus period) *
 pre_avg_num – Average number of snails out of the water within the
 prestimulus period. - post_avg_num – Average number of snails out of the
 water within the poststimulus period. * diff_avg_num – Change in the
 average number of snails out of the water between prestimulus and
 poststimulus periods (poststimulus-prestimulus; positive values thus
 indicate more crawl-out behavior in the poststimulus period) -
 mean_avg_thickness – Average shell thickness of snails within the tank
 containing the tested group of snails. NA = not available * mean_shape_PC3
 – Average defensive shell shape (third principal component) of snails
 within the tank containing the tested group of snails. NA = not available
 - outside – Number of snails out of the water. * inside – Number of snails
 inside the water. - prop_outside – Proportion of snails out of the water.
 * interval_total – Time interval across the whole experiment
 (prestimulus+poststimulus) that crawl-out behavior was sampled at. -
 interval_within – Time interval within prestimulus and poststimulus
 periods that crawl-out behavior was sampled at. * phase – Phase that the
 sampled crawl-out behavior belongs to: prestimulus or poststimulus -
 snail_id_overall – Identifies individual sampled snails. * shape_photo_id
 – Identifies the name of the photo used for morphometric measurement of
 individual sampled snails. All photos referenced here are located in the
 compressed archive shape-photos.zip - treatment – Identifies the
 background risk treatment that tested snails were exposed to from birth
 onwards (AC = alarm cues, W = water control). * snail_id_tank – Identifies
 the order that snails from each tank were sampled in. - thickness_1_mm –
 Shell thickness assessed at the top of the aperture with a caliper. *
 thickness_2_mm – Shell thickness assessed at the middle of the aperture
 with a caliper. - thickness_3_mm – Shell thickness assessed at the bottom
 of the aperture with a caliper. * avg_thickness – Average shell thickness
 (top, middle, bottom of the aperture). - csize_mm2 – Shell centroid size,
 assessed via geometric morphometrics from landmarks. * shape_PC1 – The
 first principal component of shell shape, assessed via geometric
 morphometrics from landmarks. - shape_PC2 – The second principal component
 of shell shape, assessed via geometric morphometrics from landmarks. *
 shape_PC3 – The third principal component of shell shape, assessed via
 geometric morphometrics from landmarks. - shape_PC4 – The fourth principal
 component of shell shape, assessed via geometric morphometrics from
 landmarks. * shape_PC5 – The fifth principal component of shell shape,
 assessed via geometric morphometrics from landmarks. - shape_PC6 – The
 sixth principal component of shell shape, assessed via geometric
 morphometrics from landmarks. * combo.treatment – Identifies the
 background risk – stimulus risk treatment combination that each tested
 snail group experienced. - treatment_fig – Identifies the phase –
 background risk – stimulus risk treatment combination that each datapoint
 belongs to. The leading letter orders the results within the x-axis of the
 overall effect figure. * treatment_fig_background – Identifies the phase –
 background risk treatment combination that each datapoint belongs to. The
 leading letter orders the results within the x-axis of the background risk
 effect figure. - treatment_fig_stimulus – Identifies the phase – stimulus
 risk treatment combination that each datapoint belongs to. The leading
 letter orders the results within the x-axis of the stimulus risk effect
 figure. ## Code/software tpsDig2 ‘2.32’ (
 [https://www.sbmorphometrics.org/soft-dataacq.html
 )](https://www.sbmorphometrics.org/soft-dataacq.html) ``` R
 '4.4.2' The following are the R packages and the version ``` ```
 ## showtext showtextdb sysfonts Hmisc ## "0.9-7" "3.0"
 "0.8.9" "5.2-0" ## boot see scales ggforce ##
 "1.3-31" "0.9.0" "1.3.0" "0.4.2"
 ## ggpmisc ggpp knitr svglite ## "0.6.0" "0.5.8-1"
 "1.49" "2.1.3" ## geomorph rgl RRPP InteractionPoweR
 ## "4.0.8" "1.3.12" "2.0.3"
 "0.2.2" ## lubridate forcats stringr dplyr ## "1.9.3"
 "1.0.0" "1.5.1" "1.1.4" ## purrr readr tidyr
 tibble ## "1.0.2" "2.1.5" "1.3.1"
 "3.2.1" ## ggplot2 tidyverse biotools MASS ## "3.5.1"
 "2.0.0" "4.2" "7.3-61" ## MVN effectsize
 nortest pavo ## "5.9" "0.8.9" "1.0-4"
 "2.9.0" ## emmeans coda sjPlot performance ## "1.10.5"
 "0.19-4.1" "2.8.17" "0.12.4" ## lme4 Matrix
 Rcmdr effects ## "1.1-35.5" "1.7-1" "2.9-5"
 "4.2-2" ## RcmdrMisc sandwich car carData ## "2.9-1"
 "3.1-1" "3.1-3" "3.0-5" ```