DOI: 10.5061/dryad.w9ghx3fzt
title: Interaction between anthropogenic stressors affects antipredator defence in an intertidal crustacean

description: The marine environment is increasingly subject to changes driven by
 anthropogenic stressors which may alter species’ key behaviours and impact
 phenotypic plasticity. Such stressors rarely occur in isolation, yet our
 understanding of how simultaneous stresses affect marine organisms is
 limited. Here we study the combined impacts of a major global stressor,
 temperature increase, and a local stressor, anthropogenic noise, upon key
 defensive traits of the shore crab, Carcinus maenas. We tested the colour
 change and behavioural responses of crabs in relatively colder and warmer
 water, and in the presence of natural ambient or ship noise. Using image
 analysis and a model of predator vision, we demonstrate that crabs change
 colour, and improve camouflage, fastest in warmer water in the absence of
 anthropogenic noise. When anthropogenic noise was present it adversely
 impacted crab colour change and camouflage, to the extent that the
 accelerated change due to temperature was negated. Additionally,
 anthropogenic noise affected C. maenas’ behaviour, reducing the likelihood
 and increasing the latency of antipredator response to stimuli. This
 reveals a possible mitigative antagonism, with the biological response to
 temperature reduced by the presence of anthropogenic noise. Our study
 demonstrates how interactions between anthropogenic stressors may impact
 marine life.
description: Juvenile Carcinus maenas were exposed to a combination of
 anthropogenic noise and raised temperatures in a laboratory environment.
 Impacts of this stressor combination on crab luminance change and
 background matching ability were measured through image analysis with
 respect to an avian predator vision model. Crabs were also montored in
 behavioural trials for their likelihood and time taken to react to a
 simulated predatory attack under stressor combinations.
description: # Interaction between anthropogenic stressors affects antipredator defence
 in an intertidal crustacean
 [https://doi.org/10.5061/dryad.w9ghx3fzt](https://doi.org/10.5061/dryad.w9ghx3fzt) ## Description of the data and file structure Juvenile *Carcinus maenas* were exposed to a combination of anthropogenic noise and raised temperatures in a laboratory environment. Impacts of this stressor combination on crab luminance change and background matching ability were measured through image analysis with respect to an avian predator vision model. Crabs were also monitored in behavioural trials for their likelihood and time taken to react to a simulated predatory attack under stressor combinations. ### Files and variables #### File: carcinus.maenas.luminance.csv **Description:**  ##### Variables * crab.id: each crabs individual identifier during the study * temperature: temperature experienced by crabs; a "hot" temperature treatment of 24 degrees Celsius and a "cold, a temperature treatment of 14 degrees Celsius. * noise:  "ship" noise refers to simulated anthropogenic noise pollution treatment. and "ambient" to a control treatment of ambient sounds played at the same temperature. * weight.g: weight of each crab in grams. * width.mm: width of each crab in millimetres, measured at the widest point of the carapace (spine to spine) * luminance: crab carapace luminance generated through image analysis with respect to an avian predatory visual model * moult.no: Number of moults experienced by each crab * moult: Moult Yes/No * week: Week 0 or 6; start and end of experimental period * background.match: difference between luminance reading of the crab carapace and of the background. #### File: carcinus.maenas.antipredator.csv **Description:**  ##### Variables * temperature.treatment: temperature experienced by crabs; a "hot" temperature treatment of 24 degrees Celsius and a "cold, a temperature treatment of 14 degrees Celsius. * sound.played: "ship" noise refers to simulated anthropogenic noise pollution treatment. and "ambient" to a control treatment of ambient sounds played at the same temperature. * retreat: Whether crabs retreated from a simulated predatory attack (Yes "Y"/No "N") * time: Time taken for crab to retreat to shelter following attack in seconds. * previous.exposure: Exposure of crabs to noise treatments in the luminance change experiment, which was conducted prior to the behavioural trials.