Fine‐tuned responses to chemical landscapes: crayfish use predator odors to assess threats based on relative size ratios

Abstract The threat‐sensitive predator avoidance hypothesis suggests that prey animals should minimize the costs of antipredator behaviors by only responding to predators that pose a potentially lethal threat. Thus, prey must use risk assessment strategies to determine which predators present a grea...

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Main Authors: Tyler C. Wood, Paul A. Moore
Format: Article
Language:English
Published: Wiley 2020-09-01
Series:Ecosphere
Subjects:
Online Access:https://doi.org/10.1002/ecs2.3188
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author Tyler C. Wood
Paul A. Moore
author_facet Tyler C. Wood
Paul A. Moore
author_sort Tyler C. Wood
collection DOAJ
description Abstract The threat‐sensitive predator avoidance hypothesis suggests that prey animals should minimize the costs of antipredator behaviors by only responding to predators that pose a potentially lethal threat. Thus, prey must use risk assessment strategies to determine which predators present a great enough threat to merit a response. A rich literature demonstrates that chemical signals can communicate information about predator identity, diet, and size. However, the relationship between predator size and prey size has been largely overlooked. What remains unknown is how prey respond to odors from predators along a continuum of relative size. Here, we tested the responses of crayfish (prey) to odor cues from two species of predatory fish along a gradient of relative size relationships. Crayfish and fish were paired according to crayfish carapace width and the fish’s gape width to represent different relative size pairings. Foraging and shelter use video assays were used to evaluate changes in crayfish behavior under the different levels of threat presented. The analysis revealed significant increases in macrophyte consumption, foraging effort, and overall activity among crayfish that were small relative to their predators, independent of the absolute size of fish or crayfish size. Crayfish that were small relative to predator size showed significantly less shelter use than crayfish that were large relative to predator gape size. The results demonstrate that the crayfish are assessing threat based on their size relative to the predator gape size solely using chemical signals. As a result of this assessment, crayfish are changing their resource use to potentially grow larger to limit future predatory threats. Overall, this research supports the threat‐sensitive predator avoidance hypothesis and provides an opportunity to refine the landscape of fear concept to accommodate more detailed risk assessments by prey.
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spelling doaj.art-465d1f9c183f4999aae727c1470545412022-12-21T21:48:47ZengWileyEcosphere2150-89252020-09-01119n/an/a10.1002/ecs2.3188Fine‐tuned responses to chemical landscapes: crayfish use predator odors to assess threats based on relative size ratiosTyler C. Wood0Paul A. Moore1Laboratory for Sensory Ecology Department of Biological Sciences Bowling Green State University Bowling Green Ohio43402USALaboratory for Sensory Ecology Department of Biological Sciences Bowling Green State University Bowling Green Ohio43402USAAbstract The threat‐sensitive predator avoidance hypothesis suggests that prey animals should minimize the costs of antipredator behaviors by only responding to predators that pose a potentially lethal threat. Thus, prey must use risk assessment strategies to determine which predators present a great enough threat to merit a response. A rich literature demonstrates that chemical signals can communicate information about predator identity, diet, and size. However, the relationship between predator size and prey size has been largely overlooked. What remains unknown is how prey respond to odors from predators along a continuum of relative size. Here, we tested the responses of crayfish (prey) to odor cues from two species of predatory fish along a gradient of relative size relationships. Crayfish and fish were paired according to crayfish carapace width and the fish’s gape width to represent different relative size pairings. Foraging and shelter use video assays were used to evaluate changes in crayfish behavior under the different levels of threat presented. The analysis revealed significant increases in macrophyte consumption, foraging effort, and overall activity among crayfish that were small relative to their predators, independent of the absolute size of fish or crayfish size. Crayfish that were small relative to predator size showed significantly less shelter use than crayfish that were large relative to predator gape size. The results demonstrate that the crayfish are assessing threat based on their size relative to the predator gape size solely using chemical signals. As a result of this assessment, crayfish are changing their resource use to potentially grow larger to limit future predatory threats. Overall, this research supports the threat‐sensitive predator avoidance hypothesis and provides an opportunity to refine the landscape of fear concept to accommodate more detailed risk assessments by prey.https://doi.org/10.1002/ecs2.3188crayfishgape ratioLargemouth Basspredator odorRainbow Troutthreat sensitive
spellingShingle Tyler C. Wood
Paul A. Moore
Fine‐tuned responses to chemical landscapes: crayfish use predator odors to assess threats based on relative size ratios
Ecosphere
crayfish
gape ratio
Largemouth Bass
predator odor
Rainbow Trout
threat sensitive
title Fine‐tuned responses to chemical landscapes: crayfish use predator odors to assess threats based on relative size ratios
title_full Fine‐tuned responses to chemical landscapes: crayfish use predator odors to assess threats based on relative size ratios
title_fullStr Fine‐tuned responses to chemical landscapes: crayfish use predator odors to assess threats based on relative size ratios
title_full_unstemmed Fine‐tuned responses to chemical landscapes: crayfish use predator odors to assess threats based on relative size ratios
title_short Fine‐tuned responses to chemical landscapes: crayfish use predator odors to assess threats based on relative size ratios
title_sort fine tuned responses to chemical landscapes crayfish use predator odors to assess threats based on relative size ratios
topic crayfish
gape ratio
Largemouth Bass
predator odor
Rainbow Trout
threat sensitive
url https://doi.org/10.1002/ecs2.3188
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AT paulamoore finetunedresponsestochemicallandscapescrayfishusepredatorodorstoassessthreatsbasedonrelativesizeratios