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When death comes: linking predator-prey activity patterns to timing of mortality to understand predation risk

DOI:10.1098/rspb.2023.0661
Authors:
Shotaro Shiratsuru
Shotaro Shiratsuru
Shotaro Shiratsuru
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E.K. Studd at Thompson Rivers University
E.K. Studd
Stan A Boutin at University of Alberta
Stan A Boutin
Michael J L Peers at Memorial University of Newfoundland
Michael J L Peers
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Abstract

The assumption that activity and foraging are risky for prey underlies many predator-prey theories and has led to the use of predator-prey activity overlap as a proxy of predation risk. However, the simultaneous measures of prey and predator activity along with timing of predation required to test this assumption have not been available. Here, we used accelerometry data on snowshoe hares (Lepus americanus) and Canada lynx (Lynx canadensis) to determine activity patterns of prey and predators and match these to precise timing of predation. Surprisingly we found that lynx kills of hares were as likely to occur during the day when hares were inactive as at night when hares were active. We also found that activity rates of hares were not related to the chance of predation at daily and weekly scales, whereas lynx activity rates positively affected the diel pattern of lynx predation on hares and their weekly kill rates of hares. Our findings suggest that predator-prey diel activity overlap may not always be a good proxy of predation risk, and highlight a need for examining the link between predation and spatio-temporal behaviour of predator and prey to improve our understanding of how predator-prey behavioural interactions drive predation risk.
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Research
Cite this article: Shiratsuru S et al. 2023
When death comes: linking predator–prey
activity patterns to timing of mortality to
understand predation risk. Proc. R. Soc. B 290:
20230661.
https://doi.org/10.1098/rspb.2023.0661
Received: 21 March 2023
Accepted: 21 April 2023
Subject Category:
Ecology
Subject Areas:
behaviour, ecology, ecosystems
Keywords:
predator–prey, diel activity, time of predation,
predation risk, Lepus americanus,Lynx
canadensis
Author for correspondence:
Shotaro Shiratsuru
e-mail: s.shiratsuru@gmail.com
†
These authors contributed equally.
Electronic supplementary material is available
online at https://doi.org/10.6084/m9.figshare.
c.6626115.
When death comes: linking predator–prey
activity patterns to timing of mortality to
understand predation risk
Shotaro Shiratsuru
1,†
, Emily K. Studd
1,2,†
, Stan Boutin
1
, Michael J. L. Peers
1
,
Yasmine N. Majchrzak
1
, Allyson K. Menzies
3
, Rachael Derbyshire
4
,
Thomas S. Jung
5,6
, Charles J. Krebs
7
, Rudy Boonstra
8
and Dennis L. Murray
4
1
Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada T6G 2R3
2
Department of Biological Sciences, Thompson Rivers University, Kamloops, British Columbia, Canada V2C 0B8
3
Department of Natural Resource Sciences, McGill University, St-Anne-de-Bellevue, Québec, Canada H9X 3V9
4
Department of Biology, Trent University, Peterborough, Ontario, Canada
5
Department of Environment, Government of Yukon, Whitehorse, Yukon, Canada
6
Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada
7
Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
8
Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
SS, 0000-0001-8747-9664; MJLP, 0000-0002-3014-2056; RB, 0000-0003-1959-1077
The assumption that activity and foraging are risky for prey underlies many
predator–prey theories and has led to the use of predator–prey activity over-
lap as a proxy of predation risk. However, the simultaneous measures of prey
and predator activity along with timing of predation required to test this
assumption have not been available. Here, we used accelerometry data on
snowshoe hares (Lepus americanus) and Canada lynx (Lynx canadensis)to
determine activity patterns of prey and predators and match these to precise
timing of predation. Surprisingly we found that lynx kills of hares were as
likely to occur during the day when hares were inactive as at night when
hares were active. We also found that activity rates of hares were not related
to the chance of predation at daily and weekly scales, whereas lynx activity
rates positively affected the diel pattern of lynx predation on hares and
their weekly kill rates of hares. Our findings suggest that predator–prey diel
activity overlap may not always be a good proxy of predation risk, and high-
light a need for examining the link between predation and spatio-temporal
behaviour of predator and prey to improve our understanding of how
predator–prey behavioural interactions drive predation risk.
1. Introduction
The fact that predators can only kill prey when they overlap in space and time [1]
has led to the belief that increased spatial [2,3] and temporal [4,5] overlap
between predators and prey correlates with predation risk. For example, diel
activity overlap between predator and prey is now increasingly used as a
proxy of predation risk [6–8]. However, although this may be a reasonable start-
ing assessment of perceived predation risk (e.g. high predator density or places
and times where and when predators are more likely to be present and active),
such overlap may not always be a good proxy of actual predation risk (the prob-
ability of predation). Assessment of predation risk in relation to behavioural
predator–prey interactions requires simultaneous measures of the behaviour of
predator and prey and predation rate, but such studies are still scarce (but see [9]).
Effects of predator–prey spatio-temporal overlap on predation can be
confounded by various environmental factors. For example, habitat character-
istics are potentially more important determinants of predation than
predator–prey spatial overlap [10], or diel patterns of predation can be modified
by anthropogenic disturbance while prey fail to adjust their temporal activity
pattern in response to it [11]. It is well documented that prey show a wide
© 2023 The Author(s) Published by the Royal Society. All rights reserved.
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