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Does risk of intraspecific interactions induce shifts in prey-size preference in aquatic: predators?

Nilsson, Anders LU ; Nilsson, K and Nyström, Per LU (2000) In Behavioral Ecology and Sociobiology 48(4). p.268-275
Abstract
Interactions between foragers may seriously affect individual foraging efficiency. In a laboratory study of handling time, prey value and prey-size prefer ence in northern pike and signal crayfish, we show that risk of intraspecific interactions between predators does not affect handling time or value of prey. However, the presence of agonistic intraspecific interactors shifts prey-size preference in these predators. Neither northern pike nor signal crayfish foraging alone show a prey-size preference, while pike foraging among conspecifics prefer small prey, and crayfish foraging in groups prefer large prey. We ascribe the different outcomes in prey preference to differences in susceptibility to interactions: northern pike under risk avoid... (More)
Interactions between foragers may seriously affect individual foraging efficiency. In a laboratory study of handling time, prey value and prey-size prefer ence in northern pike and signal crayfish, we show that risk of intraspecific interactions between predators does not affect handling time or value of prey. However, the presence of agonistic intraspecific interactors shifts prey-size preference in these predators. Neither northern pike nor signal crayfish foraging alone show a prey-size preference, while pike foraging among conspecifics prefer small prey, and crayfish foraging in groups prefer large prey. We ascribe the different outcomes in prey preference to differences in susceptibility to interactions: northern pike under risk avoid large prey to avoid long handling times and the associated risk of interactions, while signal crayfish foraging among conspecifics may defend themselves and their prey during handling, and thus select prey to maximise investment. In addition, the value of pike prey (roach) is low for very small prey, maximises for small prey, and then decreases monotonically for larger prey, while crayfish prey (pond snail) value is low for very small prey, has a maximum at small prey, but does not decrease as much for larger prey. Therefore, a large and easily detected snail prey provides a crayfish with as much value as a small prey. We conclude that interaction risk and predator density affect prey-size preference differently in these aquatic predators, and therefore has different potential effects on prey-size structure and population and community dynamics. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Behavioral Ecology and Sociobiology
volume
48
issue
4
pages
268 - 275
publisher
Springer
external identifiers
  • scopus:0033824525
ISSN
1432-0762
DOI
10.1007/s002650000235
language
English
LU publication?
yes
id
f440350e-d018-4d11-a489-aadbd13cf072 (old id 146708)
date added to LUP
2007-06-28 15:36:19
date last changed
2017-07-02 03:33:53
@article{f440350e-d018-4d11-a489-aadbd13cf072,
  abstract     = {Interactions between foragers may seriously affect individual foraging efficiency. In a laboratory study of handling time, prey value and prey-size prefer ence in northern pike and signal crayfish, we show that risk of intraspecific interactions between predators does not affect handling time or value of prey. However, the presence of agonistic intraspecific interactors shifts prey-size preference in these predators. Neither northern pike nor signal crayfish foraging alone show a prey-size preference, while pike foraging among conspecifics prefer small prey, and crayfish foraging in groups prefer large prey. We ascribe the different outcomes in prey preference to differences in susceptibility to interactions: northern pike under risk avoid large prey to avoid long handling times and the associated risk of interactions, while signal crayfish foraging among conspecifics may defend themselves and their prey during handling, and thus select prey to maximise investment. In addition, the value of pike prey (roach) is low for very small prey, maximises for small prey, and then decreases monotonically for larger prey, while crayfish prey (pond snail) value is low for very small prey, has a maximum at small prey, but does not decrease as much for larger prey. Therefore, a large and easily detected snail prey provides a crayfish with as much value as a small prey. We conclude that interaction risk and predator density affect prey-size preference differently in these aquatic predators, and therefore has different potential effects on prey-size structure and population and community dynamics.},
  author       = {Nilsson, Anders and Nilsson, K and Nyström, Per},
  issn         = {1432-0762},
  language     = {eng},
  number       = {4},
  pages        = {268--275},
  publisher    = {Springer},
  series       = {Behavioral Ecology and Sociobiology},
  title        = {Does risk of intraspecific interactions induce shifts in prey-size preference in aquatic: predators?},
  url          = {http://dx.doi.org/10.1007/s002650000235},
  volume       = {48},
  year         = {2000},
}