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The influence of predator regime on reproductive traits in Gammarus pulex populations

Åbjörnsson, Kajsa LU ; Brönmark, Christer LU and Hansson, Lars-Anders LU (2009) In Hydrobiologia 635(1). p.215-225
Abstract
Selection on traits conferring reduced predation may be opposed by selection on other traits associated with reproduction. Here, we examined the hypothesis that traits associated with reproduction in Gammarus pulex are driven by predation. We studied G. pulex originating from ponds with two different kinds of predator regimes: (1) ponds with fish-often large, non-gap-limited predators and (2) ponds without fish where invertebrates are the dominant predators-often small, gap-limited predators with a much more restricted prey size range. We examined the body size of males and females in G. pulex amplexus pairs originating from fish and fishless ponds. We also examined, in the laboratory, their mating success, the number of offspring per... (More)
Selection on traits conferring reduced predation may be opposed by selection on other traits associated with reproduction. Here, we examined the hypothesis that traits associated with reproduction in Gammarus pulex are driven by predation. We studied G. pulex originating from ponds with two different kinds of predator regimes: (1) ponds with fish-often large, non-gap-limited predators and (2) ponds without fish where invertebrates are the dominant predators-often small, gap-limited predators with a much more restricted prey size range. We examined the body size of males and females in G. pulex amplexus pairs originating from fish and fishless ponds. We also examined, in the laboratory, their mating success, the number of offspring per female and offspring mortality under different rearing conditions, with or without fish cue. Mating success, defined as the percentage of amplexus pairs that produced live offspring, was higher for G. pulex from fishless ponds independent of rearing condition. Individuals from fish ponds were larger and they produced a higher number of offspring which tended to be related to female body size. Offspring mortality was higher in populations from fish ponds compared to populations from fishless ponds. Despite the higher offspring mortality, females from fish ponds had a higher number of offspring alive after 13 weeks, which is the approximate time it takes for G. pulex to reach maturity. Our data imply that no trade-off between reducing body size to reduce mortality caused by fish and maximising reproductive success exist in G. pulex from fish ponds. The strategy with many offspring may be the correct strategy in fishponds where predation pressure generally is higher than in fishless ponds. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Predator regime, Reproduction, Gammarus pulex, Fish, Life history
in
Hydrobiologia
volume
635
issue
1
pages
215 - 225
publisher
Springer
external identifiers
  • wos:000270652200020
  • scopus:70350399947
ISSN
0018-8158
DOI
10.1007/s10750-009-9914-6
language
English
LU publication?
yes
id
43d90a0e-2384-440d-9b5c-95f97b1fa7c1 (old id 1507387)
date added to LUP
2009-11-20 14:24:29
date last changed
2017-01-01 04:32:46
@article{43d90a0e-2384-440d-9b5c-95f97b1fa7c1,
  abstract     = {Selection on traits conferring reduced predation may be opposed by selection on other traits associated with reproduction. Here, we examined the hypothesis that traits associated with reproduction in Gammarus pulex are driven by predation. We studied G. pulex originating from ponds with two different kinds of predator regimes: (1) ponds with fish-often large, non-gap-limited predators and (2) ponds without fish where invertebrates are the dominant predators-often small, gap-limited predators with a much more restricted prey size range. We examined the body size of males and females in G. pulex amplexus pairs originating from fish and fishless ponds. We also examined, in the laboratory, their mating success, the number of offspring per female and offspring mortality under different rearing conditions, with or without fish cue. Mating success, defined as the percentage of amplexus pairs that produced live offspring, was higher for G. pulex from fishless ponds independent of rearing condition. Individuals from fish ponds were larger and they produced a higher number of offspring which tended to be related to female body size. Offspring mortality was higher in populations from fish ponds compared to populations from fishless ponds. Despite the higher offspring mortality, females from fish ponds had a higher number of offspring alive after 13 weeks, which is the approximate time it takes for G. pulex to reach maturity. Our data imply that no trade-off between reducing body size to reduce mortality caused by fish and maximising reproductive success exist in G. pulex from fish ponds. The strategy with many offspring may be the correct strategy in fishponds where predation pressure generally is higher than in fishless ponds.},
  author       = {Åbjörnsson, Kajsa and Brönmark, Christer and Hansson, Lars-Anders},
  issn         = {0018-8158},
  keyword      = {Predator regime,Reproduction,Gammarus pulex,Fish,Life history},
  language     = {eng},
  number       = {1},
  pages        = {215--225},
  publisher    = {Springer},
  series       = {Hydrobiologia},
  title        = {The influence of predator regime on reproductive traits in Gammarus pulex populations},
  url          = {http://dx.doi.org/10.1007/s10750-009-9914-6},
  volume       = {635},
  year         = {2009},
}