Perceived risk of predation affects reproductive life-history traits in Gambusia holbrooki, but not in Heterandria formosa

PLoS One. 2014 Feb 13;9(2):e88832. doi: 10.1371/journal.pone.0088832. eCollection 2014.


Key to predicting impacts of predation is understanding the mechanisms through which predators impact prey populations. While consumptive effects are well-known, non-consumptive predator effects (risk effects) are increasingly being recognized as important. Studies of risk effects, however, have focused largely on how trade-offs between food and safety affect fitness. Less documented, and appreciated, is the potential for predator presence to directly suppress prey reproduction and affect life-history characteristics. For the first time, we tested the effects of visual predator cues on reproduction of two prey species with different reproductive modes, lecithotrophy (i.e. embryonic development primarily fueled by yolk) and matrotrophy (i.e. energy for embryonic development directly supplied by the mother to the embryo through a vascular connection). Predation risk suppressed reproduction in the lecithotrophic prey (Gambusia holbrokii) but not the matrotroph (Heterandria formosa). Predator stress caused G. holbrooki to reduce clutch size by 43%, and to produce larger and heavier offspring compared to control females. H. formosa, however, did not show any such difference. In G. holbrooki we also found a significantly high percentage (14%) of stillbirths in predator-exposed treatments compared to controls (2%). To the best of our knowledge, this is the first direct empirical evidence of predation stress affecting stillbirths in prey. Our results suggest that matrotrophy, superfetation (clutch overlap), or both decrease the sensitivity of mothers to environmental fluctuation in resource (food) and stress (predation risk) levels compared to lecithotrophy. These mechanisms should be considered both when modeling consequences of perceived risk of predation on prey-predator population dynamics and when seeking to understand the evolution of reproductive modes.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Bass / physiology
  • Biological Evolution
  • Clutch Size
  • Cyprinodontiformes / physiology*
  • Female
  • Food Chain
  • Killifishes / physiology*
  • Population Dynamics
  • Predatory Behavior / physiology
  • Reproduction*
  • Risk
  • Stress, Psychological*

Grant support

SM was supported by School of Environment, Arts and Society. Publication of this article was funded in part by Florida International University Open Access Publishing Fund. This material was developed in collaboration with the Florida Coastal Everglades Long-Term Ecological Research program under National Science Foundation Grant No. DBI-0620409. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.