Reznick's Guppies

  1. Who: biologists David Reznick (UC-Riverside) and John Endler (UC-Santa Barbara).
  2. What: Studied several populations of guppies (Poecilia reticulata).
  3. Where: Small pools in streams in Trinidad.
  4. Findings:
    1. Populations are isolated, some by small waterfalls.
    2. Populations in different streams had differences in life histories.
      • Guppy Population 1
        • Mature slowly
        • Adults larger
        • Mate later
        • Mate less often
        • Have fewer offspring
        • Upstream environment
        • killifish predators
      • Guppy Population 2
        • Mature quickly
        • Adults smaller
        • Mate earlier
        • Mate more often
        • Have more offspring
        • Downstream environment
        • pike-cichlids predators

Their observations raised two questions:

  1. Are differences in guppy population life histories due to physical environment?
  2. Are differences in guppy population life histories due to feeding preferences of the predators?

Your task

Design an experiment to answer one of those questions.