2008/10/15 by Ryan Calsbeek · 1 citation
Agricultural and Biological Sciences · Environmental Science · #Animal Behavior and Reproduction #Plant and animal studies #Fish Ecology and Management Studies #Intraspecific competition #Biology #Natural selection #Anolis #Competition (biology) #Ecology #Selection (genetic algorithm) #Habitat #Stabilizing selection #Population density #Perch #Population #Fishery
paper · doi:10.1111/j.1420-9101.2008.01625.x
openalex publication_date 2008/10/15 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/29
A key prediction made by theories of density-dependent competition is that resource overlap should increase the intensity of competition. By extension, we can predict that competition should lead to density-dependent natural selection. I studied natural selection on limb length and body size in a total of seven populations of Anolis sagrei over 3 years in the Bahamas. Experimental manipulations of population density on small off-shore cays revealed that the strength of natural selection on body size increased with density, suggesting that density-dependent intraspecific competition drives natural selection. At low density, reduced competition revealed significant selection on limb length driven by changes in perch diameter, indicating that selection favoured a match between morphology and habitat. The role habitat played in shaping selection was further illuminated by inter-annual changes in vegetation structure stemming from variation in precipitation among years. Thus, changes in both the intensity of competition across spatial replicates, and in resource availability through time, revealed changes in the targets of natural selection. Results provide empirical support for the long-standing hypothesis that density-dependent natural selection shapes the fitness surface of Greater Antilles anoles.