Colonization across gradients of risk and reward: nutrients and predators generate species-specific responses among aquatic insects

1. Predation risk and resource abundance are two primary characteristics that determine species abundances and community composition. Colonizing organisms should attempt to minimize the risk of mortality and maximize growth through selection of patches with the highest expected fitness. However, maximizing fitness across multiple gradients of patch quality involves accurate cue assessment, integration, and behavioral responses that consider multiple factors that affect fitness simultaneously.
2. Our goal was to simultaneously and factorially assess the effects of predation risk and resource abundance among an assemblage of aquatic insects to determine the relative importance of each factor, and whether the two factors interact to affect colonization, oviposition, and community assembly.
3. We conducted a field mesocosm experiment in which we crossed predator density (0, 1, 2 fish, Fundulus chrysotus) with supplemental nutrient abundance (0, 4, 8 g rabbit chow) in a 3 × 3 factorial des...