Foraging syndromes and trait variation in antlions along a climatic gradient.

Behavioral syndromes arise when individual behavior is correlated over time and/or across environmental contexts, often resulting in inter-population behavioral differences. Three main hypotheses have been suggested to explain the evolution of behavioral syndromes. The constraint hypothesis suggests that behaviors originate from a shared mechanism with a strong genetic or physiological basis. In contrast, according to the adaptive hypothesis, behavioral syndromes depend on specific selective pressures in each environment, and thus should evolve when specific behavioral combinations are advantageous. Finally, behavioral syndromes can also arise owing to neutral stochastic processes. We tested here for variation in the foraging syndromes of pit-building antlions originating from different populations along a climatic gradient. Although inter-population variation existed in some traits, foraging syndromes were similar across populations, supporting the constraint hypothesis. These findings suggest that stabilizing selection, acting on the foraging behavior of antlions during their larval phase, outweighs local selection pressures, resulting in "constraint syndromes." We also explored behavioral repeatability of foraging-related traits within and among habitats (natural, novel and disturbed habitats), and detected different levels of repeatability: pit diameter was more repeatable than response time to prey, followed by prey exploitation efficiency. Behavioral repeatability of the same trait differed according to context, suggesting that repeatability is a trait in itself and should not be considered identical even when studying the same behavioral trait.