Developmental stability and predation success in an insect predator-prey system

I investigated the relationships among developmental stability (as measured by individual bilateral asymmetry values), two measures of locomotory performance and predation success in an insect predator-prey system. In this system yellow dungflies Scathophaga stercoraria preyed upon houseflies Musca domestica in laboratory-controlled conditions. There was no relationship between locomotion and absolute asymmetry or mean size of two morphological traits (fourth longitudinal wing vein, foreleg tibia) in either species. Analysis of single predation trials indicated that locomotion performance and trait size are not associated with the probability of predation. However, Musca that were captured had tibia that were more asymmetric than Musca that survived. Similarly, Scathophaga that were successful predators had more symmetric forelegs than unsuccessful predators. There was no relationship between predation and wing vein asymmetry, which may indicate the importance of terrestrial-based predatory avoidance tactics in this system. There were no relationships between morphology or locomotion with predation latency, prey handling times, or the number of times a prey ''escaped'' from a predator. The mechanisms behind the relationship between tibia asymmetry and predation success are discussed. This is the first experiment to reveal direct evidence for selection for symmetric, developmentally stable individuals through differential predation.