This dissertation reports the results from 6 years of field and laboratory reseach on the ecology of defense of a host insect species against parasitic wasps. The focus of this research was to understand the influence of host (or prey) traits on two specific stages of a successful parasitism (or predation) sequence: detection and attack. The overarching question was: "Can there be a fitness trade-off between these stages?" More specifically, this work quantified the costs and benefits of being in a group, and the shapes of the benefit or cost functions in association with variable environmental and social conditions. The general results of this work suggest that there is a trade-off between avoiding detection and escaping attack. However, if alternative strategies and selection pressures are considered, then any potential fitness costs of increased vulnerability at early stages may be offset by other traits and individual behaviors. This dissertation reports the costs of visual detection risk, the behavioral defenses of an individual, the costs and benefits of group living, and selection on female oviposition behavior.