What common trait do adult flesh flies share?

Adult flesh flies are commonly associated with feeding on decomposing organic matter. This behavior is particularly important in their ecological role, as they help in the breakdown of dead animals and other decaying substances. This trait is significant because it not only supports their nutrient requirements for reproduction but also aids in the process of decomposition, contributing to nutrient cycling within ecosystems.

While other options may describe certain characteristics of different insects, they do not apply to adult flesh flies. For example, while some insects may have a metallic sheen, it is not a defining trait of flesh flies. Similarly, the aggression levels or silk production mentioned in the other options do not pertain to adult flesh flies. Thus, the correct answer focuses on their role as scavengers and their dietary habits related to decomposing matter.