Variation in resource utilization plays a significant role in determining the success or failure of a species. Generalist species across numerous taxa have exhibited success in feeding strategies for a variety of reasons. This study investigated the colonization and oviposition habits of a generalist carrion-feeder, Hermetia illucens L. (Diptera: Stratiomyidae), to varying conditions of carrion decay and colonization. Oviposition treatments consisted of combinations of variably aged decaying rats, both uncolonized and colonized with a heterospecific carrion-feeder.The black soldier fly exhibited a greater preference for oviposition on aged carrion, regardless of carcass colonization status. However, when presented with the option to colonize a plant-based diet, there was a significantly greater (40.4%) oviposition response to this diet. Results of this study highlight the ability of the black soldier fly to colonize fresh or aged carrion with or without a primary colonizer present, further supporting the recognition of this species as a generalist.These data demonstrate potential inaccuracies in the utility of H. illucens as time of colonization indicator species for legal investigations, and, in some regard, can be considered an exploitative niche-specialist (i.e., relying on plant–carrion interface for immature development) when found in association with carrion.