Blister beetles (Coleoptera: Meloidae) exhibit an exceptionally specialized form of insect host exploitation that integrates chemical deception, phoretic transport, and extreme life-cycle specialization. In several meloid lineages, first-instar larvae manipulate the behaviour of solitary bees by producing chemical signals that closely mimic host pheromonal cues, inducing attraction, mounting, and transport by adult bees. This phoretic phase represents a critical developmental bottleneck, as mortality is concentrated almost entirely before nest entry. Once transported into the nest environment, larvae undergo rapid ontogenetic transitions from mobile, host-seeking triungulins to sedentary instars specialized for feeding. They initially consume pollen provisions and subsequently prey upon bee eggs or larvae, resulting in complete brood loss within affected cells. Although infestation prevalence varies among host species and nesting contexts, the ecological impact at the nest level is severe, highlighting blister beetles as strong selective agents acting on bee life-history traits and nesting strategies. In addition to deceptive signalling, blister beetles produce a cardioactive defensive compound that is concentrated in post-phoretic developmental stages and enhances larval survival within the nest by protecting against predators and microbial threats. The temporal separation of deceptive and defensive chemical functions illustrates how multiple traits are integrated into a coherent life-history strategy. By synthesizing classical natural history with recent analytical and comparative studies, this work positions the blister beetle–bee interaction as a powerful model for investigating the evolution of dishonest signalling, host manipulation, and multifunctional chemical traits in insects.