Chemical communication in insects is often described as if signal production, environmental transmission, detection, neural processing, and behavioral response formed one continuous and self-evident causal chain. Evidence across insect taxa instead shows that each transition has distinct biological constraints and distinct evidential requirements. This integrative review examines how chemical signals are generated, released into heterogeneous environments, detected by peripheral chemosensory systems, and transformed by higher-order neural processing before contributing to behavior. The synthesis emphasizes three recurring sources of interpretive error: inferring behavioral meaning from receptor responsiveness, generalizing laboratory signal delivery to natural odor landscapes, and treating context-dependent responses as fixed properties of compounds. A proposed inferential architecture therefore separates production, environmental availability, peripheral detectability, neural interpretation, and behavioral use while retaining taxonomic, life-stage, environmental, and methodological boundaries. This separation clarifies why the same chemical can participate in different ecological relationships and why similar behavioral outcomes can emerge from different sensory-processing routes. The resulting framework is intended as an evidence-bounded guide for integrating molecular, neurobiological, behavioral, and ecological studies rather than as a universal mechanistic model.
