Environmental conditions experienced during immature insect stages can alter later phenotypes, yet the meaning of those effects is often obscured by treating developmental plasticity, persistent damage, developmental memory, recovery, compensation, and adult fitness as interchangeable outcomes. This umbrella review evaluates cross-stage responses to thermal change, nutritional limitation and drought, and pollution or chemical exposure, with emphasis on how effects are retained, redirected, attenuated, or expressed after developmental transitions. Across the evidence base, global-change responses were strongly endpoint-, stage-, taxon-, and context-dependent. Thermal exposure altered developmental rates and physiological limits but did not consistently translate into beneficial adult performance. Nutritional and drought effects depended on exposure severity, host-mediated pathways, trophic context, and reproductive physiology, while null and heterogeneous carry-over effects remained important. Pollution evidence showed broad organismal toxicity but substantially stronger inference when developmental exposure was directly linked to later reproductive impairment. We therefore distinguish developmental memory from any persistent phenotype and reserve compensation for cases in which a later response offsets, rather than merely follows, an earlier cost. The emerging synthesis treats cross-stage plasticity as a conditional trajectory whose adult consequences depend on developmental gating, environmental matching, recovery capacity, endpoint choice, and scale of inference. This framework is proposed as an evidence-organizing architecture rather than a validated universal mechanism.
