Invasive alien species (IAS) are a major biosecurity threat affecting globalisation and the international trade of agricultural products and natural ecosystems. In recent decades, for example, field crop and postharvest grain insect pests have independently accounted for a significant decline in food quantity and quality. Nevertheless, how their interaction and cumulative effects along the ever-evolving field production to postharvest continuum contribute towards food insecurity remain scant in the literature. To address this within the context of Africa, we focus on the fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), and the larger grain borer, Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae), two of the most important field and postharvest IAS, respectively, that have invaded Africa. Both insect pests have shown high invasion success, managing to establish themselves in >50% of the African continent within a decade post-introduction. The successive and summative nature of field and postharvest damage by invasive insect pests on the same crop along its value chain results in exacerbated food losses. This systematic review assesses the drivers, impacts and management of the fall armyworm and larger grain borer and their effects on food systems in Africa. Interrogating these issues is important in early warning systems, holistic management of IAS, maintenance of integral food systems in Africa and the development of effective management strategies.

Climate change is associated with increased mean temperatures and amplitudes manifesting both acutely and chronically, triggering organism stress responses that confer fitness costs and/or benefits. The larger grain borer (LGB), Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae) is an invasive postharvest agricultural pest. While host shift is its well‐known potential invasive mechanism, how repeated intergenerational stress environments may influence offspring phenotypes is largely unknown. We thus evaluated physiological and ecological performance of LGB following repeated intergenerational acute heat acclimation to insinuate its likely responses to projected increased bouts of heat stress associated with climate change. Parental colonies were acutely heat‐acclimated separately at 35°C and 38°C; 80% RH for 2 h in climate chambers and released onto sterilized maize grain at optimal conditions (32°C, 80% RH). The F ₁ progenies were, respectively, acclimated at the same conditions and incubated to F ₂ generation. We then evaluated physiological and ecological performance under optimal conditions across parental, F ₁ and F ₂ generations. Our results showed that plasticity was highly trait dependent, and that acclimation did not affect F ₁ and F ₂ critical thermal maxima, but did improve critical thermal minima. However, while acclimation improved heat knockdown time at F ₁ , repeated acclimation significantly reduced heat knockdown times at F ₂ , suggesting plasticity erosion with generational repeated acclimations. Acute acclimation negatively affected ecological performance of F ₁ generations although this was restored with repeated acclimation in F ₂ populations. Our results suggest that the LGB may inflict more economic damage with repeated heat stress due to generational adaptation to temperature stress. The results contribute to knowledge on pest forecasting modelling under changing climates and provides a framework for phytosanitary adjustments in heat treatment protocols for international grain trade.