Insect Herbivory Research in Africa Is Limited and Fragmented

Abstract

Insect herbivory plays a critical role in shaping plant growth, fitness, and population dynamics, yet its effects across African ecosystems remain poorly understood due to fragmented, methodologically diverse, and geographically biassed research. To address this gap, we conducted an integrated bibliometric and systematic review of peer-reviewed studies on insect herbivory and plant performance in Africa. Searches of Web of Science and Scopus identified 1642 records, of which 312 met relevance criteria and 157 satisfied quality thresholds, including clear herbivory metrics and robust experimental or observational designs. Bibliometric analyses revealed modest but increasing publication rates, with research concentrated in Southern and Eastern Africa and primarily focused on savannas and agroecosystems. Montane forests, wetlands, and arid ecosystems remain underrepresented. Most studies examined Lepidopteran leaf herbivory, while fewer than 15% addressed root, stem, or seed damage, and research collaborations were largely regional. Systematic synthesis showed that insect herbivory generally reduces seedling survival, height, and biomass, particularly at early life stages, although some species display tolerance or compensatory growth depending on environmental conditions and plant traits. Reported effect sizes were highly variable (Hedges’ g = 2.1–3.4), reflecting differences in ecological context, herbivore guilds, and study design. Few studies incorporated multiple life stages, trophic interactions, or climate gradients, limiting inference on long-term population and ecosystem responses. We emphasise the need for harmonised methodologies, trait-based and guild-specific approaches, long-term manipulative studies, and expanded research across underrepresented ecosystems to better inform conservation and restoration under environmental change.