Environmental drivers of body size plasticity and their consequences for reproductive fitness in Anopheles coluzzii

Malaria is a life-threatening infectious disease caused by Plasmodium parasites and transmitted to humans primarily through the bites of infected female Anopheles mosquitoes. Sub-Saharan Africa bears the greatest global burden of malaria, with members of the Anopheles gambiae complex, including Anopheles coluzzii, serving as important malaria vectors in the region. This review synthesises current evidence on environmental factors influencing body size in An. coluzzii, the potential consequences of body-size variation for reproductive and life-history traits, and key knowledge gaps requiring further investigation. A systematic literature search was conducted using Google Scholar, ScienceDirect, and Scopus to identify original research articles published in English between 2000 and February 2026. Following the predefined selection criteria, 103 articles were included in the review. The available evidence indicates that larval nutrition and density, temperature, predation risk, larval habitat characteristics and water quality, and seasonal variation can influence adult body size. Wing length is the most commonly used morphological proxy for adult body size and has been associated with measures of dry mass and energetic reserves in some studies; however, its ability to reliably represent physiological condition or overall fitness is context-dependent. In females, larger body size has generally been associated with greater fecundity, increased blood-meal volume, and, under some environmental conditions, enhanced survival, although these relationships are not universal. In males, body size may influence mating-related traits, including acoustic signalling and mating success, but the strength and direction of these relationships vary among studies and ecological contexts. Overall, the effects of environmental conditions on mosquito body size are interactive and depend on resource availability, developmental conditions, population density, and ecological context. Important knowledge gaps remain in establishing consistent relationships between morphological measures, physiological condition, reproductive performance, and population dynamics under natural field conditions.