Authors: Gazzea, Elena; Batáry, Péter;Marini, Lorenzo;

Insect pollination directly benefits the reproduction of a wide share of crops. Despite the importance of pollinators in contributing to global food security and health, much of the research has focused on quantifying their contribution to crop yield, while a comprehensive assessment of their role in enhancing food quality is still lacking. We focused on investigating the effects of the pollination service provided by insects on crop quality by applying a systematic literature review, and by summarising relevant studies through a set of multi-level meta-analyses. We included 112 articles studying the effects of pollination, and extracted over 800 effects sizes about more than 30 different crops worldwide. Results indicate that pollinating insects significantly contribute to increasing quality of all crop types. Physical attributes, such as crop size, shape, and commercial grade significantly improve with pollination, while nutritional and biochemical composition does not seem to be affected. The positive effects on crop quality were observed independently of pollinator species, biome and methodological approach. Our results highlight the need for implementing pollinator conservation and management actions, to ensure crop quality and improve food marketability.