Seasonal activity, host interaction and morphometric analysis of the invasive Scyphophorus acupunctatus (Coleoptera: Dryophthoridae) in a mediterranean botanic garden

The agave weevil Scyphophorus acupunctatus is an invasive alien species native to Central America. Its phenology and impacts are well documented in its native area, where it severely damages agave monocultures. Limited information exists regarding its ecology in the Mediterranean Basin, even though it is increasingly found in botanical collections and semi-natural habitats. Understanding how this pest behaves in multi-host environments is essential for assessing its impact and designing effective pest management strategies. The work was conducted in the Hanbury Botanic Gardens (Italy), a historic acclimatization garden hosting a very diverse Agavaceae collection. Monitoring reveals that the weevil is active year-round, showing two seasonal peaks similar to those reported in Mexico. Visual observations, phytosanitary eradications and biometric measurements indicate clear differences in host use: although the weevil is polyphagous, it has been found, feeding and reproducing on specific taxa, while others are rarely used or attacked. These differences may reflect variation in host nutritional quality, structural traits, and physiological requirements of the insect. Morphometric analyses revealed a sexual size dimorphism, with males larger than females. Body–size allometry indicated isometric growth, and the calculated Body Condition Index suggests that the studied population is in good physiological state, supporting the species’ successful adaptation to Mediterranean conditions. Overall, these findings provide the first integrated assessment of S. acupunctatus in a Mediterranean multi-host system and offer a baseline for evaluating host susceptibility and designing management strategies.