Starting with the basics: biology and European distribution of the fig weevil Aclees taiwanensis

The fig weevil, Aclees taiwanensis Kôno, 1933 (Coleoptera: Curculionidae), is an alien species native to Taiwan, detected for the first time in Europe in 2005 (Tuscany, Italy). It feeds and develops only on plants belonging to the genus Ficus, threatening the Mediterranean production of the common fig Ficus carica. Adults eat buds, leaves, and ripening infructescences, and the xylophagous larvae dig feeding galleries in the wood of trunk and surface roots, slowly bringing the attacked trees to death. Despite its harmfulness, data about the biology, physiology, and distribution of this pest were scarce. Therefore, this work aimed to verify, under laboratory conditions, the duration of all the A. taiwanensis developmental stages (embryonic, larval, and pupal), the oviposition modality and the mean number of eggs laid by each female, the eggs’ hatching percentage, and the instars and adults’ morphometric measures. Also, we evaluated the susceptibility of three Ficus ornamental species of economic importance (F. benjamina, F. macrocarpa, and F. pandurata). Moving to the field, we registered the presence peaks during 2019 and 2020 using mechanical traps wrapped around the fig plants to catch the adults. In the end, surveying the social networks and naturalistic forums through a citizen science approach, we verified the European distribution of A. taiwanensis that currently includes seven northern and central Italian regions and one French region. The new information provided could help to develop innovative and focused management strategies to avoid the further spread and menace of the fig weevil.