Appearance
Archarius salicivorus is a relatively small (1.8-2.8mm), black weevil with a mostly white belly. The spaces between the rows of punctures on the elytra are much wider than those same rows and carry 2-3 rows of white hairs each.The slightly smaller (<2.4mm) Archarius pyrrhoceras, developing on Oak, has the interspaces only slightly wider with 1-2 rows of hairs on each.
Naming
This species has long been classified in the genus Curculio and some references may hence still sport it as Curculio salicivorus. The species Curculio brassicae Fabricius, 1792 and Curculio pedemontanus Fuchs, 1862 are today considered objective synonyms.Reproduction
The larvae develop in the galls of sawflies where these feed on the gall tissue, usually winning this competition for food with the sawfly larva dying off, but not being eaten by the weevil larva (unlike in the case of A. crus with similar development). The mature larva bores an exit hole out of the gall and drops to the floor, where it pupates under fallen leafs or at shallow depth in the soil. There are two generations each year with the adult beetles of the second generation overwintering.References:
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