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Host specificity of phytophagous insects plays a critical role in the maintenance of plant diversity. However, a lack of approaches to identify the larvae of phytophagous insects, which usually have similar morphology, can lead to misinterpretation of their host ranges.Acorn weevils are seed‐exploiting parasites of Fagaceae species, a dominant plant group in subtropical evergreen broad‐leaved forests (EBLFs). Therefore, variation in their host specificity may profoundly influence plant diversity in this ecosystem.Here, we collected larvae of acorn weevils from 36 655 seeds of Fagaceae species in EBLFs in southeastern China and performed multiple operational taxonomic unit (OTU) delimitation analyses using one mitochondrial (COI) and two nuclear (ArgK and EF1‐α) genes to reveal species composition of acorn weevils and assess the variation in host specificity among OTUs.We analysed the DNA barcoding sequences from 478 larvae and 4 adults of acorn weevils sampled from 17 common Fagaceae species (five genera) and detected 11 OTUs. Moreover, host range varied drastically among different OTUs, with Curculio bimaculatus being the most generalised.Our results revealed high diversity of acorn weevils and that strong variation in host specificity can even exist among OTUs in the same genus, addressing the need to distinguish different Curculio species before conducting forest management in EBLFs. [ABSTRACT FROM AUTHOR]

Abstract: Revealing the host specificity of the predators/parasitoids of invasive species is a prerequisite when assessing the suitability of biocontrol agents, while the host ranges of top predators are likely to vary among communities comprising different species. Ficus microcarpa is a native plant in Asia and Australasia and has invaded in sometropical and subtropical areas. Besides its species‐specific pollinator, its figs also support many ovule‐galling and parasitoid non‐pollinating fig wasps. Here, based on a global collection of fig wasps associated with F. microcarpa figs, we used path analysis, supplemented by within‐fig spatial distributions and natal gall sizes to reveal food web structure of its associated fig wasps and the factors forming host ranges of parasitoids. The fig wasp community was species‐rich, and parasitoids were far rarer in the plant's introduced range. Parasitoids exhibited some host specificity, and four specific natural enemies of the plant's pollinator were identified with various intensities of effects on pollinator abundance. Parasitoid host ranges were consistent in both ranges of the plant, and mainly restricted by the size and the locations of host galls. No parasitoids were found associated with a unique seed predator. Our results showed how a large number of fig wasp species partition one host fig tree's figs and identified the species that have potential to control the sexual reproduction of F. microcarpa. [ABSTRACT FROM AUTHOR]

The transportation of plants and insects between countries often has negative consequences, but also provides opportunities to study community processes. Fig trees are a species-rich group of largely tropical and subtropical plants, characterised by their unusual inflorescences (figs)., Ficus microcarpa is a native of Asia and Australasia and frequently planted elsewhere. Widespread introductions of its pollinator fig wasp, Eupristina verticillata, have allowed the tree to reproduce and become increasingly invasive. Non-pollinating fig wasps ( NPFW) are also widely introduced., Here, we combine previously published records of the distributions of fig wasps associated with F. microcarpa with the results of our extensive surveys across much of its introduced and native ranges. At least 43 morpho-species of fig wasps are associated with figs of F. microcarpa, most of which have only been recorded from this host. Twenty-one NPFW have become established outside their native ranges, but there has been only limited colonisation by locally native fig wasps within countries of introduction., Fig wasp communities in colonised areas are less species-rich and contain a lower proportion of parasitoids. The pollinator and two phytophagous NPFW are the most widely introduced species, and usually the first species to arrive in countries where the host fig has become established. The pace of colonisation appears to be accelerating., The rarity of faunal acquisition on introduced F. microcarpa contrasts strongly with that of introduced gall wasps on oaks and chestnuts. [ABSTRACT FROM AUTHOR]