Weevils as Targets for Biological Control, and the Importance of Taxonomy and Phylogeny for Efficacy and Biosafety

Abstract

Curculionidae are a large mainly herbivorous family of beetles, some of which have become crop pests. Classical biological control has been attempted for about 38 species in 19 genera, and at least moderate success has been achieved in 31 % of cases. Only two weevil species have been considered to be completely controlled by a biological control agent. Success depends upon accurately matching natural enemies with their hosts, and hence taxonomy and phylogeny play a critical role. These factors are discussed and illustrated with two case studies: the introduction of the braconid parasitoid Mictroctonus aethiopoides into New Zealand for biological control of the lucerne pest Sitona discoideus, a case of complex phylogenetic relationships that challenged the prediction of potential non-target hosts, and the use of a mymarid egg parasitoid, Anaphes nitens, to control species of the eucalypt weevil genus Gonipterus, which involves failure to match up parasitoids with the right target amongst a complex of very closely related species. We discuss the increasing importance of molecular methods to support biological control programmes and the essential role of these emerging technologies for improving our understanding of this very large and complex family.

Gonipterus (Coleoptera: Curculionidae) in subtropical Australia: host associations and natural enemies

“…Interest in the potential of tachinids as biocontrol agents of Gonipterus has recently increased (Afonso et al ., 2018; Gonçalves et al ., 2020), as targeting the larvae can potentially augment the biocontrol programmes (Schröder et al ., 2019). However, further studies are necessary to establish the host associations of these parasitoids, given the taxonomic complexity of their host weevils (Barratt et al ., 2018), non‐target parasitism and also to identify possible hyperparasitism, as such likely cases have been found in our study and in previous work (Loch, 2008).…”

“…These studies and previous ones conducted in the native range of Gonipterus focused on south‐eastern Australia including Tasmania (Tooke, 1955; Clarke et al ., 1998; Valente et al ., 2017), where the climate is predominantly temperate (Commonwealth of Australia, 2005), whereas subtropical Australia has been neglected in this regard. However, given the high potential of damage caused by these weevils in their invasive ranges, understanding their identity, distribution and trophic relationships is essential to better inform their management (Barratt et al ., 2018) and to prepare specific biosecurity regulations (Health et al ., 2018). In this study, we explore the species composition, phenology and trophic relationships of Gonipterus in a non‐commercial eucalypt plantation in South East Queensland, to provide an insight into the ecology of the genus in subtropical Australia.…”

The application of rapid evaporative ionization mass spectrometry in the analysis of Drosophila species—a potential new tool in entomology

“…Biosecurity, which aims at curtailing risk through 'biological harm' [12], relies largely on rapid and accurate species identification as it affects risk assessments, the handling of imported goods and plans for future surveillance or eradication [13,14]. Correct identification likewise influences biological pest control strategies, such as the use of insect pheromones or prey/predator interactions, as their success is based on species-specific mechanisms [15][16][17][18]. In countries and regions where insects are a public health concern (for example, mosquitoes), specimens are routinely trapped for identification and other analytical purposes.…”

Soil macro-fauna respond to environmental variations along a coastal-inland gradient

“…Formicidae is considered to be a type of omnivore, with such nutritional sources as leaves, seeds, small insects and nectar. The majority of the Curculionidae feed exclusively on plants, including seeds, stems, flower heads and roots (Barratt, Cock & Oberprieler, 2018). The Aphodiidae is mainly detritivore, feeding on plant residue or dung produced by various animals (Finch et al, 2020;Buse et al, 2018).…”