Canadian Forest Service Publications
Identification and genetic diversity of two invasive Pissodes spp. Germar (Coleoptera: Curculionidae) in their introduced range in the southern hemisphere. 2016. Wondafrash, M; Slippers, B.; Garnas, J.; Roux, G.; Foit, J.; Langor, D.W.; Hurley, B.P. Biological Invasions 18(8):2283-2297.
Issued by: Northern Forestry Centre
Catalog ID: 37396
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During the first half of the twentieth century, two accidental cases of introduction of Pissodes weevils were recorded from the southern hemisphere. The weevils in South Africa were identified as the deodar weevil (Pissodes nemorensis) and those in South America as the small banded pine weevil (Pissodes castaneus). Wide distribution of the two species in their invasive range, general difficulty in identifying some Pissodes spp., and the varying feeding and breeding behaviours of the species in South Africa has necessitated better evidence of species identity and genetic diversity of both species and population structure of the species in South Africa. Barcoding and the Jerry-to-Pat region of the COI gene were investigated. Morphometric data of the South African species was analysed. Our results confirmed the introduction of only one Pissodes species of North American origin to South Africa. However, this species is not P. nemorensis, but an unrecognized species of the P. strobi complex or a hybrid between P. strobi and P. nemorensis. Only P. castaneus, of European origin, was identified from South America. We identified ten mitochondrial DNA haplotypes from South Africa with evidence of moderate genetic structure among geographic populations. Terminal leader and bole-feeding weevils did not differ at the COI locus. A single haplotype was identified from populations of P. castaneus in South America. Results of the present study will have implications on quarantine, research and management of these insect species.
Plain Language Summary
It is important to accurately identify invasive insect pests and their genetic diversity to develop successful programs to manage these pests. Weevils pose a threat to coniferous trees by feeding on them and transmitting fungal diseases. While all species in the Pissodes genus are from the northern hemisphere, one species has been accidentally introduced to South Africa and another to South America. This study looked at these introduced species to accurately identify them and to determine their genetic diversity and aspects of their populations such as geographic distribution as well as feeding and breeding behaviours. It found that the weevil in South African had been misidentified in 1942 and is actually a different species, but one that is not now known, either an unknown member of a North American group of weevils or a hybrid between this group and the species originally identified incorrectly. It is, however, clear that it came from North America. The species in South America was confirmed as the small banded pine weevil, and genetic analysis shows that these weevils in Chile, Argentina and Uruguay come from a single, fairly recent introduction.