Tracing the origin of a cryptic invader: phylogeography of theEuwallacea fornicatus(Coleoptera:Curculionidae:Scolytinae) species complex

Abstract

1 The ambrosia beetle morphologically identified as Euwallacea fornicatus consists of several cryptic species that exhibit large differences in the DNA sequences of several nuclear and mitochondrial gene regions. 2 Based on these differences, we suggest that there are at least three different species each with distinct phylogeography. 3 Members of this cryptic species complex have invaded many areas outside their native range and cause substantial damage to both agriculture (avocado in particular) and other tree species. 4 Three of these cryptic species have invaded the USA: two species in California and a third species in both Florida and Hawaii. 5 Identification of their native range allows directed search for their natural enemies that may be used in biological control of these tree pests.

Dispersal behaviour of Euwallacea nr. fornicatus (Coleoptera: Curculionidae: Scolytinae) in avocado groves and estimation of lure sampling range

“…A third population, discovered in Florida in 2002 (CABI, 2017), is now proposed to be an introduction of the original tea shot‐hole borer (Stouthamer et al ., ) (for consistency with previously published reports, the name Euwallacea nr. fornicatus is be retained here).…”

“…Two genetically distinct populations (comprising species yet to be described) are now established in California, referred to as polyphagous shot‐hole borer and Kuroshio shot‐hole borer, and each vectors a unique assemblage of symbionts (Eskalen et al ., , ; Kasson et al ., ; O'Donnell et al ., ; Boland, ; Stouthamer et al ., ). Both beetles are significant pests of urban and wetland forests, colonizing and killing apparently healthy trees, especially boxelder Acer negundo L. (Aceraceae) and willow Salix spp.…”

Temperature can limit the invasion range of the ambrosia beetle Euwallacea nr. fornicatus

“…The polyphagous shot hole borer (PSHB) Euwallacea nr. fornicatus (Coleoptera: Curculionidae; Scolytinae) is an ambrosia beetle native to Southeast Asia (Stouthamer et al ., ) that has invaded southern California (Eskalen et al ., ), Israel (Mendel et al ., ) and South Africa (Paap et al ., ). As an ambrosia beetle, PSHB has formed a symbiotic relationship with the fungi Fusarium euwallaceae , Graphium euwallaceae and Paracremonium pembeum , which are transported within special invaginations referred to as mycangia (Lynch et al ., 2016).…”

Description of two new species closely related to Doryctobracon areolatus (Szépligeti, 1911) (Hymenoptera, Braconidae), based on morphometric and molecular analyses

“…ITS regions accumulate variability that allows the successful differentiation of species or strains of the same species (Silva et al 1999;Ciociola Jr. et al 2001;Gallego & Gálian 2001;Müller et al 2007). The D2-D3 regions of the 28S ribosomal gene provide an alternative method for phylogenetic analysis, which can equally be used to test and supplement hypotheses derived from morphological analyses (Taylor et al 2006;Stouthamer et al 2017).…”