Morphological and genetic identification of the three pine pests of the genus Tomicus (Coleoptera, Scolytidae) in Europe

Abstract

1 Morphological characters were elaborated and part of the mitochondrial COI gene was sequenced in order to facilitate the determination of the three European pine bark beetles Tomicus piniperda, T. destruens and T. minor. The sequence information also provided the first information on the phylogenetic and phylogeographical relationships of these species. 2 Three hair rows were found on the antennal club of T. destruens between the second and third suture. Tomicus piniperda had only one row. Three different hair types were detected on the elytra ± two hair types were found on T. piniperda, whereas the third hair type was only detected on the elytra of T. destruens. 3 The COI region (445 bp) revealed high sequence divergence among T. destruens, T. piniperda and T. minor. The three species proved to be monophyletic species with 16.98±19.23% sequence divergence. A phylogenetic approach placed T. minor and T. destruens as sister taxa, which contradicts the morphological findings. 4 European populations of T. piniperda shared two haplotypes, indicating a homogenous distribution of the genotypes. In the American populations only one of these European haplotypes was found. The Greek, Italian and Spanish T. destruens populations revealed three population-specific haplotypes, indicating restricted gene flow. 5 Species-specific primers were designed to allow a rapid and definitive determination of the two sibling Tomicus species by PCR.

Genetic structure and phylogeography of pine shoot beetle populations (Tomicus destruens and T. piniperda, Coleoptera Scolytidae) in Italy

“…However, it was possible to verify that some Italian haplotypes were already found in Europe. In particular, the haplotypes B and F were the most common haplotypes found in all the investigated Italian populations, as well as in many French and Spanish populations [11,15,16], suggesting their older origin. Besides, the haplotype G found in insects sampled from Pinus halepensis (ITA4), was found also in France from the same host tree [15], indicating a possible differentiation in relation to this host or its habitat, which is typical of warm and dry Mediterranean areas.…”

“…2b). The haplotype A was the only found in four specimens of a Greek population [16], suggesting a Balkan origin of the ITA1 population. In fact, this population originates from a coastal plantation of Mediterranean pines about 50 years old, belonging to a system of plantations created to protect the Adriatic coasts since the Roman time, about 2000 years ago [8].…”

“…A fragment of about 490 bp of the Cytochrome Oxidase I (COI) was amplified using the lepidopteran mitochondrial primers C1J2441 [29] for both the Tomicus species, and C1N2934, and C1N2937 for T. destruens and T. piniperda, respectively [16]. Once sequenced, the COI fragments were used to design a Tomicus specific primer TMC2 (5'-ATTGATGAAATAATATTTCATATAAAATATGC-3').…”

“…However, recent papers reported both morphological and genetic characters useful for the separation of the two siblings [11,15,16]. Nevertheless, species determination by morphological analysis is still extremely difficult, and the genetic support is needed.…”

Sydowia polyspora Dominates Fungal Communities Carried by Two Tomicus Species in Pine Plantations Threatened by Fusarium circinatum

“…Therefore, molecular identification by PCR was carried out with extracted DNA from all the collected insects according to Vainio et al [23]. The selected method for species identification was the one described by Kohlmayr et al [24] based on amplification of cytochrome oxidase I gene (COI) using specific primer pairs. Briefly, the primer pair C1-J-2441 (5 -CCTACAGGAATTAAAATTTTTAGATGATTAGC-3 ) [25] and C1-N-2937 (5 -ATATTGGAATCACTCAATTGAG-3 ) was used to identify T. piniperda samples.…”