Tomicus piniperda and T. destruens are sibling species which are extremely difficult to separate by morphological characters. Although several papers report differences between the two species, many characters need confirmation or better description. Moreover, new morphological characters are required for correct species determination. For these purposes, eight populations of T. destruens from Italy, Greece, Spain and Algeria, and ten of T. piniperda from Finland, Poland, Czech Republic, Austria, Sweden and Italy, were investigated considering eleven morphological characters. The morphological differences most useful for the species separation include four previously described characters (colour of the elytra, colour of the antennal club, distribution of the antennal setae, distribution of the punctures along the elytral declivity), and four new characters (body proportions, setation of the first antennal club suture, sculpture of the elytral declivity and striae density of the pars stridens). Distribution of the two species is discussed and an illustrated key is included.
Tomicus piniperda is a pest in pine stands in Eurasia and is also found in the USA, where it has caused a decline in the abundance of pine since 1992. Knowledge of the genetic structure of pine shoot beetle populations is important for understanding their phylogeographic history and for quarantine control. In this study, European, Asian and American T. piniperda populations were analyzed by sequencing a region of the mitochondrial COI gene. Twenty-five haplotypes (HT) were detected and over 70% of these HT were found in individual areas, e.g. 5 HT in China, 5 HT in France and 3 HT in Spain. Nested clade analysis revealed that most European and the American population was in a clade containing 9 HT connected by one to two mutational steps. A second clade contained HT from France (2 HT), Spain (2 HT), Sweden (1 HT), Russia (1 HT) and China (5 HT). In this clade, one to 13 mutational steps and 13 missing or theoretical HT were detected. The third clade had 5 HT from France, Russia, Poland, Finland and Switzerland; 1 to 7 mutational steps and 5 missing or theoretical HT were detected. Although only a few significant relationships were found in the nested clade analysis, the following conclusions can be drawn: (1) T. piniperda is a polymorphic species with numerous HT throughout Europe, and HT are likely to exist regarding the missing or theoretical HT; (2) It is likely there were refugial areas in Southern Europe and Western Russia; (3) The Pyrenees formed a barrier to migration after the last ice age; (4) Chinese and European populations have been separated for at least 0.6 MYA.