Review and key to Nearctic Lathrolestes Förster (Hymenoptera: Ichneumonidae), with special reference to species attacking leaf mining tenthredinid sawflies in Betula Linnaeus (Betulaceae)

All Holarctic members of the genus Lathrolestes Förster (Hymenoptera: Ichneumonidae) were reviewed. Five species are described as new: L. syringe Reshchikov sp. nov., L. barroni Reshchikov sp. nov., L. fissus Reshchikov sp. nov., L. thomsoni Reshchikov sp. nov., and L. soperi Reshchikov sp. nov. The last two species were reared from Profenusa thomsoni (Konow, 1886), an invasive European birch leafmining sawfly found in North America. Lathrolestes nasoni Davis, 1897 is synonymized with L. caudatus (Thomson, 1883); L. scutellatus (Ashmead, 1890) stat. rev. is reestablished as a valid species.

Current status of invasive alien birch-leafmining sawflies (Hymenoptera: Tenthredinidae) in Canada, with keys to species

In the 20th century, five species of birch-leafmining sawflies were inadvertently introduced from Europe to North America: Heterarthrus nemoratus (Fallén), Fenusa pumila Leach, Profenusa thomsoni (Konow), Fenusella nana (Klug), and Scolioneura vicina Konow. All have been recorded at outbreak levels in North America, and three (F. pumila, P. thomsoni, and H. nemoratus) have been the targets of successful biological control programs. The most recently detected species, F. nana and S. vicina, are good candidates for future biological control in Canada. We review the biology of all five of these birch-leafmining sawflies in North America and present keys to adults, larvae, and mines to aid correct identification.

Mitochondrial DNA variation in two invasive birch leaf-mining sawflies in North America

Mitochondrial cytochrome oxidase I and II genes were sequenced for two invasive alien birch (Betula L. [Betulaceae]) leaf-mining sawflies, Profenusa thomsoni (Konow, 1886) (Hymenoptera: Tenthredinidae) and Scolioneura betuleti (Klug, 1816) (Hymenoptera: Tenthredinidae), accidentally introduced from Europe to North America. Ten North American and two European populations of P. thomsoni were sampled. As no genetic variation was observed for this parthenogenic species in Europe or North America, there is no evidence that this species was introduced more than once into North America. A single Canadian population of putative S. betuleti was genetically characterized and compared with populations of S. betuleti and Scolioneura vicina Konow, 1894 in Europe to resolve the species identity of the introduced Canadian population. Three haplotypes were present in European material but only one haplotype was represented in material collected in Canada. The haplotype in the Canadian population occurred in both S. betuleti and S. vicina in Europe. Thus, this preliminary genetic work cannot provide certain identity of the Canadian species. Moreover, there was no significant genetic difference between putative S. betuleti and S. vicina in Europe, leading us to suggest that S. vicina may not be reproductively isolated from S. betuleti, despite ecological differences.

Distributions of leafmining sawflies (Hymenoptera: Tenthredinidae) on birch and alder in northwestern Canada

Exotic leafmining sawflies (Hymenoptera: Tenthredinidae) on birch (Betula spp., Betulaceae) have become widely distributed in Canada since their introduction to eastern North America in the last century (Digweed et al. 1997). However, their distributions north of the 60th parallel are poorly known (Digweed et al. 2003). No birch leafmining sawflies were detected at Hay River and Louise Falls, Northwest Territories (NT), in 1993, but the ambermarked birch leafminer, Profenusa thomsoni (Konow), was reported from Yellowknife, NT, in 1994 (Digweed et al. 1997). Since that time, P. thomsoni populations have reached epidemic levels on urban birches in Yellowknife and Hay River, NT (unpublished data). While examining infested birches in Hay River in 2003, the authors also found the European alder leafminer, Fenusa dohrnii (Tischbein), attacking alder (Alnus spp., Betulaceae).