Vol 99, No 5 (2019)

This paper presents the results of analysis of the taxonomic diversity, distribution, and host associations of the flea species recorded so far as the plague microbe vectors. The ecological features and epizootic significance of the flea Citellophilus tesquorum (Wagner, 1898), a parasite of ground squirrels, are specially considered.

Nematode pathogens cause wilt diseases in conifers and deciduous trees. The longhorn beetles (Coleoptera: Cerambycidae) and bark beetles (Coleoptera: Curculionidae: Scolytinae) act as nematode vectors spreading the invasive juvenile stages during their maturation feeding or during oviposition on the plant hosts. There are numerous reviews of nematodes associated with bark beetles on conifers, while little attention has been paid to the nematodes of deciduous trees. The development of Dutch elm disease and ash dieback is mainly caused by fungal pathogens transmitted by bark beetles; the latter act as vectors of not only fungi but also nematodes enclosed in nematangia under their elytra, and also in the tracheae and Malpighian canals. Apart from phytopathogenic nematodes, bark beetles transmit mycophagous and bacterivorous nematodes and own parasites of bark beetles. The ecological groups of nematodes associated with Scolytinae are reviewed; the known records of associations of nematodes with bark beetles are listed for coniferous host plants of Russia and neighboring countries; the world-wide list of these associations for deciduous plant hosts is given.

Geographic variability of the thoracic chaetome in females of Coquillettidia richiardii (Ficalbi, 1889) and Culex modestus Ficalbi, 1890 was revealed for the first time. We found statistically significant differences in the number of setae between populations from various regions. In particular, Coquillettidia richiardii females from Romania and Moldova have on average a greater number of postpronotal and prealar setae as compared with conspecific females from St. Petersburg and Leningrad Province of Russia. Culex modestus females from Uzbekistan, Kyrgyzstan, and Leningrad Province have on average fewer postpronotal, prealar, mesepisternal, and upper mesepimeral setae than the females from Rostov Province of Russia.

The small spruce bark beetle Ips amitinus is a widespread species in many European countries that has been actively spreading into Northern Europe in the recent decades. In Russia, I. amitinus is present in the western, northwestern, and northern regions of the European part, with a tendency for range expansion. The species was first recognized in West Siberia in 2019 by characteristic morphological features and molecular genetic analysis. This bark beetle is abundant on Pinus sibirica in Siberian pine forests located near settlements within Tomsk and Kemerovo provinces, and is also sporadically found on the Siberian spruce Picea obovata. It colonizes the upper trunk and branches of standing and windfall trees. In the outbreak foci this bark beetle causes catastrophic drying of Siberian pines, starting from the crown top. This pattern of tree drying was noted for the first time near settlements in Yashkinsky District of Kemerovo Province in 2014, and now outbreak foci of I. amitinus exist in all the Siberian pine forests in this district. The population growth of I. amitinus was probably facilitated by dry and hot summer weather in the southeast of West Siberia during the last decade, in 2011 and 2012, and also by heavy winter snowfalls leaving numerous snapped tree branches which are easily colonized by the pest. In Tomsk Province, the most active outbreak focus of I. amitinus appeared in 2018 in the Siberian pine forest near Luchanovo and Ipatovo, following an outbreak of the Siberian moth Dendrolimus sibiricus. The invasion of I. amitinus in Siberia may increase the degradation rates not only of the gene-reserve Siberian pine forests but also of other dark coniferous stands.

The net-wing beetle Lopheros lineatus (Gorham, 1883), previously known in the western Palaearctic only from Poland, and in the eastern Palaearctic, from the southern Russian Far East and from Japan, is discovered in Mordovia, Central Russia.