Distribution and Trophic Associations of Herbivorous Bark Beetles of the Genus Thamnurgus Eichhoff (Coleoptera,Curculionidae: Scolytinae) in the Volga Region and in the Urals

Entomological Review - Based on the author’s and literature data, three species of the scolytid genus Thamnurgus Eichhoff, 1864 associated with herbaceous plants are reported from the Volga...     

Bark and Ambrosia Beetles (Coleoptera,Curculionidae: Scolytinae) of Northwest Russia: History of the Study,Composition and Genesis of the Fauna

Entomological Review - An essay of the fauna of bark beetles (Coleoptera: Curculionidae: Scolytinae) in five federal subjects of Northwest Russia is presented. The species composition of scolytids...     

Taxonomic changes in palaeotropical Xyleborini (Coleoptera, Curculionidae, Scolytinae)

Following the recent reclassification of the Palaeotropic xyleborine genera (Hulcr and Cognato in press), additional species are transferred to correct genera or synonymized based on analysis of their morphological characters. The following species are given new combinations: Debus amphicranoides (Hagedorn), comb. n., Debus birmanus (Eggers, 1930), comb. n., Debus dolosus (Blandford, 1896), comb. n., Debus eximius (Schedl, 1970), comb. n., Debus interponens (Schedl, 1954), comb. n., Debus robustipennis (Schedl, 1954), comb. n., Debus spinatus (Eggers, 1923), comb. n., Microperus alpha (Beeson, 1929), comb. n., Microperus corporaali (Eggers), comb. n., Microperus eucalyptica (Schedl, 1938), comb. n., Microperus nugax (Schedl, 1939), comb. n., Pseudowebbia percorthylus (Schedl, 1935), comb. n., Truncaudum circumcinctus (Schedl, 1941), comb. n.THE FOLLOWING SPECIES ARE SYNONYMIZED: Arixyleborus hirtipennis (Eggers), syn. n., with Arixyleborus puberulus (Blandford); Coptoborus palmeri (Hopkins), syn. n., with Debus emarginatus (Eichhoff); Coptoborus terminaliae (Hopkins), syn. n., with Debus emarginatus (Eichhoff); Cyclorhipidion polyodon (Eggers), syn. n., with Truncaudum agnatum (Eggers); Euwallacea artelaevis (Schedl), syn. n., with Planiculus bicolor (Blandford); Xyleborinus perminutissimus (Schedl), syn. n., with Xyleborinus perpusillus (Eggers); Xyleborus exesus Blandford, syn. n., with Debus emarginatus (Eichhoff); Xyleborus fulvulus (Schedl), syn. n., with Microperus corporaali (Eggers); Xyleborus marginicollis (Schedl), syn. n., with Diuncus justus (Schedl); Xyleborus shoreae Stebbing, syn. n., with Debus fallax (Eichhoff).THE FOLLOWING SPECIES ARE GIVEN NEW STATUS: Streptocranus superbus (Schedl, 1951), restored name; Webbia divisus Browne, 1972, restored name; Webbia penicillatus (Hagedorn, 1910), restored name. Genus Taphrodasus Wood (1980) is declared not valid.     

Small Spruce Bark Beetle Ips amitinus (Eichhoff, 1872) (Coleoptera,Curculionidae: Scolytinae): a New Alien Species in West Siberia

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.

     

First Record of the Four-Eyed Fir Bark Beetle Polygraphus proximus Blandford, 1894 (Coleoptera,Curculionidae: Scolytinae) from Irkutsk Province,Russia

Entomological Review - Polygraphus proximus Blandford, 1894 is recorded for the first time for Irkutsk Province of Russia. The species was collected in the vicinity of Utulik Village in Slyudyansky...     

The Polyphagous Bark Beetle Hypothenemus eruditus (Westwood, 1836) (Coleoptera,Curculionidae, Scolytinae): the First Record on Buxus Trees in Russia

Entomological Review - The formation of Hypothenemus eruditus foci is described on a tree of Buxus sempervirens ssp. colchica which died as the result of damage caused by larvae of Neoglyphodes...     

Bark beetles and pinhole borers (Curculionidae, Scolytinae, Platypodinae) alien to Europe

Invasive bark beetles are posing a major threat to forest resources around the world. DAISIE's web-based and printed databases of invasive species in Europe provide an incomplete and misleading picture of the alien scolytines and platypodines. We present a review of the alien bark beetle fauna of Europe based on primary literature through 2009. We find that there are 18 Scolytinae and one Platypodinae species apparently established in Europe, from 14 different genera. Seventeen species are naturalized. We argue that Trypodendron laeve, commonly considered alien in Europe, is a native species; conversely, we hypothesize that Xyleborus pfeilii, which has always been treated as indigenous, is an alien species from Asia. We also point out the possibility that the Asian larch bark beetle Ips subelongatus is established in European Russia. We show that there has been a marked acceleration in the rate of new introductions to Europe, as is also happening in North America: seven alien species were first recorded in the last decade.We present information on the biology, origins, and distributions of the alien species. All but four are polyphagous, and 11 are inbreeders: two traits which increase invasiveness. Eleven species are native to Asia, six to the Americas, and one is from the Canary Islands. The Mediterranean is especially favorable for invasives, hosting a large proportion of the aliens (9/19). Italy, France and Spain have the largest numbers of alien species (14, 10 and 7, respectively). We point out that the low numbers for at least some countries is likely due to under-reporting.Finally, we discuss the difficulties associated with identifying newly invasive species. Lack of good illustrations and keys hinder identification, particularly for species coming from Asia and Oceania.     

Susceptibility of Sap Beetles (Coleoptera: Nitidulidae) to Entomopathogenic Nematodes

Nitidulid beetles (Coleoptera) are considered to be serious pests of date palms throughout the world. They attack ripe fruit, causing it to rot, and damage is reflected in both reduced yield and lower fruit quality. The present study was aimed at an evaluation of the susceptibility to different sap beetles to entomopathogenic nematodes. We further tested nematode efficacy in pots filled with soil infested by third instar larvae of the two beetle species. In Petri dish assay, mortality levels of Carpophilus humeralis and C. hemipterus exposed to Heterorhabditis sp. IS-5 strain indicated that the latter is less susceptible to nematode infection. Exposure of both sap beetle species to different nematode strains gave moderate levels of mortality (35-65%) with the heterorhabditid strains HP88, IS-5 and IS-25. The IS-12 strain of Heterorhabditis sp. showed poor virulence (<35% mortality) against larvae of C. humeralis as well as larvae and pupae of C. humipterus. The nematode species S. riobrave showed moderate virulence (35-65%) mortality to larvae and pupae of S. humeralis as well as to larvae of C. hemipterus . Exposure of C. hemeralis to different concentrations of Heterorhabditis sp. IS-5 in pots containing soil resulted in high mortality (>65%). In contrast, the lower concentrations (500 and 1000 nematodes/pot) caused low mortality (35%) of C. hemipterus . Other heterorhabditid strains caused 95-100% mortality of C. humeralis in pot assay. The HP88 strain of H. bacteriophora and the Tx strain of Steinernema riobrave showed poor effectiveness. Incubation of different nematode strains with the C. humeralis larvae at high temperature (32 C) resulted in an increase in insect mortality with the IS-12 and IS-21 strains. Reduced mortality was recorded with the HP88 strain treatment at the higher temperature. The IS-5 and IS-12 strains were equally effective in all three soil types tested, whereas the IS-19 strain was more effective in the Almog type soil than in the others.     

Phylogeography of the bark beetle Dendroctonus mexicanus Hopkins (Coleoptera: Curculionidae: Scolytinae)

Dendroctonus mexicanus is polyphagous within the Pinus genus and has a wide geographical distribution in Mexico and Guatemala. We examined the pattern of genetic variation across the range of this species to explore its demographic history and its phylogeographic pattern. Analysis of the mtDNA sequences of 173 individuals from 25 Mexican populations allowed to us identify 53 geographically structured haplotypes. High haplotype and low nucleotide diversities and Tajima’s D indicate that D. mexicanus experienced rapid population expansion during its dispersal across mountain systems within its current range. The nested clade phylogeographic analysis indicates that the phylogeographic pattern of D. mexicanus is explained by continuous dispersion among lineages from the Sierra Madre Occidental, the Sierra Madre Oriental and the Trans-Mexican Volcanic Belt. However, we also observed isolation events among haplotypes from the Cofre de Perote/Trans-Mexican Volcanic Belt/Sierra Madre Oriental and the Trans-Mexican Volcanic Belt/Sierra Madre del Sur, which is consistent with the present conformation of mountain systems in Mexico and the emergence of geographical barriers during the Pleistocene.     

Alimentary canal and reproductive tract of Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae, Scolytinae)

The alimentary canal and the reproductive tract of males and females of Hypothenemus hampei Ferrari are described. The alimentary canal of H. hampei showed the crop with several spine-like structures and the midgut with few gastric caeca. We evidenced for the first time that adult females need to feed on coffee in order to produce viable eggs before and during oviposition period. The presence of air bubbles inside the anterior midgut may be due to starvation rather than the response of the environment during flying as previously reported. Two ovaries and the same structures and arrangements common to individuals of the Curculionidae beetles composed the female reproductive system. The male reproductive tract showed a significant difference with respect to other Curculionidae and even other Scolytinae species as it showed a sclerotized aedeagus with several pore-like structures in the terminal portion where sperm is released during mating.     

Mating Behavior of the Coffee Berry Borer, Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae: Scolytinae)

The mating behavior of the coffee berry borer, Hypothenemus hampei (Ferrari), was observed under laboratory conditions. Pairs of adult virgin male and female beetles were placed in the wells of a polystyrene microtiter plate, one pair per well. The mating activity of each pair was recorded for 24?h. The mating behavior of the coffee berry borer was similar to that of other Scolytinae and was clearly divided into precopulatory, copulatory and postcopulatory phases. The beetles started to mate within a few hours of emergence. Repeated mating occurred during the 24-hour period and increased in frequency with age. However, we cannot address multiple matings in H. hampei, since we did not simulate the female-biased sex ratio of this species and the experimental design did not allow females to avoid additional mating attempts by males. In addition, further studies are necessary that focus on the effectiveness of sperm transmission and direct and indirect effects of multiple matings on the H. hampei females and their offspring.     

Five new species of Triotemnus (Coleoptera, Curculionidae, Scolytinae) from Morocco and Yemen

Fivenew species of the genus Triotemnus from Morocco and Yemen are described. Triotemnus is a new genus of Scolytinae for the Yemen region. External morphology of the new species and all morphologically related species of the genus were studied. While the new species from Morocco are morphologically similar to the known species from the corresponding region, all three newly described species from Yemen, mainly two of them living in Socotra, are morphologically very different from all other known species of the genus. Geographical distribution and the probability of endemicity are discussed.     

A New Genus and Species of Scolytinae (Coleoptera: Curculionidae) from the Rovno Amber

A new genus, Klesovia gen. nov., with the species K. pubescens sp. nov. (Coleoptera: Curculionidae) are described from the Rovno amber. The new genus is closely related to Xylechinus (tribe Hylurgini) and distinguished by the wide flattened ovoid antennal club with rounded apex and the metepisternum covered with long thin sparse setae; it differs from other genera of Hylurgini in having a five-segmented funicle, four-segmented club, and large distance between the procoxa.     

New ichnotaxon Megascolytinus zherikhini (Coleoptera: Curculionidae: Scolytinae) from upper cretaceous deposits of mongolia

Gallery systems of Scolytinae on a petrified Araucaria trunk fragment from the Late Cretaceous of Gobi, Mongolia, similar to those of extant members of the supertribe Hylesininae, but exceptionally large (estimated body length of the beetle about 20 mm), are described as a new ichnotaxon, Megascolytinus zheriknini.     

New species and records of Cactopinus Schwarz with a key to species (Coleoptera, Curculionidae, Scolytinae)

Three new species in the genus Cactopinus Schwarz are described from Mexico and the U.S., bringing the total of known species to 21. New host and distribution records and a new key to species are included.     

Additions to the check list of bark beetles (Coleoptera,Curculionidae: Scolytinae) from Leningrad Province,Russia

The field work of the authors during the last 16 years in both the western and the eastern parts of Leningrad Province, Russia, has resulted in the addition of 7 species to the regional list of bark beetles, namely: Hylurgus ligniperda F., Crypturgus subcribrosus Egg., Pityogenes irkutensis Egg., Scolytus mali Bechst., S. scolytus F., S. pygmaeus F., and Xyleborinus attenuatus Blandf. Of these species, P. irkutensis occurs only in the eastern districts of Leningrad Province, C. subcribrosus, over the whole territory, and the remaining species, only in the western districts. We suggest excluding Polygraphus proximus Blandf. from the regional faunal list. As a result, the updated list of the bark beetle species of Leningrad Province comprises 75 taxa. New data on findings of rare species in the region are considered.     

Optimizing ethanol-baited traps for monitoring damaging ambrosia beetles (Coleoptera: Curculionidae, Scolytinae) in ornamental nurseries

The exotic ambrosia beetles Xylosandrus crassiusculus (Motschulsky) and Xylosandrus germanus (Blandford) (Coleoptera: Curculionidae: Scolytinae) are serious pests in ornamental tree nurseries. To optimize bottle-traps as a monitoring system for X. crassiusculus and X. germanus in nurseries, we tested whether increasing the rate of commercial ethanol lures improved captures or early detection of these species. Experiments were conducted in Ohio (2008 and 2009) and Virginia (2008), two states that have experienced significant damage from X. crassiusculus, X. germanus, or both. There were four treatments: no-lure (unbaited control), 1-ethanol lure, 2-ethanol lures and 1 + 1-ethanol lures (one lure in the trap and one suspended 0.5 m above the trap). Captures of X. crassiusculus and X. germanus were higher in all ethanol treatments than unbaited controls, and were generally higher in treatments with two lures versus one. There was no difference in beetle captures between the 2-lure and 1 + 1-lure treatments. First detection of X. crassiusculus and X. germanus occurred more consistently in the treatments with two lures than one lure. Xyleborinus saxesenii (Ratzeburg), Anisandrus sayi Hopkins, Hypothenemus dissimilis Zimmermann, and Hypothenemus eruditus Westwood were also more attracted to traps baited with ethanol than unbaited controls. X. saxesenii was captured in higher numbers in the treatments with two lures than one in Virginia but not in Ohio. There was no difference in captures of the other species among ethanol treatments. The current research shows that ethanol release rates influence sensitivity of traps for detecting emergence of overwintered ambrosia beetles.     

Polyphyly of Xylosandrus Reitter inferred from nuclear and mitochondrial genes (Coleoptera: Curculionidae: Scolytinae)

The Xyleborina ambrosia beetle genus Xylosandrus contains 54 species, several of which are of economic importance. The monophyly of the genus was tested using a data set comprised of multiple gene loci: 28S rDNA; the mitochondrial gene cytochrome oxidase I (COI); and the nuclear genes arginine kinase (ArgK), rudimentary (CAD), and Elongation Factor 1α (EF-1α). The nuclear protein-coding genes CAD and ArgK were used for the first time in phylogenetics of Scolytinae. Analyses were performed using Parsimony and Bayesian optimality criteria. Our analyses included 43 specimens representing 15 Xylosandrus species and 20 species from Amasa, Anisandrus, Cnestus, Euwallacea and Xyleborus, and two species from the outgroup genus Coccotrypes. All analyses recovered a polyphyletic Xylosandrus. Several species of Xylosandrus were consistently placed in clades with the genera Anisandrus and Cnestus with high support values (100% bootstrap support). Among these, was the economically important invasive species X. mutilatus, which was consistently recovered as part of the “Cnestus” clade. In our analyses, both CAD and ArgK demonstrated phylogenetic utility across varying nodal depths. Despite the selection of genes with signals at complementary phylogenetic depths, the data set used herein did not resolve the phylogeny of Xylosandrus and related genera. Since the taxon sample available for molecular work represents only a fraction of Xylosandrus species, a complete revision that combines molecular and morphological data in a total evidence approach is recommended for the genus.