A new genus and species of the rove beetle tribe Mesoporini from Baltic amber (Coleoptera: Staphylinidae: Aleocharinae)

A new extinct rove beetle, Palaeomesoporus electiricus gen. et sp.n., is described from a single specimen of Eocene Baltic amber. This fossil beetle is placed in the tribe Mesoporini, a ‘basal’ group of the mega-diverse subfamily Aleocharinae. Palaeomesoporus is easily discriminated from other mesoporine genera due to its less-developed antennal club, longer and slender elytron lacking a sinuate posterior margin, and prominently shorter mesotarsus. This finding sheds light on the paleodiversity and evolutionary history of the tribe and ‘basal’ Aleocharinae.     

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.     

A new genus and species of timber beetle (Coleoptera: Lymexylidae) from the Baltic amber

Ponomarenkylon alexandri gen. et sp. nov. (Melittommatinae) from the Late Eocene Baltic amber is described. The long filiform antennae and the apparent absence of sensillary organs, which are frequently present on modified maxillary palps in other lymexylids, are evidence of the primitive state of the new genus.     

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.     

Gut-associated yeast in bark beetles of the genus Dendroctonus Erichson (Coleoptera: Curculionidae: Scolytinae)

Scolytine bark beetles are the most destructive pests of conifers; they sometimes aggregate in such large numbers that they actually kill their hosts. They maintain close relationships with yeasts and fungi, in particular those that are assumed to aid in digestive, detoxification processes and pheromone production. In this study, 403 yeast strains were isolated from the guts, ovaries, eggs and frass of nine bark beetle species in the genus Dendroctonus Erichson. The beetles were collected from 10 conifer species at 34 locations in Mexico, Guatemala and the USA. Yeast identification was based on partial DNA sequences from 18S rDNA, 26S rDNA and internal transcribed spacer (ITS1), as well as morphological and physiological characteristics. A combined phylogenetic analysis delimited 11 clades with sequences similar to Candida arabinofermentans , C. ernobii , C. membranifaciens (including C. lessepsii , Pichia mexicana and P. scolyti ), C. oregonensis , C. piceae , Kuraishia capsulata (including K. capsulata and K. cf. molischiana ), Pichia americana , P. canadensis , P. glucozyma , P. guilliermondii and an undescribed species of Candida . Nucleotide divergences between the major clades were at least 5% while, with the exception of 30 isolates, yeasts within clades differed from named reference species at fewer than 1% of the nucleotide sites. There do not appear to be obligate relationships between particular yeasts and specific anatomical partitions, nor between particular yeasts and bark beetle species. Some yeasts do appear to be preferentially associated with bark beetles feeding on different conifer genera and therefore host plant defences may limit yeast community diversity in Dendroctonus .  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 98 , 325–342.     

Number of gallery arms of the tree-killing bark beetle Polygraphus proximus (Coleoptera: Curculionidae: Scolytinae)

Polygraphus proximus Blandford (Coleoptera: Curculionidae: Scolytinae) is a non-aggressive monogynous bark beetle that has caused mass mortality in fir (Abies spp.) forests in the last decade. Although gallery structures made by polygynous beetles may influence their reproductive success, the gallery structure and the number of eggs laid by the monogynous tree-killing bark beetle P. proximus has not been investigated in detail in the natural setting of their native range. We, therefore, investigated the length of mother galleries of P. proximus and the number of eggs oviposited by the beetles in relation to gallery systems with different numbers of arms. The number of eggs oviposited in two-armed galleries was significantly greater than that observed in one- and three-armed galleries. Additionally, the length of one- or two-armed galleries with no oviposition was significantly shorter than that in galleries consisting of more than two arms. Our data may suggest that the optimal number of arms in a gallery system (in terms of the number of eggs oviposited) was two.     

Fitness consequences of pheromone production and host selection strategies in a tree-killing bark beetle (Coleoptera: Curculionidae: Scolytinae)

Timing of arrival at a resource often determines an individual’s reproductive success. Tree-killing bark beetles can reproduce in healthy trees by attacking in adequate numbers to overcome host defences that could otherwise be lethal. This process is mediated by aggregation and antiaggregation pheromones. Beetles that arrive early in such a “mass attack” must contend with undiminished tree defences, and produce enough pheromones to attract more beetles, but have a head start on gallery construction and egg-laying. Beetles that arrive late may be impeded by competition and diminishing availability of phloem, but should experience fewer costs associated with pheromone production and battling tree defences. We investigated relationships between timing of arrival, body size, pheromone production and fitness in the southern pine beetle, Dendroctonus frontalis. In field experiments, we captured beetles that arrived early (pioneers) and late on slash pine trees, Pinus elliottii, and measured pheromone amounts in their hindguts. We marked gallery entrances of beetles as they landed on a tree and measured their reproductive success after the attack terminated. We found no difference in body size or pheromone amounts between early and late arrivers. Most beetles arrived at the middle of the attack sequence, and excavated longer galleries per day than early arrivers. The number of offspring produced per day by beetles that established galleries midway through mass attack was higher than those that arrived early or very late in the sequence. Our results suggest that beetles do not exhibit adaptive phenotypic plasticity in pre-landing pheromone production, depending on the extent of previous colonisation of a host. Rather, it appears that stabilising selection favours beetles that attack in the middle of the sequence, and contributes to attack synchrony. Synchronous attack on trees is essential before population booms characteristic of tree-killing bark beetles can occur in nature.     

Temperature-dependent parameters of stridulatory signals in the four-eyed fir bark beetle,Polygraphus proximus (Coleoptera: Curculionidae: Scolytinae)

Acoustic signals are an essential part of the multi-modal systems of conspecific communication among insects. The patterns of abiotic factors effects on their communication parameters are of great interest for prognostic purposes in current climatic instability and for practical application in order to manage their populations.The aim of this study was to reveal the dependence of the parameters of acoustic signals produced by bark beetle Polygraphus proximus, an aggressive alien stem pest on the environmental temperature. Male stridulatory signals were recorded in seven temperature settings (5–35 °C), and changes in their temporal parameters were evaluated under laboratory conditions.The obtained results allowed us to reveal the pattern of temperature dependence of signals produced by P. proximus. More than half of the insects were found to actively stridulate at 5 °C. Raising temperature caused an increment in chirp rate that continued to increase up to 30 °C. Further temperature increase led to suppression of signaling in most of the tested males. The obtained results showed a number of patterns of temperature effect on the parameters of acoustic signals which might be universal for representatives of different bark beetles genera with various stridulatory apparatus types.     

Allolarinus,a new genus and species of Lixini (Coleoptera: Curculionidae: Lixinae) from Congo

A new weevil genus, Allolarinus n. gen., with type species, Allolarinus demeyeri n. sp., is described from Congo in the tribe Lixini. The illustrations and diagnostic characteristics of this genus have been presented in a table and figure plates. This new genus is related to Larinus Dejean in terms of the type of elytra and general shape of the prothorax but clearly differs from Larinus with respect to its tooth-bearing femora and granulose pronotum. The trapezoidal short-neck prothorax and general shape of the elytra of this new genus are similar to those of Larinus; the granulose pronotum to that of Lixomorphus Faust; the dentate femora to that of Holcolixus Voss, Erilixus Voss, and Sublarinus Petri; while the existing cubito-anal vein on metathoracic wings to those of Allolixus Voss.     

Olemehlia krali,a new genus and species of Ripidiinae from Baltic amber (Coleoptera: Ripiphoridae)

A new genus and species, Olemehlia krali n. g. & n. sp. (Coleoptera: Ripiphoridae: Ripidiinae), is described from Baltic amber. The newly described genus is compared with all known fossil and extant closely related genera of the subfamily Ripidiinae. It is characterised by the following combination of characters: antennae consisting of 10 antennomeres, with scape, pedicel, and antennomere 3 simple and antennomeres 4–10 uniflabellate, mouthparts reduced to a small single unpaired tubercle, postocular ommatidia absent, pronotum trapezoid without grooves or impressions, elytra without white apical spots, tarsal formula 5–5–4, hind tarsomere I shorter than three remaining combined. Diversity of Ripiphoridae in Baltic amber is discussed; key to Ripidiinae genera from Baltic amber is provided.     

Historical demography and phylogeography of a specialist bark beetle, Dendroctonus pseudotsugae Hopkins (Curculionidae: Scolytinae)

Contemporary distribution of North American species has been shaped by past glaciation events during the Quaternary period. However, their effects were not as severe in the southern Rocky Mountains and Northern Mexico as elsewhere in North America. In this context, we test hypotheses about the historical demography of Dendroctonus pseudotsugae, based on 136 haplotypes of mitochondrial cytochrome oxidase I. The phylogenetic analysis yielded four haplogroups corresponding to northwestern United States and southwestern Canada (NUS), southwestern United States (Arizona, SUS), northwestern Mexico (Sierra Madre Occidental, SMOC), and northeastern Mexico (Sierra Madre Oriental, SMOR). Predictions of demographic expansion were examined through neutrality tests against population growth and mismatch distribution. Results showed that the NUS and SMOC haplogroups have experienced demographic expansion events, whereas the SUS and SMOR haplogroups have not. Divergence times between pairs of haplogroups were estimated from early to middle Pleistocene. The longer divergence time between NUS and all other haplogroups could be the result of refugia within the Pacific Northwest and northern Rocky Mountains and long-term isolation from southernmost populations in Mexico. The results obtained in this study are in agreement with the evolutionary history of the host Douglas-fir, as the warmer climates of interglacial periods pushed conifers northward of Colorado, New Mexico, and Arizona, whereas environmental changes reduced the population size of Douglas-fir and forced fragmentation of distribution range southward into northern Mexico.     

Deep phylogenetic divergence between Scolytoplatypus and Remansus,a new genus of Scolytoplatypodini from Madagascar (Coleoptera,Curculionidae, Scolytinae)

Scolytoplatypodini Blandford is a monotypic tribe of ambrosia beetles found in Asia, Madagascar and Africa. Only three species are currently known from Madagascar and four additional species are here described as new to science. Phylogenetic analyses of morphological and molecular data revealed that four of the seven endemic species are deeply separated from all other species by genetic and distinct morphological characters and therefore placed in a new genus Remansus Jordal. The split between this ancient lineage and Scolytoplatypus Schaufuss was estimated to approximate Palaeocene age (63 Ma), extending the minimum age of ambrosia feeding for this tribe to the beginning of the Palaeocene‒Eocene thermal maximum (PETM). In addition to the ancient origin of Remansus in Madagascar during the Palaeocene, a second origin occurred in Scolytoplatypus no more than 13 Ma. A geographical origin of the latter in South-Eastern Africa was unequivocally inferred from the phylogenies.     

The new genus Pheude (Coleoptera,Curculionidae, Cossoninae) with description of a new species from mainland China

A new weevil, Pheude punctatus gen. et sp. n., of the tribe Dryotribini in Cossoninae, is described from Guangdong Province, South China. It differs from the related genera Dryotribus Horn and Microtribodes Morimoto in having antennae with seven articles and a distinct scutellum, and from Ochronanus Pascoe and Stenomimus Wollaston in having long antennae, a rostrum with a medio-longitudinal furrow beginning at the posterior margin of the eyes and extending approximately midway on the rostrum, and a moderately elevated, medio-longitudinal carina extending the full length of the pronotum. Other diagnostic characters and illustrations are provided. A key to the genera of Dryotribini known from China is given.     

Phylogeny of Dendroctonus bark beetles (Coleoptera: Curculionidae: Scolytinae) inferred from morphological and molecular data

Bark beetles in the genus Dendroctonus may attack and kill several species of coniferous trees, some of them causing major economic losses in temperate forests throughout North and Central America. For this reason, they have been widely studied. However, various aspects of the taxonomy and evolutionary history of the group remain contentious. The genus has been subdivided in species groups according to morphological, biological, karyological or molecular attributes, but the evolutionary affinities among species and species groups within the genus remain uncertain. In this study, phylogenetic relationships among Dendroctonus species were reassessed through parsimony‐based cladistic analysis of morphological and DNA sequence data. Phylogenetic inference was based on 36 morphological characters and on mitochondrial DNA sequences of the cytochrome oxidase I (COI) gene. Analyses were carried out for each dataset, as well as for the combined data analysed simultaneously, under equal and implied weights. According to the combined analysis, the genus Dendroctonus is a monophyletic group defined by at least three synapomorphic characters and there are four main lineages of varied composition and diversity within the genus. Within these lineages, several monophyletic groups match, to some extent, species groups defined by previous authors, but certain groups proposed by those authors are polyphyletic or paraphyletic.     

A new species of derelomine weevils (Coleoptera,Curculionidae, Curculioninae: Acalyptini) from the Rovno amber

Protoceletes hirtus sp. nov. (Curculionidae: Curulioninae: Acalyptini) from the Late Eocene Rovno amber is described. This is the second fossil of the genus. The new species is close to P. wolfschwenningerae Rheinheimer, 2007 from Baltic amber and differs it in the separated coxae, asymmetrically convex eyes, longer and clearly semierect hairs on the surface, and the longer body.     

Lack of genetic differentiation in aggressive and secondary bark beetles (Coleoptera: Curculionidae, Scolytinae) from Arizona

Bark beetles (Coleoptera: Curculionidae, Scolytinae) play an important role as disturbance agents in ponderosa pine (Pinus ponderosa Douglas ex Lawson) forests of Arizona. However, from 2001 to 2003, elevated bark beetle activity caused unprecedented levels of ponderosa pine mortality. A better understanding of the population structure of these species will facilitate analysis of their dispersal patterns and improve management strategies. Here, we use fluorescently labeled amplified fragment length polymorphism (fAFLP) analysis to resolve genetic variation among and within sampling locations in northcentral Arizona of Ips pini (Say), Dendroctonus brevicomis LeConte, and D. frontalis Zimmermann. We generated genetic fingerprints for >500 beetle specimens and analyzed genetic diversity. For all species, gene flow estimates among sampling locations were high, and significant population subdivision was not discernible across a large portion of ponderosa pine forests in Arizona. However, a weak relationship was detected with I. pini population structure and elevation. Because of the lack of genetic differentiation detected throughout the large study area, our findings suggest these insects are capable of long distance dispersal and exhibit a high degree of gene flow across a broad region. We conclude that our results are consistent with strong dispersal patterns and large population sizes of all three species.     

Areography of the genus Dendroctonus (Coleoptera: Curculionidae: Scolytinae) in Mexico

Objective To analyse whether the geographical ranges of Dendroctonus species are (1) associated with factors such as host species or elevation, and (2) in agreement with Halffter's Nearctic distribution pattern. (3) To identify and discuss the factors that are likely to act as barriers to the genus’ geographical distribution. (4) To explore whether there is an association between the size of the geographical ranges of Dendroctonus species and the number of Pinus host species used by each of them, and (5) to assess if these host species are most common at the elevations preferred by the individual Dendroctonus species. Site Mexico. Methods Records of 12 species of Dendroctonus were gathered from entomological collections in Mexico. Distribution ranges were defined by using the propinquity method ( Rapoport, 1975a ). Analysed parameters were: (1) geographical distribution of single species, (2) overlapping of species ranges, (3) disjunction patterns and barriers by means of isoprobabilistic lines, based on the morphotectonic subdivision of Mexico ( Ferrusquía‐Villafranca, 1998 ), (4) spatial variation in species richness with respect to latitude and altitude, (5) size of geographical ranges, and (6) host species for each Dendroctonus species. A correlation was determined between area size and number of pine host species. Results The species ranges varied in shape and size. Geographical ranges tend to be discontinuous in shape. Composite patterns showed that disjunctions among ranges do not closely follow Mexico's morphotectonic subdivision. There are repeated discontinuities among individual distributions, which define five areas: (1) Baja California Peninsula, (2) Sierra Madre Occidental (SMOC), (3) northern Sierra Madre Oriental (SMOR), (4) Sierra Madre de Chiapas, and (5) SMOR + Faja Volcanica Transmexicana (FVT) + Sierra Madre del Sur. The isoprobabilistic lines confirm that the inner part of SMOC provides an optimal environment for the genus, and the FVT province constitutes the broader corridor for it in the country. Richness does not directly decrease or increase with latitude. Richness behaviour of the insect is not associated with that of its host. Elevation distributions showed that most Dendroctonus species move within broad margins of tolerance and species richness is concentrated in the montane interval. Dendroctonus attack 24 of the 47 Pinus species distributed in Mexico. Preferred pine species belong predominantly to Leiophyllae, Ponderosae and Oocarpae subsections. The Spearman rank correlation between area size and number of pine host species was not significant. Dendroctonus clearly belongs to a Nearctic distribution pattern (sensu Halffter, 1987 ). Main conclusions Dendroctonus is present in all montane systems of Mexico and its species coexist within a high geographical sympatry. Overlapping of species distribution appears to be the result of two elements – generalized polyphagy inside Pinus and a wide elevation tolerance within mountainous environments. This behaviour, linked to a high vagility, has allowed the genus Dendroctonus to expand its distribution across Mexico and to employ mountainous systems as corridors separated by barriers that exert a low selective filter effect.     

A new genus and nine new species of Eugnomini (Coleoptera,Curculionidae) from New Caledonia

The genus Rasilinus gen. n. is described (type species Rasilinus tchambicus sp. n.). Nine new species: Rasilinus bicolor sp. n., Rasilinus bifurcatus sp. n., Rasilinus bimaculatus sp. n., Rasilinus grandidens sp. n., Rasilinus longulus sp. n., Rasilinus subgemellus sp. n., Rasilinus subnodulus sp. n., Rasilinus tchambicus sp. n., Rasilinus virgatus sp. n. are described from New Caledonia. Illustrations of the external morphology, male and female terminalia, dorsal habitus colour photographs of the adults, key to species and distribution map of the new genus Rasilinus are provided.