The unique locomotor apparatus of whirligig beetles of the tribe Orectochilini (Gyrinidae,Coleoptera)

Whirligig beetles, which are known for their rapid gliding on the water surface, have evolved a unique locomotor apparatus. External and internal thoracic structures of Orectochilus villosus (Orectochilini) are described in detail and documented with microcomputed tomography, computer‐based 3D reconstructions, and scanning electronic microscopy (SEM). The results are compared with conditions found in other genera of Gyrinidae and other groups of Coleoptera. The focus is on structures linked with locomotion, especially on the unusual flight apparatus, which differs strongly from that of other beetles. As in the other Orectochilini, the prothorax of Orectochilus displays characters typical for Gyrinidae, with triangular procoxae and forelegs transformed into elongated, sexually dimorphic grasping devices. The musculature of this segment is similar to the pattern found in other Coleoptera. Similar to all other extant Gyrinidae, the mesothorax is characterized by an extensive and flat mesoventrite, suitable for gliding on the water surface. As in Heterogyrinae and the other Gyrininae, the pterothoracic legs are transformed into paddle‐like structures, enabling the beetles to move with high speed on the surface film. The musculature of the mesothorax is reduced compared to other Coleoptera, but similar to what is found in the other Gyrininae. The metathoracic skeleton and musculature are simplified in Orectochilini compared to other Gyrininae and other groups of Coleoptera. In O. villosus, only 10 metathoracic muscles are preserved. 36 are present in an archostematan beetle, a condition probably close to the coleopteran ground plan. The metathoracic dorsal longitudinal bundles are absent in Gyrininae, muscles that play a role as indirect flight muscles in most other neopteran insects. The rest of the posteromotoric flight apparatus is distinctly modified, with a limited number of skeletomuscular elements taking over more functions. The large muscle M84 (IIIdvm7) M. noto–trochanteralis, for instance, functions as dominant wing levator, but is also responsible for the powerful and rapid backstroke of the hind legs. The presence of this muscle is a synapomorphy of Heterogyrinae and Gyrininae. The narrow metafurca in the latter group is likely linked to its large size. The elytra likely contribute to the control of the flight of the beetle, whereas they shield and inhibit the flight apparatus during swimming.     

The New World whirligig beetles of the genus Dineutus Macleay, 1825 (Coleoptera,Gyrinidae, Gyrininae,Dineutini)

All New World members of the whirligig beetle genus Dineutus Macleay, 1825 are treated. The New World Dineutus are found to be composed of 18 species and 6 subspecies: one species, Dineutusmexicanus Ochs, 1925, stat. n. is elevated from subspecies to species rank, and the subspecies Dineutuscarolinusmutchleri Ochs, 1925, syn. n. is synonymized here with the typical form. Lectotypes are designated for Dineutusdiscolor Aubé, 1838, Dineutesmetallicus Aubé, 1838, Dineutussolitarius Aubé, 1838, Dineutesanalis Régimbart, 1883, and Gyrinuslongimanus Olivier, 1795. Each taxonomic unit is provided with a taxonomic history, type locality, diagnosis, distribution, habitat information, and a discussion section. The aedeagus and male mesotarsal claws are illustrated, and dorsal and ventral habitus images of both sexes, for each species and subspecies are provided. General distribution maps are provided for all taxonimc units. A key to the genera of New World Gyrinidae, as well as all the New World Dineutus species is provided. General Dineutus anatomy as well as a clarification of homology and anatomical terms is included.     

Phylogeny and classification of whirligig beetles (Coleoptera: Gyrinidae): relaxed‐clock model outperforms parsimony and time‐free Bayesian analyses

Phylogenetic relationships among members of the family Gyrinidae (Coleoptera: Adephaga) were inferred from analysis of 42 morphological characters and DNA sequence data from the genes 12S rRNA, cytochrome c oxidase I and II, elongation factor 1 alpha (2 different copies) and histone III. Eighty‐nine species of Gyrinidae were included representing all known subfamilies, tribes and genera. Outgroups include species from Noteridae, Paelobiidae and Dytiscidae. Analyses include parsimony analysis, and partitioned time‐free and relaxed‐clock Bayesian analyses of the combined data using reversible‐jump MCMC to simultaneously integrate over all possible 4 × 4 nucleotide substitution models. Analyses resulted in conflicting topologies between the combined parsimony and Bayesian analyses on the one hand, and the relaxed‐clock analysis on the other. The marginal likelihoods of competing models were calculated with stepping‐stone sampling and used in a Bayes factor test, which, along with arguments from morphology, supported the topology generated by the relaxed‐clock analysis. This phylogenetic hypothesis is adopted to revise the higher classification of Gyrinidae. Major taxonomic conclusions include: (i) monophyletic Gyrinidae, (ii) the Nearctic Spanglerogyrinae Folkerts (with one species, Spanglerogyrus albiventris Folkerts) sister to all other Gyrinidae, (iii) the Madagascar endemic Heterogyrinae Brinck stat. n. (with one species, Heterogyrus milloti Legros) sister to all Gyrinidae except Spanglerogyrinae, (iv) monophyletic Gyrininae Latreille including three monophyletic tribes with the following relationship: Orectochilini Régimbart + (Gyrinini Latreille + Enhydrini Régimbart), (v) monophyletic Orectochilini comprising four monophyletic genera with the following relationships: (Gyretes Brullé + Patrus Aubé stat. n. ) + (Orectogyrus Régimbart + Orectochilus Dejean), (vi) monophyletic Gyrinini comprising three genera with the following relationships: Gyrinus Geoffroy + (Metagyrinus Brinck + Aulonogyrus Motschulsky), each monophyletic except Metagyrinus with only one included species and not tested for monophyly, and (vii) monophyletic Enhydrini comprising five genera with the following relationships: (Porrorhynchus Laporte + Dineutus MacLeay) + (Enhydrus Laporte + (Andogyrus Ochs + Macrogyrus Régimbart)), each monophyletic except Porrorhynchus, Enhydrus and Andogyrus each with one included species and untested for monophyly. Each subfamily, tribe and genus is diagnosed and discussed. The female reproductive tract of each group is presented, illustrated and discussed with respect to the phylogenetic conclusions.     

Embryonic development of a whirligig beetle,Dineutus mellyi,with special reference to external morphology (insecta: Coleoptera,Gyrinidae)

The egg morphology and successive changes of developing embryos of the whirligig beetle, Dineutus mellyi (Adephaga: Gyrinidae) are described from observations based on light and scanning electron microscopy. The egg surface is characterized by minute conical projections covering the entire egg surface, a stalk‐like micropylar projection at the anterior pole of the egg, and a longitudinal split line along which the chorion is cleaved during the middle embryonic stages. The germ band or embryo is formed on the ventral egg surface, and develops on the surface throughout the egg period; thus, the egg is a superficial type, as is the case in most coleopteran species. A pair of lateral tracheal gills (LTGs) of the first abdominal segment originates from appendage‐like projections arising at the lateral side of pleuropodia, and the LTGs of the second to ninth abdominal segments are arranged in a row with that of the first segment. Therefore, LTGs are structures with serial homology. The paired dorsal tracheal gills (DTGs) of the ninth abdominal segment are formed on the regions just latero‐dorsal to the LTGs of this segment. Regarding the pleuropodia as the structures being homologous with thoracic legs, neither the LTGs nor DTGs are homologous with thoracic legs, but originate in the more lateral region corresponding to the future pleura of the thoracic segments. The last (10th) abdominal segment in the larva is formed by the fusion of the embryonic 10th and 11th abdominal segments. Four terminal hooks at the end of the last abdominal segment originate from two pairs of swellings on the posterior end of the embryonic 11th abdominal segment. It is proposed that the terminal hooks possibly correspond to the claws of medially fused cerci of the embryonic 11th abdominal segment. J. Morphol. 2012. © 2012 Wiley Periodicals, Inc.     

Attachment site and infestation parameters of parasitic water mites on the whirligig beetle Dineutus nigrior Roberts (Coleoptera: Gyrinidae)

Larval water mites parasitise a wide range of aquatic insects and may have a negative impact on host fitness. One host taxon susceptible to water mite parasitism is the whirligig beetle (Coleoptera: Gyrinidae). We made 11 collections of the whirligig beetle Dineutus nigrior Roberts from May to October of 2006 to investigate patterns of water mite parasitism on that host species. Mites were identified as of the genus Eylais. Mite intensity ranged from 1 to 11. Median intensity was 1.0 and ranged from 1.0 to 3.0 for individual samples. There did not appear to be temporal patterns in mite intensity. Prevalence was 30.9% but varied substantially over the sampling period ranging from 2.5 to 63.3%. Mites were attached to the metathoracic wings and the body tergites under the elytra. When all samples were considered there was equal use of wings and body tergites but there was temporal variation in the use of attachment sites.     

Alarm substance in Gyrinus aeratus (Coleoptera,Gyrinidae)

Gyrinid beetles are common in ponds and lakes in Sweden, where they aggregate in open areas of the surface. Gyrinid beetles have pygidial glands which produce compounds rendering them unpalatable to fish. This study examines whether the pygidial secretion can be used for alarm purposes in addition to other functions. Experiments showed that gyrinid beetles responded to water prepared with the pygidial compounds by evasive behaviour. The beetles did not respond when the compound was mediated by air. One component of the defense system of gyrinids is how they advertise their presence. The aggregation of dark beetles with their typical motion pattern when alerted is very conspicuous and easily identified by an experienced predator. We suggest that this aspect of gyrinid defence can be characterized as aposematic.     

A taxonomic review of the Gyrinidae (Coleoptera) in Korea

A taxonomic review of Korean Gyrinidae is presented. Seven species [Dineutus orientalis (Modeer, 1776), Gyrinus gestroi Régimbart, 1883, Gyrinus japonicus Sharp, 1873, Gyrinus pullatus Zaitzev, 1908, Orectochilus punctipennis Sharp, 1884, Orectochilus Regimbarti Sharp, 1884 and Orectochilus villosus (Müller, 1776)] in three genera are recognized, one of which (Orectochilus punctipennis Sharp, 1884) is reported for the first time in Korea. We also found that Gyrinus curtus Motschulsky, 1866 previously recorded in Korea was an incorrect identification of Gyrinus pullatus Zaitzev, 1908. Habitus and SEM photographs, distribution maps, keys, and diagnoses of genera and species are provided.     

Larval morphology and chaetotaxy of Macrogyrus oblongus (Boisduval, 1835) (Coleoptera: Gyrinidae)

The larvae of the grooved whirligig beetle Macrogyrus oblongus (Boisduval, 1835) are described and illustrated including detailed morphometric and chaetotaxic analyses of selected structures. Larvae of Macrogyrus Régimbart, 1882 Régimbart, M. (1882), ‘Essai Monographique de la Famille des Gyrinidae. 1re partie’, Annales de la Société entomologique de France, 51, 379–458. [Google Scholar] exhibit the characters traditionally recognised as autapomorphies of the Gyrinidae. The first instars bear egg bursters on the parietal, a potential additional autapomorphy. Putative larval autapomorphies of the tribe Dineutini are the presence of additional setae on the mandible, the absence of the seta TR2, and the presence of pore-like additional structures on the ultimate palpomeres. Macrogyrus larvae differ from those of the other known dineutine genera (Andogyrus Ochs, 1924 and Dineutus MacLeay, 1825) in the absence of a neck constriction and in the distal position of the pore LAc. Other useful characters to distinguish genera within Dineutini are the presence or absence of additional setae on the cardo and coxa, and the posterior margin of the lacinia dentate or smooth.     

A catalogue of Lithuanian beetles (Insecta, Coleoptera)

This paper presents the first complete and updated list of all 3597 species of beetles (Insecta: Coleoptera) belonging to 92 familiesfound and published in Lithuania until 2011, with comments also provided on the main systematic and nomenclatural changes since the last monographic treatment in two volumes (Pileckis and Monsevičius 1995, 1997). The introductory section provides a general overview of the main features of the territory of Lithuania, the origins and formation of the beetle fauna and their conservation, the faunistic investigations in Lithuania to date revealing the most important stages of the faunistic research process with reference to the most prominent scientists, an overview of their work, and their contribution to Lithuanian coleopteran faunal research.Species recorded in Lithuania by some authors without reliable evidence and requiring further confirmation with new data are presented in a separate list, consisting of 183 species. For the first time, analysis of errors in works of Lithuanian authors concerning data on coleopteran fauna has been conducted and these errors have been corrected. All available published and Internet sources on beetles found in Lithuania have been considered in the current study. Over 630 literature sources on species composition of beetles, their distribution in Lithuania and neighbouring countries, and taxonomic revisions and changes are reviewed and cited. An alphabetical list of these literature sources is presented. After revision of public beetle collections in Lithuania, the authors propose to remove 43 species from the beetle species list of the country on the grounds, that they have been wrongly identified or published by mistake. For reasons of clarity, 19 previously noted but later excluded species are included in the current checklist with comments. Based on faunal data from neighbouring countries, species expected to occur in Lithuania are matnioned. In total 1390 species are attributed to this category and data on their distribution in neighbouring countries is presented. Completion of this study provides evidence that the Lithuanian coleopteran fauna has yet to be completely investigated and it is estimated that approximately 28 % of beetle species remain undiscovered in Lithuania. More than 85% of beetle species expected for Lithuania have been found in the following families: Cerylonidae, Geotrupidae, Haliplidae, Kateridae, Lycidae, Lucanidae, Mycetophagidae, Scarabaeidae and Silphidae. In families with few species such as Alexiidae, Boridae, Byturidae, Dascilidae, Drilidae, Eucinetidae, Lampyridae, Lymexilidae, Megalopodidae, Nemonychidae, Nosodendridae, Noteridae, Orsodacnidae, Pyrochroidae, Pythidae, Psephenidae, Rhysodidae, Sphaeritidae, Sphaeriusidae, Sphindidae, Stenotrahelidae and Trogidae, all possible species have already been discovered. However in some beetle families such as Aderidae, Bothrideridae, Eucnemidae, Laemoploeidae, Mordellidae, Ptiliidae, Scraptidae and Throscidae less than 50% of all possible species are known. At present the beetle species recorded in Lithuania belong to 92 families, with species from 9 other families such as Agyrtidae, Biphylidae, Deradontidae, Mycteridae, Ochodaeidae, Phleophilidae, Phloeostichidae, Prostomidae, Trachypachidae are expected to be found.A bibliography and a index of subfamily and genus levels are provided. The information published in the monograph will serve to further faunistic and distribution research of beetles and will help to avoid confusion in the identificatation of coleopteran fauna of Lithuania.     

Feeding behavior of leaf beetles (Coleoptera,Chrysomelidae)

The feeding behavior of adult leaf beetles (41 species from 18 genera and 8 subfamilies) was studied for the first time. Beetles of the genera Chrysolina, Chrysomela, Cryptocephalus, Galeruca, Gastrophysa, Labidostomis, Leptinotarsa, Timarcha, and Cassida stigmatica gnaw a leaf from the edge, whereas the representatives of Donacia, Galerucella, Lema, Lilioceris, Oulema, Phyllobrotica, Plagiodera, Zeugophora, Hypocassida, and most species of Cassida gnaw the leaf plane. In addition, adults of Lilioceris merdigera and Donacia clavipes feed on young leaves rolled into a tube. New host plants are reported for the first time: Hyoscyamus niger for the larvae of the Colorado potato beetle and Naumburgia thyrsiflora for Galerucella grisescens.     

Ground beetles of the Ukraine (Coleoptera, Carabidae)

A review of the ground beetles of the Ukrainian fauna is given. Almost 750 species from 117 genera of Carabidae are known to occur in the Ukraine. Approximately 450 species of ground beetles are registered in the Carpathian region. No less than 300 species of ground beetles are found in the forest zone. Approximately 400 species of Carabidae present in the forest-steppe zone are relatively similar in species composition to those in the forest territories. Some 450 species of Carabidae are inhabitants of the steppe zone. Representatives of many other regions of heterogeneous biotopes such as forest, semi desert, intrazonal, etc. can be found in the steppe areas. The fauna of Carabidae (ca. 100 species) of the lowlands of southern Ukraine (sandy biotopes), situated mostly in the Kherson region, is very peculiar. The fauna of the Crimean mountains contains about 300 species. Conservation measures for the Carabidae are discussed.     

New mesozoic Ithyceridae beetles (Coleoptera)

A new subfamily, Mongolocarinae subfam. nov. of the family Ithyceridae, from the Middle-Upper Jurassic and Lower Cretaceous of Asia is described. It includes five genera with five species: Palaeocar gen. nov. (with P. princeps sp. nov.), Mongolocar gen. nov. (M. orcinus sp. nov.), Praecar gen. nov. (P. stolidus sp. nov.), Karacar gen. nov. (M. contractus sp. nov.), and Baissacar gen. nov. (B. passarius sp. nov.).     

Anthophagy in the leaf beetles (Coleoptera,Chrysomelidae)

Laboratory experiments were performed on leaf beetles collected on flowers. Flower consumption (anthophagy) was demonstrated for adults of Donacia bicolora, D. brevitarsis, D. obscura, D. thalassina, Plateumaris discolor, Cryptocephalus laetus, C. sericeus, C. solivagus, Labidostomis longimana, Hydrothassa marginella, Phaedon concinnus, Galerucella nymphaeae, Neocrepidodera femorata, Altica oleracea, Aphthona lutescens, Longitarsus pellucidus, and larvae of Entomoscelis adonidis, H. marginella, and G. nymphaeae for the first time for all the species except for P. discolor, L. longimana, and C. sericeus. The feeding behavior was described, and the mouthparts of adults were studied. The mandibles and maxillae of the Donacia, Plateumaris, and Orsodacne species mentioned are adapted to consuming pollen. Some questions of ecology and evolution of anthophagy are discussed. An overview of literature on anthophagy in the leaf beetles is presented.     

瓢虫性选择行为及进化机制研究

昆虫性选择行为一直是行为生物学家和进化生物学家所关注的热点。早期对瓢虫性选择行为研究主要集中在非随机性交配模式,随着研究的深入,近些年对瓢虫性选择行为研究取得了许多新成果,包括多次交配的行为机制、性选择的识别机制、精子传送及竞争等。为全面地了解瓢虫性选择行为研究现状,本文总结了瓢虫非随机性交配模式,综述了近十余年对瓢虫性行为及进化的研究成果,同时对瓢虫性选择行为未来的研究方向进行了展望。     

On the systematic position of the family Gyrinidae (Coleoptera: Adephaga)

Various characters of adult and larval members of Adephaga and Cupedidae were analyzed, and suggest that Gyrinidae are the sister-group of the remaining Adephaga, and are not closely related to the remaining aquatic Adephaga. The aquatic families Noteridae, Amphizoidae, Hygrobiidae and Dytiscidae seem to form a well founded monophyletic unit. The following characters are considered as synapomorphies of Adephaga excluding Gyrinidae: bifurcate condition of the muscle (= M.) tentoriopraementalis inferior, reduction of hypopharynx, strongly developed prosternal process, reduction in size and specialized modification of the ventral sclerite of the mesothorax, strongly developed mesofurcal arms, a high mesopleural ridge, globular mesocoxae restricted to rotatory movements, invaginated sternum VIII (coxostemum), the strongly curved base of the median lobe of the aedeagus, which articulates with the parameres, the rotated position of the aedeagus in repose, fusion of the larval clypeolabrum with the frons and reduction of the larval lacinia. Mesal shifting of M. episterno-coxalis prothoracis, and the fusion of the apical portions of the malpighian tubules of either side are considered as synapomorphies of Adephaga excluding Rhysodidae and Gyrinidae. Lateral reduction of the meta “sternal” transverse ridge and the presence of the subcubital setal binding patch of the hind wing are considered as synapomorphic characters of Trachypachidae, Noteridae, Amphizoidae, Hygrobiidae and Dytiscidae. We postulate that the metacoxal fusion occurred independently in gyrmids and the common ancestor of Trachypachidae, Noteridae, Amphizoidae, Hygrobiidae and Dytiscidae. Consequently we consider this character state as another synapomorphy of Trachypachidae and Hydradephaga excluding Haliplidae and Gyrinidae. The following characters are considered as synapomorphies of Noteridae, Amphizoidae, Hygrobiidae and Dytiscidae: Loss of tactile setae on the head capsule, metafurcal origin on the intercoxal wall, expansion of the intercoxal wall, elongation of the subcubital setal binding patch, loss of Mm. furca-coxale anterior and posterior, reduction of the larval abdominal segments IX and X, and the shifting of the uropmphi onto the ventral side of segment VIII. Presence of M. tentorio-mandibularis and M. stipitopalpalis intemus are certainly primitive features of adult gyrinids but the distribution of these character states among most members of Adephaga is yet unclear. Chemical defence gland constituents point towards a very isolated position of Gyrinidae. The old age of the group, documented by a larva found in upper Permian deposits, may support the hypothesis of a sister-group relation-ship between Gyrinidae and the remainder of Adephaga.     

The ladybird beetles (Coleoptera,Coccinellidae) of Moscow Province

Data on the fauna and ecology of the ladybird beetles (Coleoptera, Coccinellidae) of Moscow Province are summarized. In total, 60 species of 29 genera are recorded for this region. The paper is provided with 30 original color photographs of 29 species representing all the genera known from Moscow Province.     

New mesozoic diving beetles (Coleoptera,Dytiscidae) from China

A new subfamily of predaceous diving beetles, Liadytiscinae subfam. nov., including two genera and four species, Liadytiscus gen. nov. (L. cretaceus sp. nov., L. longitibialis sp. nov., and L. latus sp. nov.) and Liadroporus gen. nov. (L. elegans sp. nov.), from the Late Tithonian-Berriasian (Huangbanjigou, Yixian Formation) of China is described. Two new genera, Mesoderus gen. nov. with two species, M. magnus sp. nov. and M. ventralis sp. nov., and Sinoporus gen. nov. with one species, S. lineatus sp. nov., are also described; their position in the system of Dytiscidae remains uncertain. Relationships of the taxa described with Recent and fossil taxa of the same rank and some presumable ecological features of the new taxa are discussed.     

Integration of visual and olfactory cues of hosts and non-hosts by three bark beetles (Coleoptera: Scolytidae)

Abstract.  1. There has been a long-standing pre-occupation with how phytophagous insects use olfactory cues to discriminate hosts from non-hosts. Foragers, however, should use whatever cues are accurate and easily assessed, including visual cues.
2. It was hypothesised that three bark beetles, the mountain pine beetle (MPB), Dendroctonus ponderosae Hopkins, the Douglas-fir beetle (DFB), D. pseudotsugae Hopkins, and the western balsam bark beetle (WBBB), Dryocoetes confusus Swaine, integrate visual and olfactory information to avoid non-host angiosperms (e.g. paper birch, trembling aspen), that differ in visual and semiochemical profile from their respective host conifers (lodgepole pine, Douglas-fir, interior fir), and tested this hypothesis in a series of field trapping experiments.
3. All three species avoided attractant-baited, white (non-host simulating) multiple-funnel traps, and preferred attractant-baited black (host-simulating) traps. In experiments combining white, non-host traps with non-host angiosperm volatiles, bark beetles were repelled by these stimuli in an additive or redundant manner, confirming that these species could integrate visual and olfactory information to avoid non-host angiosperms while flying.
4. When antiaggregation pheromones were released from white traps, the DFB and MPB were repelled in an additive-redundant manner, suggesting that beetles can integrate diverse and potentially anomalous stimuli.
5. The MPB demonstrated the most consistent visual preferences, suggesting that it may be more of a 'visual specialist' than the DFB or WBBB, for which visual responses may be more contingent on olfactory inputs.     

Habitat selection and grouping of beetles (Coleoptera)

Beetles were collected by pitfall trapping for a two-year period in seven adjacent habitats in an upland site in North Wales. Positive correlations were demonstrated between number of beetle species and number and diversity of plant species. Similar correlations were shown between beetle numbers and plant species. However, only 15% of the beetle species were herbivores requiring host plants. The degree of habitat selection by individual beetle species was demonstrated, ranging from habitat specialist, being found in one habitat, lo habitat generalist, being found in most habitats. Herbivores were significantly more habitat specialist than predators or scavengers. The grouping of beetles, demonstrated by ordination analysis, was similar to, but less precise than, the grouping of plant species. The beetle groups reflect habitat selection preferences by individual species rather than a functional relationship between beetle species. They provide an example of the centrifugal structure of habitat selection theory.