Predaceous diving beetles (Coleoptera: Dytiscidae) of Jordan

The first account of the predaceous diving beetles or Dytiscidae of Jordan is presented. Altogether 25 species are listed, although the occurrence of two of them remains doubtful. Nine species are recorded from the territory of Jordan for the first time, and the first precise locality data are provided for an additional seven species. Bidessus anatolicus Wewalka, 1972 and Nebrioporus stearinus (Kolenati, 1845) recorded recently from Jordan based on misidentification are removed from the list. If available, habitat information is provided for recently collected species. The zoogeographical patterns of the region are briefly summarised.     

Speciation of Iberian diving beetles in Pleistocene refugia (Coleoptera, Dytiscidae)

The Mediterranean basin is an area of high diversity and endemicity, but the age and origin of its fauna are still largely unknown. Here we use species-level phylogenies based on approximately 1300 base pairs of the genes 16S rRNA and cytochrome oxidase I to establish the relationships of 27 of the 34 endemic Iberian species of diving beetles in the family Dytiscidae, and to investigate their level of divergence. Using a molecular clock approach, 18-19 of these species were estimated to be of Pleistocene origin, with four to six of them from the Late Pleistocene ( approximately 100 000 years). A second, lower speciation frequency peak was assigned to Late Miocene or Early Pliocene. Analysis of the distributional ranges showed that endemic species placed in the tip nodes of the trees are significantly more likely to be allopatric with their sisters than endemic species at lower node levels. Allopatric sister species are also significantly younger than sympatric clades, in agreement with an allopatric mode of speciation and limited subsequent range movement. These results strongly suggest that for some taxa Iberian populations were isolated during the Pleistocene long enough to speciate, and apparently did not expand their ranges to recolonize areas north of the Pyrenees. This is in contradiction to observations from fossil beetles in areas further north, which document large range movements associated with the Pleistocene glacial cycles hypothesized to suppress population isolation and allopatric speciation.     

New box trap for large predaceous diving beetles Cybister Curtis, 1827 and Dytiscus Linnaeus, 1758 (Coleoptera: Dytiscidae)

A box trap was developed for effective collection of large predaceous diving beetles. The floating trap, which was fabricated from a plastic box with two funnel mouths equipped with mesh lids, can be opened only when beetles enter the trap. Considerable attention was paid to the trap's performance as it was quantitatively evaluated in laboratory conditions in detail using Cybister and Dytiscus diving beetles. Without the mesh lid on the trap mouth (negative control test), the number of beetles in the trap was the highest at 2–3 hours. However, most beetles escaped from the trap without a mesh lid within six hours of starting the experiment. When eight beetles were put into a trap without a mesh lid, all of them had escaped from it after eight hours. On the contrary, beetles did not escape from a trap with a mesh lid. This result and testing in the field suggest that trap lids have a significant role in averting the escape of beetles from the trap.     

Evolution of subterranean diving beetles (Coleoptera: Dytiscidae: Hydroporini, Bidessini) in the arid zone of Australia

Calcrete aquifers in arid inland Australia have recently been found to contain the world's most diverse assemblage of subterranean diving beetles (Coleoptera: Dytiscidae). In this study we test whether the adaptive shift hypothesis (ASH) or the climatic relict hypothesis (CRH) is the most likely mode of evolution for the Australian subterranean diving beetles by using a phylogeny based on two sequenced fragments of mitochondrial genes (CO1 and 16S-tRNA-ND1) and linearized using a relaxed molecular clock method. Most individual calcrete aquifers contain an assemblage of diving beetle species of distantly related lineages and/or a single pair of sister species that significantly differ in size and morphology. Evolutionary transitions from surface to subterranean life took place in a relatively small time frame between nine and four million years ago. Most of the variation in divergence times of the sympatric sister species is explained by the variation in latitude of the localities, which correlates with the onset of aridity from the north to the south and with an aridity maximum in the Early Pliocene (five mya). We conclude that individual calcrete aquifers were colonized by several distantly related diving beetle lineages. Several lines of evidence from molecular clock analyses support the CRH, indicating that all evolutionary transitions took place during the Late Miocene and Early Pliocene as a result of aridification.     

Taxonomic review of the genus Copelatus Erichson (Coleoptera: Dytiscidae) in Korea

A taxonomic review of the genus Copelatus Erichson (Coleoptera: Dytiscidae) in Korea is presented. In the present study, five species of Copelatus are recognized from Korea, including one unrecorded species, C. kammuriensis. We provide a key to the Korean species of Copelatus, diagnosis of one unrecorded species, habitus photographs, scanning electron micrographs of the elytron, and illustrations of the aedeagus.     

A taxonomic review of Korean Hydroglyphus Motschulsky (Coleoptera: Dytiscidae: Hydroporinae) with a description of new species

A taxonomic study of Hydroglyphus Motschulsky in Korea is presented. Four species are recognized including a new species, Hydroglyphus coreanus sp. nov. Hydroglyphus flammulatus (Sharp) is reported for the first time in the Korean peninsula and H. geminus (Fabricius) is a new addition to the South Korean fauna. Habitus and SEM photographs, distribution maps, and key to the Korean species are provided.     

Clypeodytes geiseri sp. n., an enigmatic Bidessini from Laos (Coleoptera: Dytiscidae,Bidessini)

Here, we describe Clypeodytes geiseri sp. n. from Champasak Province in southwestern Laos. This very distinct species belongs to the subgenus Hypoclypeus Guignot, 1950 and can be distinguished from all other Clypeodytes species by its larger size and almost completely blackish or dark ferrugineous dorsal surface, except for some weak testaceous markings on the elytra. The habitus and the median lobe of the new species are illustrated, and a map is provided. Altogether, six species of subgenus Hypoclypeus are now known from Asia.

urn:lsid:zoobank.org:pub:FC01425F-9D3A-482E-8FE4-D2BF3D4943DF     

Revision of the Neotropical Genus Hemibidessus Zimmermann (Coleoptera: Dytiscidae: Hydroporinae: Bidessini)

The genus Hemibidessus Zimmermann, 1921 is revised. Six species are recognized in the genus. Two new species are described, H. spirodiscus sp. n. from Bolivia and H. spangleri sp. n. from Argentina. A key for identifying the species is presented. The female genitalia are thoroughly illustrated and described for the first time for any species of Bidessini. Other important diagnostic structures are also illustrated including the male genitalia. A cladistic analysis is presented for 8 species (6 ingroup and 2 outgroup species) and 13 characters. A single most parsimonious cladogram was found.     

Hydrotrupes chinensis Nilsson, 2003 (Coleoptera: Dytiscidae): new records, (re)description of adult and larva,and notes on its biology

Abstract

Hydrotrupes chinensis Nilsson, 2003 Nilsson, A.N. (2003), ‘Dytiscidae. XII. A New Species of Hydrotrupes Sharp from China, an Example of Pacific Intercontinental Disjunction (Coleoptera)’, in Water Beetles of China (Vol. 3), eds. M.A. Jäch and L. Ji, Vienna: Zoologische-Botanische, Gesellschaft, pp. 284–297. [Google Scholar] described from the holotype collected in Anhui Province, China, is newly recorded from three localities in Guangdong Province, ca. 750?km southwest from the type locality. The species seems to inhabit hygropetric habitats exclusively, with diurnal larvae and nocturnal adults hidden under stones or in cracks in rock during the day; when disturbed, the adults readily jumped off the rock surface. The adult is redescribed. The larvae are described and illustrated for the first time, with detailed morphometric and chaetotaxic analyses of the cephalic capsule, head appendages, legs, last abdominal segment, and urogomphi. Whereas similar morphologically to the Nearctic endemic Hydrotrupes palpalis Sharp, 1882 Sharp, D. (1882), ‘On Aquatic Carnivorous Coleoptera or Dytiscidae’, Scientific Transactions of the Royal Dublin Society, 2, 179–1003. [Google Scholar], the first instar larva of H. chinensis distinguishes by presence of six lamellae clypeales, two additional spine-like setae both on the last abdominal segment and urogomphomere 1, and the strongly developed egg bursters.     

Subpopulations of Cryptocephalus beetles (Coleoptera: Chrysomelidae): geographically close but genetically far

Abstract. The leaf beetles Cryptocephalus coryli, C. decemmaculatus and C. nitidulus are of conservation concern and are included on the UK Biodiversity Action Plan. The distinctiveness of the disjunct remaining populations of these beetles was compared to that of more continuously distributed Cryptocephalus species. This was carried out with a view to defining evolutionary significant units (ESUs) in the rare species. A portion of the cytochrome b gene, an intergenic spacer and partial tRNA was analysed from 93 specimens of Cryptocephalus beetle (Coleoptera: Chrysomelidae). Considerable sequence divergence was apparent in all the species, even at an intersite scale when the distances between sampled localities were very small (< 1 km). Intrapopulation, intersite and interpopulation divergence observed in the rare species was reflected in the species that have a more continuous distribution, implying that dispersal ability in these species is poor and gene flow can be impeded by relatively trivial barriers to dispersal. The evidence suggests that the disjunct populations of the rare Cryptocephalus species can, tentatively, be considered as ESUs. This has important implications for management strategies and reintroductions.     

Revision of Australian Matini diving beetles based on morphological and molecular data (Coleoptera,Dytiscidae, Matinae), with description of a new species

Morphological characters and mitochondrial DNA sequence data were used to revise the Australian diving beetles in the genera Allomatus Mouchamps, 1964 and Batrachomatus Clark, 1863. As a result of these studies Allomatussyn. n. is synonymised with Batrachomatus, and Allomatus nannup Watts, 1978 from SW Australia and Allomatus wilsoni Mouchamps, 1964 from SE Victoria are transferred to Batrachomatus. The four Australian Matini species knownso far are re-described, and Batrachomatus larsonisp. n. from the Windsor Tableland in NE Queensland is described. After more than 40 years Batrachomatus wilsoni has been re-discovered in two rivers in Victoria. We delineate the species using traditionally employed morphological structures such as in the male genitalia and body size, shape and colour pattern, as well as mitochondrial cox1 sequence data for 20 individuals. Important species characters (median lobes, parameres and colour patterns) were illustrated. We provide an identification key and outline distribution and habitat preferences of each species. All Australian Matini are lotic, inhabiting permanent and intermittent streams, creeks and rivers.     

Larval morphology of Agabus clypealis (Thomson, 1867) and A. pseudoclypealis Scholz, 1933 and notes on their distribution (Coleoptera: Dytiscidae)

The third instar larvae of Agabus clypealis (Thomson, 1867) and A. pseudoclypealis Scholz, 1933 are described. Important morphological structures (head, legs, and abdominal segment 8 with urogomphi) are illustrated. Both species share a completely sclerotized abdominal segment 6 with A. setulosus (J. Sahlberg, 1895). Morphological characters and species phenology are discussed in relation to the A. confinis-species group. All available literature records and some new and additional data on distribution of the two species are provided. Agabus clypealis is recorded for the first time from Estonia, and there is no reason to doubt the records of A. pseudoclypealis from Kazakhstan.     

Thermal tolerance and geographical range size in the Agabus brunneus group of European diving beetles (Coleoptera: Dytiscidae)

Aim Within clades, most taxa are rare, whilst few are common, a general pattern for which the causes remain poorly understood. Here we investigate the relationship between thermal performance (tolerance and acclimation ability) and the size of a species’ geographical range for an assemblage of four ecologically similar European diving beetles (the Agabus brunneus group) to examine whether thermal physiology relates to latitudinal range extent, and whether Brown’s hypothesis and the environmental variability hypothesis apply to these taxa. Location Europe. Methods In order to determine the species tolerances to either low or high temperatures we measured the lethal thermal limits of adults, previously acclimated at one of two temperatures, by means of thermal ramping experiments (± 1°C min^?1). These measures of upper and lower thermal tolerances (UTT and LTT respectively) were then used to estimate each species’ thermal tolerance range, as total thermal tolerance polygons and marginal UTT and LTT thermal polygons. Results Overall, widespread species have higher UTTs and lower LTTs than restricted ones. Mean upper lethal limits of the Agabus brunneus group (43 to 46°C), are similar to those of insects living at similar latitudes, whilst mean lower lethal limits (?6 to ?9°C) are relatively high, suggesting that this group is not particularly cold‐hardy compared with other mid‐temperate‐latitude insects. Widespread species possess the largest thermal tolerance ranges and have a relatively symmetrical tolerance to both high and low temperatures, when compared with range‐restricted relatives. Over the temperature range employed, adults did not acclimate to either high or low temperatures, contrasting with many insect groups, and suggesting that physiological plasticity has a limited role in shaping distribution. Main conclusions Absolute thermal niche appears to be a good predictor of latitudinal range, supporting both Brown’s hypothesis and the environmental variability hypothesis. Restricted‐range species may be more susceptible to the direct effect of climate change than widespread species, notwithstanding the possibility that even ‘thermally‐hardy’, widespread species may be influenced by the indirect effects of climate change such as reduction in habitat availability in Mediterranean areas.     

Nonlethal sampling of DNA from critically endangered diving beetles (Coleoptera: Dytiscidae) using a single antenna

Nonlethal DNA sampling is highly desirable in molecular genetic studies of protected and endangered species. To develop a demonstrably nonlethal method of obtaining DNA from endangered diving beetles (Dytiscus sharpi sharpi Wehncke, Cybister lewisianus Sharp and Cybister brevis Aubé), we amputated the antennae of these endangered diving beetles and investigated the impact of the amputation on reproductive behaviors, egg‐laying and lifespan. Diving beetles with either one or no antennae copulated without delay and laid eggs, comparable to the pairs of intact beetles under breeding conditions. The lifespan of antennae‐amputated D. sharpi sharpi was the same as that of the intact beetles. A single antenna was sufficient to allow polymerase chain reaction (PCR) detection of a mitochondrial DNA gene, cytochrome‐c oxidase subunit I (COI), and the sequence of the COI gene could be determined directly. The PCR‐ready genomic DNA was available both in fresh antennae isolated from living beetles and in old antennae from whole beetles preserved for at least 5–6 years in pure ethanol. These results suggest that an antenna is a good sampling site for isolating genomic DNA from endangered diving beetles without sacrificing and disturbing reproductive behaviors such as mating and egg‐laying, or lifespan.     

Diving beetles of the genus Liodessus Guignot, 1953 in Colombia,with description of three new species (Coleoptera: Dytiscidae)

The Colombian species of the diving beetle genus Liodessus Guignot, 1939 Guignot, F. (1939), ‘Contribution à l’étude des Bidessus’, Bulletin de la Société d’Étude des Sciences Naturelles de Vaucluse, 10(4), 51–61. [Google Scholar] are revised. Liodessus bogotensis Guignot, 1953 Guignot, F. (1953), ‘Trente-neuvième note sur les hydrocanthares’, Revue Française d’Entomologie, 20, 109–117. [Google Scholar] is re-described. Three higher altitude species are new to science: Liodessus azufralis sp. n., L. quillacinga sp. n. and L. quimbaya sp. n. We also introduce two new subspecies, L. quillacinga cochaensis ssp. n. and L. quillacinga cumbalis ssp. n. We delineate the species using morphological structures such as male genital structure and beetle size, shape and colour pattern. Mitochondrial cox1 sequence data provided an additional character source. All the new species occur on higher altitudes above 2700 m and were collected in shallow, exposed peatland pools and puddles, mostly in Páramo. Liodessus obscurellus (LeConte, 1852), not yet recorded from Colombia, is included into the key due to its presence in nearby Costa Rica and Ecuador. The known distribution and habitat preferences of each species are outlined briefly.     

Field observation of predation on a horsehair worm (Gordioida: Chordodidae) by a diving beetle larva Cybister brevis Aubé (Coleoptera: Dytiscidae)

Diving beetles (Coleoptera: Dytiscidae) are carnivorous in both the larval and adult stages; larvae are exclusively predatory, whereas adults also scavenge for food. They are known to prey on zooplankton, insects, gastropods, fish, amphibians and reptiles. However, there have been no previous reports detailing direct predation on adult Gordioida by Dytiscidae in the field. This study represents the first observation of a diving beetle larva, Cybister brevis Aubé (Coleoptera: Dytiscidae), predating on an adult horsehair worm (Gordioida: Chordodidae). This might be the first report of predation on horsehair worms by insects.     

Papuadessus pakdjoko – a new genus and species of rheobiont diving beetle from New Guinea of potential use for environmental impact assessments (Coleoptera,Dytiscidae)

Papuadessus pakdjoko n.gen., n.sp. is described from New Guinea. This species is well characterised by its coloration and the shape of the male genitalia. It is not yet possible to identify closer relatives of this species based on morphological evidence. The new species is a rheobiont, and only occurs at the edge of medium-sized to large rivers in gravelly and sandy substrates. Sites with mud or other finer substrates were unihabited by P. pakdjoko. It is concluded that this species could, therefore, be a good indicator to use in environmental impact assessments, especially where logging and large scale mining strongly increase the input of fine substrates to rivers.     

Development of microsatellite markers for an extremely limited distributed rare diving beetle species,Acilius kishii,and a widely distributed species,Acilius japonicus (Coleoptera: Dytiscidae)

Acilius kishii Nakane, 1963 (Coleoptera: Dytiscidae) is an endangered diving beetle species distributed in only one location, Lake Yashaga‐Ike, Honshu Island, Japan. Acilius japonicus, which is related to A. kishii, is distributed widely in northern Honshu Island and Hokkaido Island in Japan. In this study, we identified 14 microsatellite loci for A. kishii and A. japonicus, including both polymorphic and monomorphic loci, using the next‐generation sequencing method. We observed that 5 and 10 loci showed polymorphisms in 31 and 32 individuals of A. kishii and A. japonicus, respectively. The observed and expected heterozygosities were 0.00–1.00 and 0.00–0.74, respectively. These microsatellite loci could be useful for future conservation genetic studies, including monitoring of genetic diversity and extinction risk of A. kishii.