Some American Austrolimnius (Coleoptera: Elmidae)

A key is given to the North American species of Austrolimnius, one of which is described as new. A new species from Venezuela is described, and new locality records in North and South America are listed for previously described species.     

Discovery of swimming larvae in Elmidae (Coleoptera: Byrrhoidea)

The aquatic larvae of the family Elmidae (Coleoptera) have been considered unable to swim because they lack swimming setae on their body and legs. We discovered that riffle beetle larvae (Leptelmis gracilis Sharp) are in fact able to swim. After opening the tuft‐like gills on the last abdominal segment they swim by repeatedly bending the abdomen into a U‐shape very quickly and in a wavy manner, while their head and thorax move anteriorly, resulting in a sigmoidal body shape. The flat bodies of L. gracilis larvae could be advantageous for swimming compared to the cylindrical or semicylindrical bodies of larvae in related genera.     

Description of Optioservus gapyeongensis new species and Heterlimnius hasegawai (Nomura) (Coleoptera: Elmidae) new to Korea

A new riffle beetle species Optioservus gapyeongensis n. sp. is described from the adult and larval stages. Heterlimnius hasegawai (Nomura), previously misidentified in Korea as Optioservus (Cyclolimnius) kubotai Nomura or Optioservus variabilis Nomura, is redescribed. The adults and larvae of both species inhabit attached mosses on substrates of clean mountain streams, headwaters or springs. Photographs of dorsal adults and habitats and line drawings of diagnostic characters are provided.     

A Revision of the Limnius perrisi Subspecies Group (Coleoptera: Elmidae) in the Iberian Peninsula

A revision of the Limnius perrisi subspecies group in the Iberian Peninsula is presented. Limnius perrisi subcarinatus (Sharp, 1872) is a new synonym of Limnius perrisi carinatus (Pérez-Arcas, 1865). Morphological variability related to some elytral interstriae corresponds to a geographical gradation. Limnius perrisi is restricted to the headwaters of highslope streams with low levels of dissolved minerals.     

Physical gills in Elmidae (Coleoptera: Byrrhoidea): Structure and evolutionary pattern of plastron in Stenelmis and related genera

Many species within Elmidae (Coleoptera: Byrrhoidea) have plastrons composed of flattened setae. However, some genera display fine plastrons on the epicuticle, called plastron hairs. In Japanese elmids, members of the genera Stenelmis, Ordobrevia, Nomuraelmis and Leptelmis bear ventral plastron hairs. Based on a maximum likelihood tree including most Japanese genera within Elmidae, we found that these genera are monophyletic and that plastron hairs are a derived character in Elmidae. We also found that the genus Graphelmis bears jigsaw puzzle‐like plastron scales with plastron hair‐like projections, and is sister to the group with plastron hairs.     

Hintoniella,a replacement name for the preoccupied generic name Helonastes Hinton, 1968 (Coleoptera: Byrrhoidea: Elmidae)

Abstract

A replacement name, Hintoniella is proposed for the generic name Helonastes Hinton, 1968 in the family Elmidae (Coleoptera: Byrrhoidea).     

Limiting similarity in subterranean ecosystems: a case of niche differentiation in Elmidae (Coleoptera) from epigean and hypogean environments

Hydrobiologia - Environmental pressures in caves can act on species, selecting functional attributes that allow their best performance in such habitats. Caves are simplified habitats, which makes...     

Distribution Patterns and Habitat Characterization of Elmidae and Hydraenidae (Insecta: Coleoptera) in the Weidlingbach Near Vienna,Austria

A total of 870 adult and 831 larval Elmidae and Hydraenidae were caught from September 1995 to September 1996 at the Weidlingbach, a fourth order tributary of the Danube near Vienna, Austria, using a Heß sampler at 14 sampling stations from source to mouth. Elmis maugetii (Latreille ) and Riolus subviolaceus (Müller ) accounted for 66.3% of the total, whereas Hydraena gracilis (Germar ) was the most abundant Hydraenidae species. Based on head width, instars 1–6 were collected in E. maugetii, instars 2–6 in R. subviolaceus and instars 3–6 in Limnius volckmari (Panzer ) and Riolus cupreus (Müller ); from the remaining species, only instars 4–6 were sampled. E. maugetii was most abundant on coarse, moss-covered substrates (median = 22.2 mm) exposed to high water velocity (median = 69.4 cm/s; range = 6.0–117.6 cm/s); the latter was also true for R. subviolaceus although it favoured smaller sediment grain sizes (median = 10.7 mm). Sites exposed to only moderate flow and with abundant filiform algae were preferred by Esolus parallelepipedus (Müller ) and L. volckmari, whereas the Hydraenidae species, Esolus angustatus (Müller ), R. cupreus and Oulimnius tuberculatus (Müller ) were collected mostly at sites with moderate current speed and abundant moss-covered pebbles of various size. Species richness and population density increased from source to mouth. At the spring sampling site Elmidae and Hydraenidae were completely lacking.     

The species of Myochrous Erichson (Coleoptera: Chrysomelidae) occurring in Central America

Myochrous femoralis Jacoby is redescribed and a species from Nicaragua is described as new. A new key is given to the 12 species of Myochrous known from Central America. A list of Jacoby's type-material of this group is included and lectotypes are designated where necessary.     

Three new species of Dalechampia (Euphorbiaceae) from Venezuelan Guayana

Three new species ofDalechampia are described from the Guayanan region of Venezuela.Dalechampia attenuistylus belongs to sectionRhopalostylis and may be most closely related toD. parvibracteata Lanj.Dalechampia megacarpa belongs to sectionDioscoreifoliae, although it is not especially close to any species in the section.Dalechampia papillistigma is also an isolated member of sectionDioscoreifolieae.     

Identification of elmid larvae (Coleoptera: Elmidae) from Sanin District of Honshu,Japan, based on mitochondrial DNA sequences

Larvae of Elmidae from the Sanin District, Honshu, Japan, were classified into 14 types based on morphological features, of which 11 types were unidentified for species. Species or genus of the unidentified types were determined by comparing their mitochondrial cytochrome oxidase subunit I gene sequences with those of identified adult specimens. A new key to species/genera of elmid larvae was proposed.     

Pre-copulatory isolation in sympatric Melolontha species (Coleoptera: Scarabaeidae)

1 The two most abundant cockchafer species in Europe, the forest cockchafer Melolontha hippocastani Fabr. and the European cockchafer Melolontha melolontha L., tend to form calamitous mass breedings with casual reports on sympatric and simultaneous occurrence. 2 Both species are known to use feeding‐induced green leaf volatiles (GLV) as primary attractants (sexual kairomones) for mate finding. The attractiveness of GLV is enhanced by the sex pheromones 1,4‐benzoquinone in M. hippocastani and toluquinone in M. melolontha. Phenol attracts males from both species. All three compounds are present in females of both species. 3 In the present study, it is confirmed that only male M. melolontha perform the typical swarming flight at dusk, as has already been shown for M. hippocastani. Furthermore, whether swarming Melolontha males were cross‐attracted to heterospecific females, and whether males could discriminate olfactorily between conspecific and heterospecific females, was tested in the field. 4 Males of both species preferred females when given the choice between females and males of the other species. However, they preferred conspecific females when females from both species were offered simultaneously. 5 The results suggest that species‐specific pheromone blends contribute to precopulatory reproductive isolation in sympatric populations of M. melolontha and M. hippocastani, but are not mutually exclusive or indispensable prerequisites for mate finding as in other insects.     

Two pselaphine species (Coleoptera: Staphylinidae) new to Korea

Two pselaphine staphylinid species –Stipesa rudis Sharp and Tainochus nitidus Nomura – are identified for the first time in the Korean peninsula.     

Descriptive biogeography of Tomicus (Coleoptera: Scolytidae) species in Spain

Aim, location Tomicus (Coleoptera, Scolytidae) species are some of the principal pests of Eurasian forest and are represented by three coexisting species in Spain, Tomicus piniperda (Linnaeus, 1758), Tomicus destruens (Wollaston, 1865) and Tomicus minor (Harting, 1834). The distribution of two taxa are unknown as they have until recently been considered separate species. Therefore, we model the potential distribution centres and establish the potential distribution limits of Tomicus species in Iberia. We also assess the effectiveness of different models by comparing predicted results with observed data. These results will have application in forest pest management. Methods Molecular and morphological techniques were used to identify species from 254 specimens of 81 plots. For each plot, a Geographical Information System was used to extract a set of 14 environmental (one topographic, six climatic) and biotic variables (seven host tree distributions). General Additive Models and Ecological Niche Factor Analysis models are applied for modelling and predicting the potential distribution of the three especies of Tomicus. Results The results of both modelling methodologies are in agreement. Tomicus destruens is the predominant species in Spain, living in low and hot areas. Tomicus piniperda occurs in lower frequency and prefers wet and cold areas of north‐central Spain. We detected sympatric populations of T. destruens and T. piniperda in Northern coast of Spain, infesting mainly P. pinaster. Tomicus minor is the rarest species, and it occupies a fragmented distribution located in high and wet areas. The remarkable biotic variable is the distribution of P. sylvestris, incorporated into the models of T. destruens and T. piniperda. Main conclusions These results indicate that in wet areas of north‐central Spain where T. piniperda occurs (and possibly the high altitudes of the southern mountains), T. destruens has a climatic distribution limit. In the northern border of this area, both species overlap their distributions and some co‐occurrences were detected. Tomicus minor potentially occurs in high and wet fragmented areas.     

Korean species of the genus Bisnius Stephens (Coleoptera: Staphylinidae)

Two Korean species of the genus Bisnius Stephens are studied. Bisnius macies (Sharp), found along the seashore of some islands, is introduced for the first time in Korea.