Association of aphid life stages using DNA sequences: A case study of tribe Eriosomatini (Hemiptera: Aphididae: Pemphiginae)

Association of aphid life stages based on a portion of COI sequence was applied in Eriosomatini. Three aphid specimens, nos. 17496, 19265a, and 19265b collected on Gramineae roots all clustered with Tetraneura chinensis Mordvilko with strong support. The average pairwise p‐distance among the four taxa was 0.001 (range, 0.000–0.002), and that among all the ingroup taxa was 0.065 (range, 0.000–0.141). This indicated that nos. 17496 and 19265 b were the secondary‐host morphs of T. chinensis. In this paper the secondary host morph of T. chinensis is described for the first time. With the identification of more species' secondary‐host morphs, aphids identification based on this morph will be made easily.     

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.     

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.     

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.     

Dytiscus latissimus and D. circumcinctus (Coleoptera,Dytiscidae) larvae as predators on three case-making caddis larvae

The predacious behaviour of Dytiscus circumcinctus and D. latissimus larvae was studied experimentally. When offered different prey simultaneously, D. latissimus larvae preferred cased caddis larvae relative to mayfly nymphs and isopods, whereas in D. circumcinctus the preference order was reversed. Notonectid nymphs and tadpoles were consumed in higher numbers by D. circumcinctus than by D. latissimus larvae. D. circumcinctus larvae and instar III larvae of D. latissimus most frequently captured caddis larvae through the case wall, whereas the instar I and II larvae of D. latissimus normally attacked the thorax of the exposed larva from above the front opening of the case. Limnephilus borealis, L. nigriceps and L. rhombicus caddis larvae differed in case structure, and they were all successfully captured by D. latissimus and D. circumcinctus instar II and III larvae. Neither capture success nor ingestion efficiency varied significantly between the two Dytiscus species or between different prey species. Instar II and III D. circumcinctus larvae had shorter reaction times than those of D. latissimus. The larger L. borealis and L. rhombicus larvae were preferred by the two last Dytiscus larval instars, and the handling time of these two prey was longer than that of L. nigriceps larvae.     

Predaceous diving beetle, Dytiscus sharpi sharpi (Coleoptera: Dytiscidae) larvae avoid cannibalism by recognizing prey

Larvae of diving beetles such as the various Dytiscus species (Coleoptera: Dytiscidae) are carnivorous and usually prey on other aquatic animals. Cannibalism among larvae of Dytiscus sharpi sharpi (Wehncke) was observed to begin when they were starved for more than two days under artificial breeding conditions. However, the 2-day starved larvae did not show cannibalism in the presence of intact, motionless, frozen tadpoles, or frozen shrimps. The beetle larvae attacked and captured intact tadpoles faster (15 sec) than other motionless and frozen tadpoles (120 sec), indicating that prey movement was an important factor in stimulating feeding behavior in larvae. Prey density does not have an effect on larval cannibalism. In cases in which preys are present at lower densities than that of larvae, a group of beetle larvae frequently fed on single prey. This feeding behavior, therefore, provides direct evidence of self-other recognition at the species level. Using two traps in one aquarium that allows the larvae to detect only prey smell, one containing tadpoles and another empty, the beetle larvae were attracted to the trap with tadpoles at high frequency, but not to the empty trap. In another experiment, the beetle larvae were not attracted to the trap containing a beetle larva. These results suggest that the larvae of D. sharpi sharpi are capable of recognizing prey scent, which enables the promotion of foraging behavior and the prevention of cannibalism.     

Phylogeny and diversification of diving beetles (Coleoptera: Dytiscidae)

Dytiscidae is the most diverse family of beetles in which both adults and larvae are aquatic, with examples of extreme morphological and ecological adaptations. Despite continuous attention from systematists and ecologists, existing phylogenetic hypotheses remain unsatisfactory because of limited taxon sampling or low node support. Here we provide a phylogenetic tree inferred from four gene fragments (cox1, rrnL, H3 and SSU, ≈ 4000 aligned base pairs), including 222 species in 116 of 174 known genera and 25 of 26 tribes. We aligned ribosomal genes prior to tree building with parsimony and Bayesian methods using three approaches: progressive pair‐wise alignment with refinement, progressive alignment modeling the evolution of indels, and deletion of hypervariable sites. Results were generally congruent across alignment and tree inference methods. Basal relationships were not well defined, although we identified 28 well supported lineages corresponding to recognized tribes or groups of genera, among which the most prominent novel results were the polyphyly of Dytiscinae; the grouping of Pachydrini with Bidessini, Peschetius with Methlini and Coptotomus within Copelatinae; the monophyly of all Australian Hydroporini (Necterosoma group), and their relationship with the Graptodytes and Deronectes groups plus Hygrotini. We found support for a clade formed by Hydroporinae plus Laccophilini, and their sister relationship with Cybistrini and Copelatinae. The tree provided a framework for the analysis of species diversification in Dytiscidae. We found a positive correlation between the number of species in a lineage and the age of the crown group as estimated through a molecular clock approach, but the correlation with the stem age was non‐significant. Imbalances between sister clades were significant for several nodes, but the residuals of the regression of species numbers with the crown age of the group identified only Bidessini and the Coptotomus + Agaporomorphus clade as lineages with, respectively, above and below expected levels of species diversity. © The Willi Hennig Society 2008.     

A highly modified stygobiont diving beetle of the genus Copelatus (Coleoptera,Dytiscidae): taxonomy and cladistic analysis based on mitochondrial DNA sequences

Abstract. We report the discovery of a new species of Copelatus that is morphologically highly modified for life in groundwater. Copelatus abditus sp.n. was collected from a 4 m deep bore in central Australia. It was placed in Copelatinae based on morphological evidence. This is the first known stygobiont diving beetle that does not belong to the subfamily Hydroporinae. Sequences from the mitochondrial DNA cytochrome oxidase 1, 16S rRNA, tRNAL and NADH dehydrogenase subunit 1 genes suggest that the species belongs to the subgenus Papuadytes, the morphological apomorphies of which are reduced in the new groundwater species. Copelatus (Papuadytes) abditus very much resembles other world stygobiont dytiscids, which all belong to the subfamily Hydroporinae. We suggest that this striking convergence is due to similar selective pressures imposed on all groundwater beetles. We suggest a scenario in which species from temporary habitats evade drought by entering the hyporheic zone, and may be driven to a subterranean existence by desertification of their ancestral habitats, as can be observed in Australia.     

Status of Japanese Dytiscus species (Coleoptera: Dytiscidae) based on mitochondrial DNA sequence data

We sequenced 628 base pairs of the mitochondrial cytochrome‐c oxidase subunit 1 (cox1) gene to investigate the genetic differentiation among Japanese Dytiscus diving beetles (Coleoptera: Dytiscidae). Dytiscus beetles are a charismatic part of the fauna of lakes, ponds and swamps. Three species are known from Japan: D. dauricus Gebler, 1832; D. marginalis czerskii Zeitzev * , 1953; and D. sharpi Wehncke, 1875. Adults of D. sharpi collected in Chiba and Ishikawa Prefectures were morphologically highly similar, but here we found that they differed by 20 cox1 base pairs (3.18%). Our results imply that conservation strategies especially for Japanese D. sharpi sharpi and D. sharpi validus Régimbart, 1899 might need to be adjusted to address the presence of two evolutionarily significant units.     

Revision of the Neotropical genus Leptochromus Motschulsky (Coleoptera: Scydmaenidae)

Abstract The Neotropical genus Leptochromus Motschulsky (Coleoptera: Scydmaenidae) is revised, and a phylogenetic analysis of Clidicini is presented. Leptochromus includes five species distributed from Veracruz, Mexico to Manaus, Brazil. Leptochromus fulvescens Motschulsky, L. mexicanus (Sharp) and L. agilis (Sharp) are considered valid species. Leptochromus bicolor O'Keefe, sp.n. from Veracruz, Mexico and L . palaeomexicanus O'Keefe, sp.n. from Miocene amber from Chiapas are described. Male genitalia and antennae are illustrated for each of the extant species. Female genitalia, mouthparts and other morphological features are illustrated for the type species L. fulvescens. For the phylogenetic analysis of Clidicini, Palaeoleptochromus O'Keefe was placed as the sister taxon to Leptochromus , and Papusus Casey was placed as the sister taxon to Leptochromus  + Palaeoleptochromus . Papusus is elevated from synonomy with Leptochromus and the biogeography of Clidicini is discussed.     

铜绿丽金龟的室内人工饲养

对室内饲养铜绿丽金龟Anomala corpulenta Motschulsky的方法和主要影响因子进行了研究。结果表明：室内饲养的铜绿丽金龟种群完成一个世代平均为272.3天,3龄幼虫期比田间种群缩短了103.8天。在饲养过程中,幼虫的生长容易受到土壤湿度、食料、病原微生物的影响。卵的孵化率为86.0%,1龄、2龄和3龄幼虫的存活率分别为82.0%、76.0%和60.0%。10和15日龄幼虫在含有马铃薯的土壤中饲养14天后的死亡率分别为8.8%±16%和4.0%±1.6%,明显低于初孵幼虫及5日龄幼虫的死亡率,可以作为生物测定的最佳供试幼虫。紫外线处理的壤土和沙壤土中铜绿丽金龟幼虫可以正常生长,死亡率较低。     

Retinal ultrastructure may mediate polarization sensitivity in larvae of the Sunburst diving beetle, Thermonectus marmoratus (Coleoptera: Dytiscidae)

A number of invertebrates are known to be sensitive to the polarization of light and use this trait in orientation, communication, or prey detection. In these animals polarization sensitivity tends to originate in rhabdomeric photoreceptors that are more or less uniformly straight and parallel. Typically, polarization sensitivity is based on paired sets of photoreceptors with orthogonal orientation of their rhabdomeres. Sunburst diving beetle larvae are active swimmers and highly visual hunters which could potentially profit from polarization sensitivity. These larvae, like those of most Dytiscids, have a cluster of six lens eyes or stemmata (designated E1 through E6) on each side of the head capsule. We examined the ultrastructure of the photoreceptor cells of the principal eyes (E1 and E2) of first instar larvae to determine whether their rhabdomeric organization could support polarization sensitivity. A detailed electron microscopical study shows that the proximal retinas of E1 and E2 are in fact composed of photoreceptors with predominantly parallel microvilli and that neighboring rhabdomeres are oriented approximately perpendicularly to one another. A similar organization is observed in the medial retina of E1, but not in the distal retinas of E1&2. Our findings suggest that T. marmoratus larvae might be able to analyze polarized light. If so, this could be used by freshly hatched larvae to find water or within the water to break the camouflage of common prey items such as mosquito larvae. Physiological and behavioral tests are planned to determine whether larvae of T. marmoratus can actually detect and exploit polarization signals.     

Mass breeding larvae of the critically endangered diving beetles Dytiscus sharpi sharpi and Dytiscus sharpi validus (Coleoptera: Dytiscidae)

For conservation purposes, and to supply critically endangered insects for laboratory use, a system for artificial breeding is crucial. However, in the case of carnivorous insects such as diving beetles, the larvae must be isolated because they are cannibalistic. We developed a method for mass breeding the larvae of two diving beetles, Dytiscus sharpi sharpi (Wehncke) and Dytiscus sharpi validus (Régimbart) (Coleoptera: Dytiscidae), which are designated critically endangered species in Japan. Ten to twenty larvae were raised in a small tank (35 cm × 25 cm × 10 cm; water depth 7 cm) with Rana ornativentris (Werner) tadpoles as prey. At low prey density, ~80 % of the larvae were cannibalized. At moderate prey density, 50–60 % were cannibalized. However, at high prey density, <3 % were cannibalized. Well-fed mass-bred adults were larger than individually bred and field-collected adults. This mass breeding method can be used for the conservation and breeding of these rare diving beetles in a manageable number of aquaria.     

Avoidance of unpalatable prey by predaceous diving beetle larvae: The role of hunger level and experience (Coleoptera: Dytiscidae)

The effects of hunger and experience on the avoidance of unpalatable prey were examined. Larvae of the predaceous diving beetle,Dytiscus verticalis, after feeding on one of two feeding regimes, were offered palatable and unpalatable prey during a series of trials. Consumption of palatable prey (calf heart) was not affected by hunger or experience. Avoidance of unpalatable prey (tails of the red-spotted newtNotophthalmus viridescens) decreased with increased hunger, with hungrier predators sampling unpalatable prey more often. Although the overall level of avoidance varied across trials, the degree of difference in avoidance between predators at different hunger levels remained relatively constant across trials. Beetle larvae responded to an increase in their feeding regime within 36 h (after two trials), by becoming more selective. In a separate experiment, hunger level affected the number of beetle larvae that seized unpalatable newt tails, but experience did not.     

Structure in temperate predaceous diving beetle communities (Coleoptera: Dytiscidae)

Collection records of adult dytiscid beetles (Coleoptera, Dytiscidae) from 312 sites within the province of Alberta, Canada, were analyzed for patterns of similarity in species distribution. Sites compared on the basis of species occurrence (Jaccard coefficient of similarity and group average cluster analysis) separated into 12 principal clusters, interpreted as communities. However, cluster inclusion occurred at very low levels of similarity and 30% of sites were unclustered outliers. Ecological charade us tics of sites that were recognized as varying between dusters were salinity, productivity, stability, water temperature, substrate type, flow and vegetation. An index relating these qualitatively defined variables to species numbers is presented. An analysis of co-occurrence patterns of species was conducted as an alternative approach to definition of multispecies associations. Each possible combination of co-occurrence between pairs of species occurring in more than 5 collections each was tested for significance (p = 0.005) by means of Yates corrected χ² tests. Results of tests were expressed in binary terms, blank – no significance, x - significant. Species were then clustered on the basis of patterns of significant co-occurrences as above. This analysis was used as the basis for ordination of species in a symmetrical matrix with species ordered so as to maximize density of points of significant co-occurrence (x) around the principal diagonal. Areas in the matrix showing high densities of co-occurrence were interpreted as representing communities. The cluster analysis of species produced a better cluster pattern than obtained for sites but while generally similar, the species clustering pattern was less fine. The principal species groups consisted of those of saline water, alpine/subalpine lotic sites, other lotic habitats, and lentic habitats with two subgroups, species in forest areas and grassland species. The ordination, while reflecting this grouping of species, demonstrated that each group graded into others through loss of certain species and acquisition of others and thus showed the continuum nature of these communities. Restricting ordination to congeneric species indicated that these do not usually show identical patterns of co-occurrence but neither are patterns coincident with mutual exclusion. Within genera, considerable overlap in occurrence between species is the norm but species tend to occupy slightly different positions relative to one another along qualitatively defined ecological gradients. Relative position of species in these ordinations shows good correlation with patterns of geographical distribution lending support to the interpretation of ordination patterns reflecting relative ecological segregation. The dytiscid beetle fauna of north temperate regions is especially rich. Also, the large number of significant co-occurrences observed between species shows that species packing in many habitats of this region is dense. It is speculated that this species richness is possible because of the seasonality of habitats at these latitudes which reduces competition and predation from other groups and produces seasonal pulses of high productivity permitting a species rich fauna to develop because of abundant resources. It is likely that factors other than interspecific competition for resources are important in shaping dytiscid communities in habitats with strong nutrient pulses.     

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.