A molecular phylogeny of chafers revisits the polyphyly of Tanyproctini (Scarabaeidae,Melolonthinae)

Tanyproctini (Melolonthinae) is a large group of chafers within the pleurostict Scarabaeidae that shows an enormous morphological diversity and variation. However, their morphology based definition appears to be mainly based on presumably plesiomorphic characters. Here, we investigate the phylogeny of this interesting lineage with a three‐gene data set using partial gene sequences of 28S rRNA, cytochrome c oxidase I (cox1) and 16S rRNA (rrnL). Our data set comprised 191 species of all major lineages of pleurostict scarabs. Combined analyses of the 2,070 base pairs alignment with maximum‐likelihood and Bayesian tree inference always recovered Tanyproctini to be highly polyphyletic. Tests of an alternative topology with constrained monophyly of Tanyproctini using CONSEL and IQ‐TREE were not found to be more likely than the unconstrained tree topology. Instead, Tanyproctini was split into six independent lineages under the current taxon sampling that were scattered throughout diverse parts of the pleurostict tree. The fact that numerous smaller chafer lineages exist beside several evolutionary successful and large lineages, highlights the complexity of the pleurosticts’ evolutionary history. The resulting tree topologies imply the need for a thorough revision of tribal classification within Melolonthinae lineages to accommodate the polyphyly of Tanyproctini. However, a revision of classification would be premature due to low support of most relevant branches, instable tree topologies among different tree searches, and due to a still very incomplete representation of Tanyproctini lineages.     

The phylogeny of Sericini and their position within the Scarabaeidae based on morphological characters (Coleoptera: Scarabaeidae)

Abstract. To reconstruct the phylogeny of the Sericini and their systematic position among the scarabaeid beetles, cladistic analyses were performed using 107 morphological characters from the adults and larvae of forty‐nine extant scarabaeid genera. Taxa represent most ‘traditional’ subfamilies of coprophagous and phytophagous Scarabaeidae, with emphasis on the Sericini and other melolonthine lineages. Several poorly studied exoskeletal features have been examined, including the elytral base, posterior wing venation, mouth parts, endosternites, coxal articulation, and genitalia. The results of the analysis strongly support the monophyly of the ‘orphnine group’ + ‘melolonthine group’ including phytophagous scarabs such as Dynastinae, Hopliinae, Melolonthinae, Rutelinae, and Cetoniinae. This clade was identified as the sister group to the ‘dung beetle line’ represented by Aphodius + Copris. The ‘melolonthine group’ is comprised in the strict consensus tree by two major clades and two minor lineages, with the included taxa of Euchirinae, Rutelinae, and Dynastinae nested together in one of the major clades (‘melolonthine group I’). Melolonthini, Cetoniinae, and Rutelinae are strongly supported, whereas Melolonthinae and Pachydemini appear to be paraphyletic. Sericini + Ablaberini were identified to be sister taxa nested within the second major melolonthine clade (‘melolonthine group II’). As this clade is distributed primarily in the southern continents, one could assume that Sericini + Ablaberini are derived from a southern lineage. Plausibly, ancestors of Sericini + Ablaberini and Athlia were separated by a vicariance event, such as the separation of the African plate from the rest of Gondwana, whereas Sericini and Ablaberini probably diversified during the early Tertiary, with dispersal of some basal Sericini to South America.     

The phylogeny of monkey beetles based on mitochondrial and ribosomal RNA genes (Coleoptera: Scarabaeidae: Hopliini)

Monkey beetles (Hopliini) are a large clade of flower and leaf feeding species within the Scarabaeidae (chafers) with greatest diversity in southern Africa. Their internal relationships and sister group affinities have not been studied with DNA methods. We used partial gene sequences for 28S rRNA, cytochrome oxidase I (cox1) and 16S rRNA (rrnL) for 158 species, representing most recognized subfamilies of Scarabaeidae, including 46 species of Hopliini. Combined analyses using maximum likelihood and Bayesian inference under the two preferred alignment parameters recovered the Hopliini as monophyletic. Hopliines were inserted at the base of a clade of Cetoniinae+Rutelinae+Dynastinae, being either recovered as their immediate sister group, or as part of an expanded set of basal branches that also includes the tribe Macrodactylini which has been classified as part of the Melolonthinae (may chafers). At the level of subtribes, we found Hopliina paraphyletic with respect to Pachycnemina which also includes the monophyletic clade of Heterochelina and Gymnolomina. Trait mapping under parsimony on the preferred tree resulted in inferences of three independent origins of sexual dimorphism, which coincided with shifts to 'flower-embedding' pollination. In contrast, night active taxa, which are general phyllophages as other pleurostict chafers, never show clear sexual dimorphism. South African lineages include several deep-branching lineages. The exceptional morphological and phylogenetic diversity of the South African fauna may therefore be due to their antiquity, in addition to sexual selection in the day-active lineages. Phylogenetic studies of the endemic South African plant radiations have demonstrated the repeated evolutionary shift to beetle pollination, but it remains to be investigated if this is driven by the hopliine pollinators present in the bioregion or by a propensity of the local plant lineages favoring this pollination syndrome.     

Structure and localization of sensilla on antennae of caddisflies (Insecta: Trichoptera)

Structure of antenna segments and ultrastructure of antennal sensillae in representatives of 28 caddisfly families from both modern suborders were studied by electron and light microscopy methods. On Trichoptera antennae, 16 types of sensillae were found, some of them being described for the first time. Morphological peculiarities of cuticular ultrastructures on the antennal surface demonstrate essential differences in structure both at the family level and at the lower taxonomic levels. Specialized sensory fields structurally different from the remaining antennal surface were revealed on antennal flagellae in representatives of the Phryganeina suborder. A new classification of sensillae based on the structure of their cuticular section is proposed.     

东北大黑鳃金龟嗅感器超微结构

利用扫描电镜和透射电镜对东北大黑鳃金龟Holotrichia diomphalia成虫触角嗅感器进行超微结构研究。结果表明： 其嗅感器集中于触角鳃片上,着生在表皮内陷形成的凹腔里。嗅感器包括锥形感器和板形感器两种,锥形感器根据锥体形状的差异可分为4种类型,板形感器根据盘体形状的不同可分为5种类型。嗅感器表皮为单壁,壁上具有微孔和孔道微管。嗅感器内神经元的数目并不一致,1～3个不等。雄性触角鳃片的长度长于雌性触角鳃片,并且雄性触角嗅感器的总数远远多于雌性,其中雄性板形感器的数目与雌性差异不大,但雄性锥形感器的数目却远远的多于雌性,几乎是雌性的9倍。由此推测锥形感器是感受性信息素的感器,而板形感器用于感受植物气味。     

Morphology and Distribution of Sensilla on the Antennae of Hylamorpha elegans Burmeister (Coleoptera: Scarabaeidae)

Considering that sensilla constitute important functional elements of sensory systems in insects, the aim of this study was to determine the type and distribution of sensilla in the antennae of Hylamorpha elegans Burmeister examined by scanning electron microscopy. Hylamorpha elegans antennae are lamellate and consist of the scape, pedicel, and flagellum. The antennal club of this beetle consists of three terminal plates: proximal, middle, and distal lamellae. Four types of sensilla were observed in the lamellae from both sexes: sensilla trichoidea, chaetica, coeloconica, and placodea. Antennal length was larger in males than in females, and significant sexual variation in the number of sensilla placodea and sensilla coeloconica was observed.     

Antennal sensilla of grasshoppers (Orthoptera: Acrididae) in relation to food preferences and habits

The external structure, i.e. number and distribution of sensillae on male and female antennae of 12 species of grasshoppers belonging to Pamphaginae, Catantopinae, Oedipodinae and Gomphocerinae in the grasslands of Inner Mongolia was investigated using scanning electron microscopy. Five major types of antennal sensillae were detected - trichoid, long basiconic, short basiconic, slender and short basiconic, and coeloconic sensillae. Total number of antennal sensillae varied among different sexes, subfamilies, feeding groups, life forms and eco-forms. Males showed significantly more sensillae than females, due to presence of more short basiconic and coeloconic sensillae. Species under Catantopinae showed more long basiconic sensillae than the others. The Oedipodinae had the highest number of slender and short basiconic sensillae and coeloconic sensillae, followed by Catantopinae and Gomphocerinae; while Pamphaginae had the fewest. The total number of sensillae showed the same trend for these two types amongst the subfamilies as well, species which prefer habits on the ground possessed fewer antennal sensillae than species which prefer to stay on plants. The maximal number of antennal sensillae were observed in hygrophytous species,Chorthippus albomarginatus, in the 12 grasshopper species investigated, although the data is not statistically significant. The general trend which emerged was that species feeding on grass possessed more antennal sensillae, particularly coeloconic sensillae, compared to other feeding group species.     

草地贪夜蛾成虫触角感器超微结构观察

[目的]草地贪夜蛾是一种严重危害农业生产的迁飞性害虫,本研究旨在了解草地贪夜蛾成虫触角感器的类型、超微结构和分布.[方法]采用扫描电镜对其雌雄成虫触角感器类型及分布进行观察.[结果]草地贪夜蛾雌雄成虫触角由柄节、梗节及鞭节3部分组成,雄蛾触角稍长于雌蛾,且触角表面覆有大量鳞片.共观察到7种类型的感受器,分别为B?hm氏...     

苹毛丽金龟触角嗅感器超微结构

利用扫描电镜和透射电镜对苹毛丽金龟Proagopertha lucidula (Faldermann)雌雄成虫触角嗅感器超微结构特征进行研究。结果表明:嗅感器集中于触角鳃片上,分布在触角鳃片表皮内陷形成的凹腔里,有5种感器,以板状感器为主,以外还有锥状感器、腔状感器、腔锥状感器和毛状感器。板状感器根据盘体形状的不同可分为4种类型,锥状感器根据锥体形状的差异可分为2种类型,腔锥状感器根据形状分为2种类型。嗅感器表皮有微孔和孔道微管。嗅感器内神经元的数目并不一致,1～2个不等。雄虫鳃片嗅感器总数显著多于雌性,是雌虫嗅感器总数1.8倍。其中雄性锥状感器的数目是雌性2倍,雌虫腔锥状感器数量是雄虫的4倍,雄虫板状感器数量是雌虫的2倍,雌雄腔状感器的数目无显著性差异。     

Molecular phylogeny of the fungus gnat family Mycetophilidae (Diptera,Mycetophiliformia)

Abstract A molecular phylogeny of the fungus gnat family Mycetophilidae based on the nuclear 18S, 28S, and the mitochondrial 16S rRNA genes is presented. The total alignment included 58 taxa and 1704 bp. The family was recovered as monophyletic in parsimony and Bayesian analyses. In the Bayesian analysis, Mycetophilinae and its two tribes, Mycetophilini and Exechiini, were monophyletic with good statistical support. The subfamily Mycomyinae was found consistently in a sister‐group relationship to Mycetophilinae. Gnoristinae was rendered paraphyletic, subtending Mycomyinae and Mycetophilinae. Within Gnoristinae, the genera Coelosia Winnertz, Boletina Staeger, Gnoriste Meigen group with Docosia Winnertz, usually considered to be a member of Leiinae. No support was found for the monophyly of the subfamilies Sciophilinae and Leiinae.     

Mitogenome of Coprophanaeus ensifer and phylogenetic analysis of the Scarabaeidae family (Coleoptera)

Several studies about the phylogenetic relationships of the Scarabaeinae subfamily (Coleoptera: Scarabaeidae) have been performed, but some phylogenetic uncertainties persist including the relationship and monophyly of different tribes and some genera. The aim of this study was to characterize the mitogenome of Coprophanaeus ensifer in order to establish its position within the Scarabaeidae family and to contribute to the resolution of some phylogenetic uncertainties. The mitogenome was sequenced on the Illumina HiSeq 4000, assembled using the Mitobim software and annotated in MITOS WebServer. The phylogenetic trees were reconstructed by Bayesian inference. The C. ensifer mitogenome is a molecule of 14,964 bp that contains the number and organization of the genes similar to those of most Coleoptera species. Phylogenetic reconstruction suggests monophyly of the tribe Phanaeini and supports the hypothesis that Coprini is a sister group of Phanaeini. The results also revealed the position of the tribe Oniticellini which is grouped with Onthophagini and Onitini. The geographic distribution of these species that form the most ancestral clade suggests with Scarabaeinae originated in Africa. Keywords: Dung beetle, mitochondrial genome, phylogenomics     

On the evolution of adult head structures and the phylogeny of Hydraenidae (Coleoptera, Staphyliniformia)

External and internal head structures of adults of Orchymontiinae, Prosthetopinae, Hydraeninae and Ochthebiinae were studied and those of Ochthebius semisericeus and Limnebius truncatellus are described in detail. The results are evaluated with respect to their relevance for a reconstruction of hydraenid phylogeny and also compared with structural features found in adults of other staphyliniform families. The monophyly of Hydraenidae is supported by the presence of a plate‐like, trilobed premento‐hypopharyngeal extension, an unusual origin of m. tentoriohypopharyngalis, dorsal tentorial arms firmly fused with the head capsule, modified basal antennomeres, and palpigers connected by a transverse sclerotized bar. Orchymontiinae are monophyletic and the basal sister group of the remaining Hydraenidae. The presence of a ventral transverse genal bulge and of a pubescent antennal club with more than two antennomeres (reversal in some prosthetopines: e.g. Mesoceration abstrictum) are possible apomorphies of Hydraenidae excluding Orchymontiinae. Prosthetopinae are probably monophyletic and the sister group of Ochthebiinae + Hydraeninae. The latter clade is characterized by a distinct cupula formed by antennomere VI, a loose five‐segmented pubescent antennal club, and a modified antennal musculature. The presence of an unusual tentorio‐pharyngeal dilator is a shared derived feature of Ochthebiinae and the genus Davidraena. The monophyly of Ochthebiinae was confirmed and Ochtheosus is the sister group of the remaining ochthebiine genera, which are characterized by a perforated wall‐like structure formed by the posterior tentorial arms. The absence of this tentorial modification and the fimbriate galea are plesiomorphies retained in Ochtheosus. Calobius differs strongly from other subgenera of Ochthebius and a generic status may be appropriate. The monophyly of Hydraeninae is not supported. Hydraena was confirmed as a clade and Laeliaena and Limnebius are sister groups. The latter genus is characterized by several autapomorphies. The basal position of Orchymontiinae and Prosthetopinae suggests a Gondwanan origin of Hydraenidae and a primary preference for life in running water. Important evolutionary changes of head structures are complex transformations of the antennae and related structures. Yet, the use of the antennae as accessory breathing organs is not a groundplan feature of the family. The results of this study strengthen the case of staphylinoid affinities of Hydraenidae.     

Structure of the mushroom bodies in Scarabaeoidea (Coleoptera): 2. Phytophagous Scarabaeidae and general discussion

The mushroom body structure is progressively more complicated within the superfamily Scarabaeoidea. In the basal families and coprophagous Scarabaeidae, the calyx region is asymmetrical and poorly developed but reaches the maximal degree of development in the phytophagous Scarabaeidae of the subfamilies Melolonthinae and Cetoniinae. These Scarabaeidae have two separate calyces; moreover, some species have additional regions of glomerular neuropile. The processes of different Kenyon cell types segregate into special subdivisions of vertical and medial lobes. It is assumed that a progressive development of the mushroom body in phytophagous Scarabaeidae is associated with the need to integrate olfactory and visual information.     

The disunity of "Mysidacea" (Crustacea)

New studies on malacostracan relationships have drawn attention to issues concerning monophyly of the order Mysidacea, manifested in recent crustacean classifications that treat the taxon as two separate orders, Lophogastrida and Mysida. We present molecular phylogenies of these orders based on complete sequences of nuclear small-subunit ribosomal DNA (18S rRNA), and morphological evidence is used to revise the classification of the order Mysida to better reflect evolutionary history. A secondary structure model for 18S rRNA was constructed and used to assign putative stem and loop regions to two groups of partitions for phylogenetic analyses. Phylogenies were estimated by maximum-likelihood, Bayesian inference, and maximum-parsimony. The analyses gave strong support for three independently derived lineages, represented by three monophyletic groups, Lophogastrida, Stygiomysida, and Mysida. The family Petalophthalmidae is considered as sister group to the family Mysidae, and Boreomysinae and Rhopalophthalminae are the most early derived of the Mysidae. The tribes contained in the current classification of the subfamily Mysinae are not well-supported by either molecular data or morphology.     

A Molecular Phylogeny of the Tiger Beetles (Cicindelidae): Congruence of Mitochondrial and Nuclear rDNA Data Sets

As a basis for comparative studies in the family Cicindelidae (tiger beetles), a phylogenetic hypothesis for major groups was established based on molecular data, focusing on the taxa of the New World. Two markers, mitochondrial 16S rRNA and nuclear 18S rRNA, were sequenced for a total of 912 nucleotides and 30 taxa. All Cicindelidae were inferred to be a monophyletic group by the presence of a segment in the 5′ region of the 18S rDNA which is predicted to fold into a single stem-loop structure not present in the outgroup. The total number of variable and potentially informative positions was smaller in the 18S data set, but their higher internal consistency resulted in a strong phylogenetic signal. Inferred relationships were stable over a wide range of alignment parameters, but the inclusion of alignment-sensitive positions and presumptive gap characters added substantially to the resolution and overall support of the tree. Both data sets were in general congruence. The combined evidence suggests that relationships in Cicindelidae as currently recognized have to be reconsidered. No convincing evidence could be found for the traditional subdivision into two subfamilies, Cicindelinae and Collyrinae. The latter is embedded within the Cicindelinae and clearly not the sister to all other cicindelids. Most of the current tribes and subtribes, particularly in the Megacephalini, are paraphyletic groups, whereas monophyly of the large tribe Cicindelini is well supported by the molecular data.     

桉小卷蛾触角感器的超微结构

[目的] 桉小卷蛾是桉树、番石榴等林木和果树的一种重要害虫。为确定桉小卷蛾成虫触角上的感器对寻找生存环境及对外界环境的各种刺激所起的作用,研究了桉小卷蛾触角感器的种类、形态和分布。[方法] 利用扫描电镜对桉小卷蛾成虫触角感器进行了详细观察和研究。[结果] 桉小卷蛾雌、雄蛾触角由柄节、梗节和鞭节组成,触角的外侧面覆盖有鳞片;雄性触角略短于雌虫,且鞭节近1/4处有一凹陷。共发现7种感器,即鳞形感器、毛形感器、锥形感器、腔锥形感器、耳形感器、刺形感器和Böhm氏鬃毛,其中以毛形感器数量最多。[结论] 桉小卷蛾雌雄成虫触角的感器种类、分布、数量有一定的规律但又有差异。建议应用气相-触角电位联用技术GC-EAD和触角电位EGA等技术进一步解析触角感器的功能。     

First phylogeny of predatory flower flies (Diptera, Syrphidae, Syrphinae) using mitochondrial COI and nuclear 28S rRNA genes: conflict and congruence with the current tribal classification

The family Syrphidae (Diptera) is traditionally divided into three subfamilies. The aim of this study was to address the monophyly of the tribes within the subfamily Syrphinae (virtually all with predaceous habits), as well as the phylogenetic placement of particular genera using molecular characters. Sequence data from the mitochondrial protein-coding gene cytochrome c oxidase subunit I ( COI ) and the nuclear 28S ribosomal RNA gene of 98 Syrphinae taxa were analyzed using optimization alignment to explore phylogenetic relationships among included taxa. Volucella pellucens was used as outgroup, and representatives of the tribe Pipizini (Eristalinae), with similar larval feeding mode, were also included. Congruence of our results with current tribal classification of Syrphinae is discussed. Our results include the tribe Toxomerini resolved as monophyletic but placed in a clade with genera Ocyptamus and Eosalpingogaster . Some genera traditionally placed into Syrphini were resolved outside of this tribe, as the sister groups to other tribes or genera. The tribe Bacchini was resolved into several different clades. We recovered Paragini as a monophyletic group, and sister group of the genus Allobaccha . The present results highlight the need of a reclassification of Syrphinae.
© The Willi Hennig Society 2008.     

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.     

松突圆蚧雄成虫触角感器的扫描电镜观察

松突圆蚧(Hemiberlesia pitysophila Takagi)是我国南方重要的外来林业害虫。本研究利用扫描电镜对该蚧雄成虫的触角形态和感器进行了观察。结果表明:松突圆蚧雄成虫触角呈线状,由柄节、梗节和鞭节组成,共10节。触角感器共有5种,分别为Bhm氏鬃毛、毛形感器、乳头形感器、锥形感器、火柴形感器,其中,火柴形感器为首次在松突圆蚧雄成虫触角上发现并描述。不同感器在触角各节的数量和分布各不相同,其中,毛形感器数量最多,分布最广,乳头形感器次之,火柴形感器最少。此外,根据感器的分布、形态特征,结合已有的文献描述,推测了感器可能的功能。