Molecular phylogeny of rootworms and related galerucine beetles (Coleoptera: Chrysomelidae)

The Galerucinae (Coleoptera: Chrysomelidae) sensu stricto (true galerucines) comprise a large assemblage of diverse phytophagous beetles containing over 5000 described species. Together with their sister taxon, the flea beetles, which differ from true galerucines by having the hind femora usually modified for jumping, the Galerucinae sensu lato comprises over 13 000 described species and is the largest natural group within the Chrysomelidae. Unlike the flea beetles, for which robust hierarchical classification schemes have not been erected, an existing taxonomic structure exists for the true galerucines, based mostly on the works of the late John Wilcox. In the most recent taxonomic list of the Galerucinae sensu stricto, five tribes were established comprising 29 sections housing 488 genera. The majority of the diversity within these tribes is found within the tribe Luperini, in which two genera, Monolepta and Diabrotica, are known to contain over 500 described species. Here, we extend the work from previous phylogenetic studies of the Galerucinae by analysing four amplicons from three gene regions (18S and 28S rRNA; COI) representing 249 taxa, providing the largest phylogenetic analysis of this taxon to date. Using two seven‐state RNA models, we combine five maximum likelihood models (RNA + DNA for the rRNAs; three separate DNA models for the COI codon positions) for these partitions and analyse the data under likelihood using Bayesian inference. The results of these two analyses are compared with those from equally weighted parsimony. Instead of choosing the results from one optimality criterion over another, either based on statistical support, tree topology or philosophical predisposition, we elect to draw attention to the similar results produced by all three analyses, illustrating the robustness of the data to these different analytical methods. In general, the results from all three analyses are consistent with each other and previous molecular phylogenetic reconstructions for Galerucinae, except that increased taxon sampling for several groups, namely the tribes Hylaspini and Oidini, has improved the phylogenetic position of these taxa. As with previous analyses, under‐sampled taxa, such as the Old World Metacyclini and all sections of the subtribe Luperina, continue to be unstable, with the few taxa representing these groups fluctuating in their positions based on the implemented optimality criterion. Nonetheless, we report here the most comprehensive phylogenetic estimation for the Galerucinae to date.     

Anti-predator defence drives parallel morphological evolution in flea beetles

Complex morphological or functional traits are frequently considered evolutionarily unique and hence useful for taxonomic classification. Flea beetles (Alticinae) are characterized by an extraordinary jumping apparatus in the usually greatly expanded femur of their hind legs that separates them from the related Galerucinae. Here, we examine the evolution of this trait using phylogenetic analysis and a time-calibrated tree from mitochondrial (rrnL and cox1) and nuclear (small subunits and large subunits) genes, as well as morphometrics of femora using elliptic Fourier analysis. The phylogeny strongly supports multiple independent origins of the metafemoral spring and therefore rejects the monophyly of Alticinae, as defined by this trait. Geometric outline analysis of femora shows the great plasticity of this structure and its correlation with the type and diversity of the metafemoral springs. The recognition of convergence in jumping apparatus now resolves the long-standing difficulties of Galerucinae-Alticinae classification, and cautions against the value of trait complexity as a measure of taxonomic significance. The lineage also shows accelerated species diversification rates relative to other leaf beetles, which may be promoted by the same ecological factors that also favour the repeated evolution of jumping as an anti-predation mechanism.     

叶甲科口器比较形态学研究(鞘翅目,叶甲科)

叶甲科成虫为植食性昆虫,是典型的咀嚼式口器。本文对叶甲科3亚科9属9种(Chrysomelinae：Crosita altaica altaica Gebler,Chrysolina exanchalcea (Wiedemann),Humba cyanicollis (Hope);Galerucinae：Galeruca nigrolineata Mannerheim,Gallerucida gloriosa Baly,Atrachya menetriesi(Falermann);Alticinae：Ophrida spectabis(Baly);Podontia lurea (Olivier);Euphitrea micans Baly)的口器进行了比较形态学研究,并对其形态演化进行了讨论。     

跳甲的食性及食性分化

跳甲隶属于鞘翅目叶甲科跳甲亚科,是一类具有重要经济意义的植食性昆虫。本文对跳甲食性及食性分化的研究进展进行了综述,诠释了寄主植物的概念,分析了昆虫食性专化发生的原因。跳甲亚科的寄主植物的范围虽广,但有85%的属为专食性属。一般认为,专食性的跳甲亚科和萤叶甲亚科是由食性较广的叶甲亚科进化而来的,食性分化在其中可能起了重要作用。广食性代价推动了食性分化的发生,广食性代价假说受到越来越多的实验支持。有关食性分化方向的观点倾向于寄主植物转向化学物质相似的植物,表现为寄主转移、寄主扩张和形成寄主型等;食性分化推动了同域物种形成。跳甲食性分化的研究对于丰富研究昆虫与植物相互关系的协同进化理论也有重要作用。     

Inter-generic differences in the metafemoral apodeme of flea beetles (Chrysomelidae: Alticinae)

Abstract. The metafemoral apodeme, an essential element of the unique jumping mechanism in the chrysomelid subfamily Alticinae (flea beetles), was studied in fifty-three Palearctic species of twenty-six genera. Inter-generic differences are noted and these genera separate into seven groups according to their apodeme structure. The significance of the metafemoral apodeme in phylo-genetic relationships at the generic and subfamilial level is discussed.     

The metatibial extensor and flexor tendons in Coleoptera

The metatibiae of genera in several families of Coleoptera with enlarged metafemora are examined, including Chrysomelidae (Alticinae, Galerucinae, Sagrinae), Bruchidae (Pachymerinae, Rhae-binae, Eubaptinae, Bruchinae), Scirtidae and Oedemeridae. There is an evident pattern concerning the relative size of the tibial extensor and flexor tendons that is dependent on the type of hind leg movement of a specific beetle group. Beetle groups that jump (e.g. Alticinae, Scirtidae) always have a greatly enlarged metatibial extensor tendon and associated musculature. However, other groups with swollen metafemora that do not jump have enlarged metatibial flexor tendons with the associated musculature for holding/grasping onto the vegetation (Sagrinae, Bruchidae) or onto the female during copulation (male Oedemera). This indicates a strong functional relationship between Sagrinae and Bruchidae, both with large flexor tendons, and between the Alticinae and Galerucinae, with relatively large extensor tendons; these two cases may also have phylogenetic meaning. This pattern of the metatibial extensor and flexor tendon size related to function is presumably true for at least all other Coleoptera.     

The phylogeny of leaf beetles (Chrysomelidae) inferred from mitochondrial genomes

The high-level classification of Chrysomelidae (leaf beetles) currently recognizes 12 or 13 well-established subfamilies, but the phylogenetic relationships among them remain ambiguous. Full mitochondrial genomes were newly generated for 27 taxa and combined with existing GenBank data to provide a dataset of 108 mitochondrial genomes covering all subfamilies. Phylogenetic analysis under maximum likelihood and Bayesian inference recovered the monophyly of all subfamilies, except that Timarcha was split from Chrysomelinae in some analyses. Three previously recognized major clades of Chrysomelidae were broadly supported: the ‘chrysomeline’ clade consisting of (Chrysomelinae (Galerucinae + Alticinae)); the ‘sagrine’ clade with internal relationships of ((Bruchinae + Sagrinae) + (Criocerinae + Donaciinae)), and the ‘eumolpine’ clade comprising (Spilopyrinae (Cassidinae (Eumolpinae (Cryptocephalinae + Lamprosomatinae)))). Relationships among these clades differed between data treatments and phylogenetic algorithms, and were complicated by two additional deep lineages, Timarcha and Synetinae. Various topological tests favoured the PhyloBayes software as the preferred inference method, resulting in the arrangement of (chrysomelines (eumolpines + sagrines)), with Timarcha placed as sister to the chrysomeline clade and Synetinae as a deep lineage splitting near the base. Whereas mitogenomes provide a solid framework for the phylogeny of Chrysomelidae, the basal relationships do not agree with the topology of existing molecular studies and remain one of the most difficult problems of Chrysomelidae phylogenetics.     

The phylogeny of Galerucinae (Coleoptera: Chrysomelidae) and the performance of mitochondrial genomes in phylogenetic inference compared to nuclear rRNA genes

With efficient sequencing techniques, full mitochondrial genomes are rapidly replacing other widely used markers, such as the nuclear rRNA genes, for phylogenetic analysis but their power to resolve deep levels of the tree remains controversial. We studied phylogenetic relationships of leaf beetles (Chrysomelidae) in the tribes Galerucini and Alticini (root worms and flea beetles) based on full mitochondrial genomes (103 newly sequenced), and compared their performance to the widely sequenced nuclear rRNA genes (full 18S, partial 28S). Our results show that: (i) the mitogenome is phylogenetically informative from subtribe to family level, and the per‐nucleotide contribution to nodal support is higher than that of rRNA genes, (ii) the Galerucini and Alticini are reciprocally monophyletic sister groups, if the classification is adjusted to accommodate several ‘problematic genera’ that do not fit the dichotomy of lineages based on the presence (Alticini) or absence (Galerucini) of the jumping apparatus, and (iii) the phylogenetic results suggest a new classification system of Galerucini with eight subtribes: Oidina, Galerucina, Hylaspina, Metacyclina, Luperina, Aulacophorina, Diabroticina and Monoleptina.     

Revisiting the phylogeny of microsporidia

Canonical microsporidians are a group of obligate intracellular parasites of a wide range of hosts comprising ~1,300 species of >220 genera. Microsporidians are related to fungi, and many characterised and uncharacterized groups closely related to them have been discovered recently, filling the knowledge gaps between them. These groups assigned to the superphylum Opisthosporidia have provided several important insights into the evolution of diverse intracellular parasitic lineages within the tree of eukaryotes. The most studied among opisthosporidians, canonical microsporidians, were known to science more than 160 years ago, however, the classification of canonical Microsporidia has been challenging due to common morphological homoplasy, and accelerated evolutionary rates. Instead of morphological characters, ssrRNA sequences have been used as the primary data for the classification of canonical microsporidians. Previous studies have produced a useful backbone of the microsporidian phylogeny, but provided only some nodal support, causing some confusion. Here, we reconstructed phylogenetic trees of canonical microsporidians using Bayesian and Maximum Likelihood inferences. We included rRNA sequences of 126 described/named genera, by far the broadest taxon coverage to date. Overall, our trees show similar topology and recovered four of the five main clades demonstrated in previous studies (Clades 1, 3, 4 and 5). Family level clades were well resolved within each major clade, but many were discordant with the recently revised classification. Therefore, revision and some reshuffling, especially within and between Clades 1 and 3 are required. We also reconstructed phylogenetic trees of Opisthosporidia to better integrate the evolutionary history of canonical microsporidians in a broader context. We discuss several traits shared only by canonical microsporidians that may have contributed to their striking ecological success in diverse metazoans. More targeted studies on the neglected host groups will be of value for a better understanding of the evolutionary history of these interesting intracellular parasites.     

Phylogeny of Pilobolaceae

The three genera traditionally classified as Pilobolaceae have been identified on the basis of morphological characteristics. In the absence of distinctive morphological differences phylogenetic techniques have proven to be superior for developing phylogenies. Molecular techniques have been used primarily for studies of higher fungi; there are few investigations of the Zygomycota using genetic sequences for classification. DNA sequences coding for three regions of rRNA were used to investigate phylogenetic relationships of the three genera traditionally considered within the Pilobolaceae. Evidence indicates that Pilaira should be removed from Pilobolaceae and the family redescribed. Sporangiospore size is the morphological characteristic that most closely correlates with rDNA clades of phylogenetic trees. This study demonstrates that traditional morphological characteristics alone are not adequate to differentiate species of Pilobolus.     

Outer membrane efflux protein (OMEP) is a suitable molecular marker for resolving the phylogeny and taxonomic status of closely related cyanobacteria

Taxonomy of Cyanobacteria, the oldest phototrophic prokaryotes, is problematic for many years due to their simple morphology, high variability and adaptability to diverse ecological niches. After introduction of the polyphasic approach, which is based on the combination of several criteria (molecular sequencing, morphological and ecological), the whole classification system of these organisms is subject to reorganization. The aim of this study was to evaluate whether the outer membrane efflux protein (OMEP) sequences can be used as a molecular marker for resolving the phylogeny and taxonomic status of closely related cyanobacteria. We have performed phylogenetic analyses based on the amino acid sequences of the OMEP and the DNA sequences of the 16S rRNA gene from 86 cyanobacterial species/strains with completely sequenced genomes. Phylogenetic trees based on the OMEP showed that most of the cyanobacterial species/strains belonging to different genera are clustered in separate clades supported by high bootstrap values. Comparing the OMEP trees with the 16S rDNA tree clearly showed that the OMEP is more suitable marker in resolving phylogenetic relationships within Cyanobacteria at generic and species level.     

Phylogenies from genetic and morphological characters do not support a revision of Gigasporaceae (Glomeromycota) into four families and five genera

The family Gigasporaceae consisted of the two genera Gigaspora and Scutellospora when first erected. In a recent revision of this classification, Scutellospora was divided into three families and four genera based on two main lines of evidence: (1) phylogenetic patterns of coevolving small and large rRNA genes and (2) morphology of spore germination shields. The rRNA trees were assumed to accurately reflect species evolution, and shield characters were selected because they correlated with gene trees. These characters then were used selectively to support gene trees and validate the classification. To test this new classification, a phylogenetic tree was reconstructed from concatenated 25S rRNA and β-tubulin gene sequences using 35% of known species in Gigasporaceae. A tree also was reconstructed from 23 morphological characters represented in 71% of known species. Results from both datasets showed that the revised classification was untenable. The classification also failed to accurately represent sister group relationships amongst higher taxa. Only two clades were fully resolved and congruent among datasets: Gigaspora and Racocetra (a clade consisting of species with spores having one inner germinal wall). Other clades were unresolved, which was attributed in part to undersampling of species. Topology of the morphology-based phylogeny was incongruent with gene evolution. Five shield characters were reduced to three, of which two were phylogenetically uninformative because they were homoplastic. Therefore, most taxa erected in the new classification are rejected. The classification is revised to restore the family Gigasporaceae, within which are the three genera Gigaspora, Racocetra, and Scutellospora. This classification does not reflect strict topology of either gene or morphological evolution. Further revisions must await sampling of additional characters and taxa to better ascertain congruence between datasets and infer a more accurate phylogeny of this important group of fungi.     

入侵害虫甘薯凹胫跳甲的鉴定及线粒体基因组分析

【目的】基于形态学鉴定和分子生物学技术确认甘薯凹胫跳甲Chaetocnema confinis是否入侵中国大陆,测定甘薯凹胫跳甲线粒体基因组序列,分析基因组结构及其系统发育关系。【方法】应用显微镜观察从广东不同地点采集的甘薯凹胫跳甲成虫的形态特征,并扩增cox1基因DNA序列进行分子鉴定;利用Illumina MiSeq测序平台对甘薯凹胫跳甲线粒体基因组进行测序、拼装、注释和特征分析;基于亲缘关系相近种属的线粒体基因组序列进行共线性分析和构建系统发育树,分析基因重排和系统发育关系。【结果】形态和分子鉴定结果表明大陆甘薯上发现的跳甲为甘薯凹胫跳甲。甘薯凹胫跳甲线粒体基因组序列大小为15 685 bp,包括有13个蛋白质编码基因、2个rRNA基因、22个tRNA基因和1个非编码控制区;这37个基因之间排列紧凑,间隔总长度101 bp,排列顺序与模式昆虫Drosophila yakuba线粒体基因排列顺序相同。甘薯凹胫跳甲线粒体基因组A+T含量为77.3%,具有明显的AT偏向性。13个蛋白质编码基因的起始密码子均为ATN。在22个tRNA基因中除trnS1的DHU臂缺失,trnD, trnG, trnN和trnT的二级结构中缺少TψC环外,其余17个都能形成典型的三叶草式二级结构,另trnK的反密码子突变为UUU,trnS1的反密码子突变为UCU。甘薯凹胫跳甲的控制区片段长度仅有60 bp,是目前已报道的昆虫线粒体基因组中最短的控制区。基于线粒体基因组的系统发育分析表明,甘薯凹胫跳甲与跳甲亚科(Alticinae)黄曲条跳甲Phyllotreta striolata亲缘关系最近。【结论】甘薯凹胫跳甲已经入侵到中国大陆。本研究获得了甘薯凹胫跳甲的线粒体基因组序列,为防控甘薯凹胫跳甲和分析叶甲科(Chrysomelidae)各种属间的系统发育关系奠定了基础。     

Phylogenetic relationships of Polyporus and morphologically allied genera

Polyporus accommodates morphologically heterogeneous species and is divided into six infrageneric groups based on macromorphological characters. On the other hand allied genera have macro- and microscopic characters similar to those of Polyporus. The phylogenetic relationships of Polyporus and allied genera were established from sequences of RNA polymerase II second largest subunit (RPB2), nuclear ribosomal large subunit (nucLSU) and mitochondrial ATPase subunit 6 (ATP6). The molecular phylogenetic trees confirmed that Polyporus is a polyphyletic genus and recognized six major clades (1-6) containing species of Polyporus and several allied genera. Among the clades one contained three infrageneric groups of Polyporus and two allied genera, Datronia and Pseudofavolus while one other contained group Polyporellus and Lentinus. Five of the six major clades contained species belonging to a single infrageneric group, Favolus, Melanopus, Polyporellus or Polyporus. This suggests that morphological characters used to define these groups have phylogenetic significance and reveals the need for a taxonomic revision of Polyporus and its allied genera.     

Convergent evolution of cucurbitacin feeding in spatially isolated rootworm taxa (Coleoptera: Chrysomelidae; Galerucinae,Luperini)

Historically, chemical ecologists assumed that cucurbitacin feeding and sequestration in rootworm leaf beetles is a remnant of an ancient association between the Luperini (Coleoptera: Chrysomelidae; Galerucinae) and Cucurbitaceae (ancestral host hypothesis). Under this premise, rootworms that do not develop on cucurbits but undergo pharmacophagous forays for cucurbitacins are thought to do so to supplement novel host diets that lack these bitter compounds. The ancestral host hypothesis is supported from studies of pyrrolizidine alkaloid pharmacophagy in Lepidoptera but has not been subjected to phylogenetic analysis within the Luperini. New evidence that this feeding behavior is better correlated with an adult affinity for pollen than with larval host offers the possibility that Old and New World rootworm species with an affinity for cucurbitacins converged on this behavior through apomorphic taste receptor modifications (loose receptor hypothesis). Here we test the monophyly of cucurbitacin feeding within the Luperini by using nuclear and mitochondrial sequence data to infer phylogenetic relationships among 49 taxa representing tribes of the Galerucinae and subtribes of the Luperini. The resulting phylogenetic hypothesis is mostly concordant with existing tribal and subtribal delineations within the Subfamily Galerucinae sensu stricto (Galerucinae not including the flea beetles). The establishment of ancestry among the subtribes of the Luperini refutes the monophyly of cucurbitacin feeding and cucurbit specialization, with the New World Diabroticina being paraphyletic to the Old World Aulacophorina and cosmopolitan Luperina. These data unambiguously support the convergent evolution of cucurbitacin feeding in rootworms and are inconsistent with the ancestral host hypothesis.     

Phylogenetic Classification at Generic Level in the Absence of Distinct Phylogenetic Patterns of Phenotypical Variation: A Case Study in Graphidaceae (Ascomycota)

Molecular phylogenies often reveal that taxa circumscribed by phenotypical characters are not monophyletic. While re-examination of phenotypical characters often identifies the presence of characters characterizing clades, there is a growing number of studies that fail to identify diagnostic characters, especially in organismal groups lacking complex morphologies. Taxonomists then can either merge the groups or split taxa into smaller entities. Due to the nature of binomial nomenclature, this decision is of special importance at the generic level. Here we propose a new approach to choose among classification alternatives using a combination of morphology-based phylogenetic binning and a multiresponse permutation procedure to test for morphological differences among clades. We illustrate the use of this method in the tribe Thelotremateae focusing on the genus Chapsa, a group of lichenized fungi in which our phylogenetic estimate is in conflict with traditional classification and the morphological and chemical characters do not show a clear phylogenetic pattern. We generated 75 new DNA sequences of mitochondrial SSU rDNA, nuclear LSU rDNA and the protein-coding RPB2. This data set was used to infer phylogenetic estimates using maximum likelihood and Bayesian approaches. The genus Chapsa was found to be polyphyletic, forming four well-supported clades, three of which clustering into one unsupported clade, and the other, supported clade forming two supported subclades. While these clades cannot be readily separated morphologically, the combined binning/multiresponse permutation procedure showed that accepting the four clades as different genera each reflects the phenotypical pattern significantly better than accepting two genera (or five genera if splitting the first clade). Another species within the Thelotremateae, Thelotrema petractoides, a unique taxon with carbonized excipulum resembling Schizotrema, was shown to fall outside Thelotrema. Consequently, the new genera Astrochapsa, Crutarndina, Pseudochapsa, and Pseudotopeliopsis are described here and 39 new combinations are proposed.     

Evolutionary constraints in hind wing shape in Chinese dung beetles (Coleoptera: Scarabaeinae)

This study examines the evolution hindwing shape in Chinese dung beetle species using morphometric and phylogenetic analyses. Previous studies have analyzed the evolution of wing shape within a single or very few species, or by comparing only a few wing traits. No study has analyzed wing shape evolution of a large number of species, or quantitatively compared morphological variation of wings with proposed phylogenetic relationships. This study examines the morphological variation of hindwings based on 19 landmarks, 119 morphological characters, and 81 beetle species. Only one most parsimonious tree (MPT) was found based on 119 wing and body characters. To better understand the possible role of the hindwing in the evolution of Scarabaeinae, additional phylogenetic analyses were proposed based on the only body features (106 characters, wing characters excluded). Two MPT were found based on 106 body characters, and five nodes were collapsed in a strict consensus. There was a strong correlation between the morphometric tree and all phylogenetic trees (r>0.5). Reconstructions of the ancestral wing forms suggest that Scarabaeinae hindwing morphology has not changed substantially over time, but the morphological changes that do occur are focused at the base of the wing. These results suggest that flight has been important since the origin of Scarabaeinae, and that variation in hindwing morphology has been limited by functional constraints. Comparison of metric disparity values and relative evolutionary sequences among Scarabaeinae tribes suggest that the primitive dung beetles had relatively diverse hindwing morphologies, while advanced dung beetles have relatively similar wing morphologies. The strong correlation between the morphometric tree and phylogenetic trees suggest that hindwing features reflect the evolution of whole body morphology and that wing characters are suitable for the phylogenetic analyses. By integrating morphometric and cladistic approaches, this paper sheds new light on the evolution of dung beetle hind wings.     

Phylogenetic classification of the Drosophilidae Rondani (Diptera): the role of morphology in the postgenomic era

Molecular sequences now overwhelm morphology in phylogenetic inference. Nonetheless, most molecular studies are conducted on a limited number of taxa, as DNA rarely can be analysed from old museum types or fossils. During the last 20 years, more than 150 molecular studies have challenged the current phylogenetic classification of the family Drosophilidae Rondani based on morphological characters. Most studies concerned a single genus, Drosophila Fallén, and included only few representative species from 17 out of the 78 genera of the family. Therefore, these molecular studies were unable to provide an alternative classification scheme. A supermatrix analysis of seven nuclear and one mitochondrial genes (8248 bp) for 33 genera was conducted using outgroups from one calyptrate and four ephydroid families. The Bayesian phylogeny was consistent with previous molecular studies including whole genome sequences and divided the Drosophilidae into four monophyletic clades. Morphological characters, mostly male genitalia, then were compared thoroughly between the four clades and homologous character states were identified. These states were then checked for 70 genera and a revised phylogenetic, family‐group classification for the Drosophilidae is proposed. Two genera –Cladochaeta Coquillett and Diathoneura Duda – of the tribe Cladochaetini Grimaldi are transferred to the family Ephydridae. The Drosophilidae is divided into two subfamilies: Steganinae Hendel (30 genera) and Drosophilinae Rondani (43 genera). A further two genera, Apacrochaeta Duda and Sphyrnoceps de Meijere, are incertae sedis, and Palmophila Grimaldi, is synonymized with Drosophila syn.n. The Drosophilinae is subdivided into two tribes: the re‐elevated Colocasiomyini Okada (nine genera) and Drosophilini Okada. The paraphyly of the genus Drosophila was not resolved to avoid affecting the binomina of important laboratory model species; however, its subgeneric classification was revised in light of molecular and morphological data. Three subgenera, namely Chusqueophila Brncic, Phloridosa Sturtevant and Psilodorha Okada, were synonymized with the subgenus Drosophila (Drosophila) Fallén syns.n. Among the 45 species groups and 5 species complexes of Drosophila (Drosophila), 22 groups and 1 complex were transferred to the subgenus Drosophila (Siphlodora) Patterson & Mainland and 6 groups, 2 species subgroups and 3 complexes are considered incertae sedis within the genus Drosophila. Different morphological characters provide different signals at different phylogenetic scales: thoracic characters (wing venation and presternal shape) discriminate families; grasping and erection‐related characters discriminate subfamilies to tribes; whereas phallic paraphyses, i.e. auxiliary intromittent organs, discriminate genera and Drosophila subgenera. The study shows the necessity of analysing morphological characters within a molecular phylogenetic framework to translate molecular phylogenies into taxonomically‐comprehensive classifications.     

Convergent evolution of chemical defence in Galerucine larvae

Selection pressure by natural enemies on phytophagous insect larvae is intense and has frequently triggered the evolution of chemical defence as an effective counterstrategy. In the chrysomelid subfamily Galerucinae, glandular structures and defensive fluids have been described for the tribe Sermylini Wilcox, 1965. Previous morphological and ultrastructural studies raised doubts that these defensive devices in Sermylini can be traced back to a common origin. The taxonomy of the Galerucinae cannot clear these doubts because the phylogeny of this taxon is a matter of current debate. We therefore investigated the phylogeny of the Galerucinae based on approximately 1740 bp of the mitochondrial 12S and 16S rRNA and the nuclear elongation factor 1 alpha genes. Our data support the hypothesized close relationship between the subfamilies Galerucinae and Alticinae, yet, by contrast to other recent analyses, the two groups are mostly resolved as monophyletic sister groups or, in some analyses, with the Galerucinae nested paraphyletically within the Alticinae. Within the subfamily Galerucinae, only the tribe Galerucini formed a monophyletic taxon, except for one species, Cerochroa brachialis Stal, 1858. In none of our analyses were the Sermylini recovered as a monophyletic tribe. However, our data support monophyly of each of the three groups within the Sermylini that have morphologically distinguishable larval defensive openings. We conclude that the defensive structures in larvae of Sermylini have no common origin, but evolved independently. Our data suggest that the tremendous selection pressure by natural enemies led to the recurrent evolution of similar chemical defensive devices in Sermylini larvae.  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 93 , 165–175.