The adipokinetic hormones of Odonata: a phylogenetic approach

Adipokinetic neuropeptides from the corpora cardiaca of the major families of all three suborders of the Odonata were identified by one or more of the following methods: (1) Isolation of the peptides from a methanolic extract of the corpora cardiaca by liquid chromatography, peak monitoring by fluorescence of the Trp residue and comparison of the retention time with those of known synthetic peptides of Odonata. (2) Hyperlipaemic bioassays of the HPLC-generated fractions either in Locusta migratoria or, in a few cases, in Anax imperator or Orthetrum julia. (3) Sequencing of the isolated, bioactive HPLAC fraction by Edman degradation. (4) Mass spectrometric measurement of the isolated, bioactive fraction. Sequence assignment revealed that the investigated Odonata species always contain only one adipokinetic peptide. This is always an octapeptide. The suborder Zygoptera contains the peptide code-named Psein-AKH, the Anisozygoptera and the families Aeshnidae, Cordulegastridae and Macromiidae of the Anisoptera contain Anaim-AKH, whereas Gomphidae, Corduliidae (with the exception of Syncordulia gracilis) and Libellulidae contain Libau-AKH; one species of Libellulidae has Erysi-AKH, a very conservative modification of Libau-AKH (one point mutation). When these structural data are interpreted in conjunction with existing phylogenies of Odonata, they support the following: (1) Zygoptera are monophyletic and not paraphyletic. (2) Anisozygoptera and Anisoptera are sister groups and contain the ancestral Anaim-AKH which is independently and convergently mutated to Libau-AKH in Gomphidae and Libellulidae. (3) The Corduliidae are of special interest. Only Corduliidae sensu stricto appear to contain Libau-AKH, other species placed into this family by most authorities contain the ancestral Anaim-AKH. Possibly, assignments of AKHs can untangle the paraphyly of this family.     

Phylogenetic analysis of higher-level relationships of Odonata

Abstract. This is the most comprehensive analysis of higher‐level relationships in Odonata conducted thus far. The analysis was based on a detailed study of the skeletal morphology and wing venation of adults, complemented with a few larval characters, resulting in 122 phylogenetically informative characters. Eighty‐five genera from forty‐five currently recognized families and subfamilies were examined. In most cases, several species were chosen to serve as exemplars for a given genus. The seven fossil outgroup taxa included were exemplar genera from five successively more distant odonatoid orders and suborders: Tarsophlebiidae (the closest sister group of Odonata, previously placed as a family within ‘Anisozygoptera’), Archizygoptera, Protanisoptera, Protodonata and Geroptera. Parsimony analysis of the data, in which characters were treated both under equal weights and implied weighting, produced cladograms that were highly congruent, and in spite of considerable homoplasy in the odonate data, many groupings in the most parsimonious cladograms were well supported in all analyses, as indicated by Bremer support. The analyses supported the monophyly of both Anisoptera and Zygoptera, contrary to the well known hypothesis of zygopteran paraphyly. Within Zygoptera, two large sister clades were indicated, one comprised of the classical (Selysian) Calopterygoidea, except that Amphipterygidae, which have traditionally been placed as a calopterygoid family, nested within the other large zygopteran clade comprised of Fraser's ‘Lestinoidea’ plus ‘Coenagrionoidea’ (both of which were shown to be paraphyletic as currently defined). Philoganga alone appeared as the sister group to the rest of the Zygoptera in unweighted cladograms, whereas Philoganga + Diphlebia comprised the sister group to the remaining Zygoptera in all weighted cladograms. ‘Anisozygoptera’ was confirmed as a paraphyletic assemblage that forms a ‘grade’ towards the true Anisoptera, with Epiophlebia as the most basal taxon. Within Anisoptera, Petaluridae appeared as the sister group to other dragonflies.     

Phylogenetic analysis of the insect order Odonata using 28S and 16S rDNA sequences: a comparison between data sets with different evolutionary rates

Molecular phylogenetic analyses were conducted for the insect order Odonata with a focus on testing the effectiveness of a slowly evolving gene to resolve deep branching and also to examine: (i) the monophyly of damselflies (the suborder Zygoptera); and (ii) the phylogenetic position of the relict dragonfly Epiophlebia superstes. Two independent molecular sources were used to reconstruct phylogeny: the 16S rRNA gene on the mitochondrial genome and the 28S rRNA gene on the nuclear genome. A comparison of the sequences showed that the obtained 28S rDNA sequences have evolved at a much slower rate than the 16S rDNA, and that the former is better than the latter for resolving deep branching in the Odonata. Both molecular sources indicated that the Zygoptera are paraphyletic, and when a reasonable weighting for among‐site rate variation was enforced for the 16S rDNA data set, E. superstes was placed between the two remaining major suborders, namely, Zygoptera and Anisoptera (dragonflies). Character reconstruction analysis suggests that multiple hits at the rapidly evolving sites in the 16S rDNA degenerated the phylogenetic signals of the data set.     

A molecular phylogeny of the Odonata (Insecta)

Abstract. We estimated the phylogeny of the order Odonata, based on sequences of the nuclear ribosomal genes 5.8 S, 18S, and ITS1 and 2. An 18S‐only analysis resolved deep relationships well: the order Odonata, as well as suborders Zygoptera and Epiprocta (Anisoptera + Epiophlebia), emerged as monophyletic. Some other deep clades resolved well, but support for more recently diverged clades was generally weak. A second, simultaneous, analysis of the 5.8S and 18S genes with the intergenic spacers ITS1 and 2 resolved some recent branches better, but appeared less reliable for deep clades with, for example, suborder Anisoptera emerging as paraphyletic and Epiophlebia superstes recovered as an Anisopteran, embedded within aeshnoid‐like anisopterans and sister to the cordulegastrids. Most existing family levels in the Anisoptera were confirmed as monophyletic clades in both analyses. However, within the corduliids that form a major monophyletic clade with the Libellulidae, several subclades were recovered, of which at least Macromiidae and Oxygastridae are accepted at the family level. In the Zygoptera, the situation is complex. The lestid‐like family groups (here called Lestomorpha) emerged as sister taxon to all other zygopterans, with Hemiphlebia sister to all other lestomorphs. Platystictidae formed a second monophylum, subordinated to lestomorphs. At the next level, some traditional clades were confirmed, but the tropical families Megapodagrionidae and Amphipterygidae were recovered as strongly polyphyletic, and tended to nest within the clade Caloptera, rendering it polyphyletic. Platycnemididae were also non‐monophyletic, with several representatives of uncertain placement. Coenagrionids were diphyletic. True Platycnemididae and non‐American Protoneurids are closely related, but their relationship to the other zygopterans remains obscure and needs more study. New World protoneurids appeared relatively unrelated to old world + Australian protoneurids. Several recent taxonomic changes at the genus level, based on morphology, were confirmed, but other morphology‐based taxonomies have misclassified taxa considered currently as Megapodagrionidae, Platycnemididae and Amphipterygidae and have underestimated the number of family‐level clades.     

Coding characters from different life stages for phylogenetic reconstruction: a case study on dragonfly adults and larvae,including a description of the larval head anatomy of Epiophlebia superstes (Odonata: Epiophlebiidae)

The exclusive use of characters coding for specific life stages may bias tree reconstruction. If characters from several life stages are coded, the type of coding becomes important. Here, we simulate the influence on tree reconstruction of morphological characters of Odonata larvae incorporated into a data matrix based on the adult body under different coding schemes. For testing purposes, our analysis is focused on a well‐supported hypothesis: the relationships of the suborders Zygoptera, ‘Anisozygoptera’, and Anisoptera. We studied the cephalic morphology of Epiophlebia, a key taxon among Odonata, and compared it with representatives of Zygoptera and Anisoptera in order to complement the data matrix. Odonate larvae are characterized by a peculiar morphology, such as the specific head form, mouthpart configuration, ridge configuration, cephalic musculature, and leg and gill morphology. Four coding strategies were used to incorporate the larval data: artificial coding (AC), treating larvae as independent terminal taxa; non‐multistate coding (NMC), preferring the adult life stage; multistate coding (MC); and coding larval and adult characters separately (SC) within the same taxon. As expected, larvae are ‘monophyletic’ in the AC strategy, but with anisopteran and zygopteran larvae as sister groups. Excluding larvae in the NMC approach leads to strong support for both monophyletic Odonata and Epiprocta, whereas MC erodes phylogenetic signal completely. This is an obvious result of the larval morphology leading to many multistate characters. SC results in the strongest support for Odonata, and Epiprocta receives the same support as with NMC. Our results show the deleterious effects of larval morphology on tree reconstruction when multistate coding is applied. Coding larval characters separately is still the best approach in a phylogenetic framework. © 2015 The Linnean Society of London     

The sense of smell in Odonata: An electrophysiological screening

Volatile chemicals mediate a great range of intra- and interspecific signalling and information in insects. Olfaction has been widely investigated mostly in Neoptera while the knowledge of this sense in most basal insects such as Paleoptera (Odonata and Ephemeroptera) is still poor. In the present study we show the results of an electrophysiological screening on two model species, Libellula depressa (Libellulidae) and Ischnura elegans (Coenagrionidae), representatives of the two Odonata suborders Anisoptera and Zygoptera, with the aim to deep the knowledge on the sense of smell of this insect order. The antennal olfactory sensory neurons (OSNs) of these two species responded to the same 22 compounds (out of 48 chemicals belonging to different functional groups) encompassing mostly amines, carboxylic acids or aldehydes and belonging to green leaf volatiles, vertebrate related volatiles and volatiles emitted by standing waters bacteria. The properties of Odonata OSNs are very similar to those of ionotropic receptors (IRs) expressing OSNs in other insects.     

Wing length allometry in Odonata: differences between families in relation to migratory behaviour

In insects, wing shape and body size are correlated with several aspects of behaviour, and the optimal morphology of wings is a trade-off between a number of functional demands in relation to behaviour (e.g. foraging, migration and sexual display). Dragonflies are spectacularly skilful flyers and present a range of different wing shapes, but to date, no detailed studies have been conducted in this group on wing length allometry in relation to body size. In this paper, we use published data on body length and wing length in all European and North American dragonflies to investigate differences in wing length allometries among Odonata taxa (suborders and families) and to relate these to behavioural patterns. We found different wing allometries between Zygoptera and Anisoptera, which are probably related to the flight mode and wing form of the two suborders. Among the Anisoptera, the Libellulidae showed a distinct wing length allometry from all other anisopteran families and migrants differed from non-migrant species. The first dichotomy is likely to reflect the adaptation of wing morphology of Libellulidae to sit-and-wait behaviour and to brief foraging flights (most species of this family are perchers) with respect to all other families, members of which are typically flyers. The second dichotomy reflects the trend of migrating species to have relatively longer wings than non-migrating members of the same family. Finally, wing length allometry differed among all the zygopteran families analysed, and this pattern suggested that each family evolved a particular wing morphology in response to peculiarities in behaviour, habitat and flight mode.     

Insect predation on pike fry

Laboratory tests evaluated the predatory impact of the macroinvertebrates Erythromma najas larvae (Odonata, Zygoptera: Coenagrionidae), Notonecta glauca (Heteroptera: Notonectidae), Ilyocoris cimicoides (Heteroptera: Naucoridae), Libellula depressa larvae (Odonata, Anisoptera: Libellulidae), Dytiscus marginalis larvae (Coleoptera: Dytiscidae) and Anax imperator larvae (Odonata, Anisoptera: Aeshnidae) on 3-, 12-, 21- and 30-day-old pike fry Esox lucius . All these insect predators captured and ate pike fry during the test, although the numbers killed varied among species. Dytiscus marginalis, Anax imperator and Notonecta glauca were the most Voracious predators.     

基于线粒体ND1和16S rRNA基因序列探讨中国蝴蝶12科的系统发育关系(鳞翅目: 双孔次亚目: 蝶类)

对中国12科共32种代表蝶类的ND1基因和16S rRNA 基因进行了序列测定（包括新测30种ND1基因和9种16S rRNA基因）和比较分析, 同时采用邻接法、最大似然法和贝叶斯法构建了12科蝶类的系统发育树, 探讨了其高级分类群的系统发育关系。序列分析的结果显示: 经比对处理后的两个基因总长度为869 bp, 其中保守位点373个, 可变位点496个, 简约信息位点375个; A+T的平均含量为80.2％, 明显高于C+G的平均含量19.8％。分子系统树表明: 蛱蝶科不是单系群; 珍蝶类、斑蝶类和喙蝶类位于蛱蝶科内; 粉蝶科和凤蝶科具有共同祖先。据此建议: 绢蝶科应归入凤蝶科; 蚬蝶科归入灰蝶科; 珍蝶类、斑蝶类和喙蝶类作为蛱蝶科中的亚科, 眼蝶类从蛱蝶科中分离出来独立成科。另外, 环蝶类的系统分类地位还有待于进一步研究。     

Molecular evolution of the mitochondrial 12S rRNA in Ungulata (mammalia)

The complete 12S rRNA gene has been sequenced in 4 Ungulata (hoofed eutherians) and 1 marsupial and compared to 38 available mammalian sequences in order to investigate the molecular evolution of the mitochondrial small-subunit ribosomal RNA molecule. Ungulata were represented by one artiodactyl (the collared peccary, Tayassu tajacu, suborder Suiformes), two perissodactyls (the Grevy's zebra, Equus grevyi, suborder Hippomorpha; the white rhinoceros, Ceratotherium simum, suborder Ceratomorpha), and one hyracoid (the tree hyrax, Dendrohyrax dorsalis). The fifth species was a marsupial, the eastern gray kangaroo (Macropus giganteus). Several transition/transversion biases characterized the pattern of changes between mammalian 12S rRNA molecules. A bias toward transitions was found among 12S rRNA sequences of Ungulata, illustrating the general bias exhibited by ribosomal and protein-encoding genes of the mitochondrial genome. The derivation of a mammalian 12S rRNA secondary structure model from the comparison of 43 eutherian and marsupial sequences evidenced a pronounced bias against transversions in stems. Moreover, transversional compensatory changes were rare events within double-stranded regions of the ribosomal RNA. Evolutionary characteristics of the 12S rRNA were compared with those of the nuclear 18S and 28S rRNAs. From a phylogenetic point of view, transitions, transversions and indels in stems as well as transversional and indels events in loops gave congruent results for comparisons within orders. Some compensatory changes in double-stranded regions and some indels in single-stranded regions also constituted diagnostic events. The 12S rRNA molecule confirmed the monophyly of infraorder Pecora and order Cetacea and demonstrated the monophyly of suborder Suiformes. However, the monophyly of the suborder Ruminantia was not supported, and the branching pattern between Cetacea and the artiodactyl suborders Ruminantia and Suiformes was not established. The monophyly of the order Perissodactyla was evidenced, but the relationships between Artiodactyla, Cetacea, and Perissodactyla remained unresolved. Nevertheless, we found no support for a Perissodactyla + Hyracoidea clade, neither with distance approach, nor with parsimony reconstruction. The 12S rRNA was useful to solve intraordinal relationships among Ungulata, but it seemed to harbor too few informative positions to decipher the bushlike radiation of some Ungulata orders, an event which has most probably occurred in a short span of time between 55 and 70 MYA. Correspondence to: E. Douzery     

蜻蜓目高级阶元系统发育关系研究进展

综述了对蜻蜓目系统发育的研究。对一些规模较大较全面的研究结果做了描述,并对其进行比较;对最近的基于分子的和基于形态的研究的共同点做了总结,其共同支持的观点包括:束翅亚目处于分支的基部为一并系类群,差翅亚目与间翅亚目关系较近。     

Molecules, morphology and fossils: a comprehensive approach to odonate phylogeny and the evolution of the odonate wing

We undertook a comprehensive morphological and molecular phylogenetic analysis of dragonfly phylogeny, examining both extant and fossil lineages in simultaneous analyses. The legitimacy of higher‐level family groups and the phylogenetic relationship between families were tested. Thirteen families were supported as monophyletic (Aeshnidae, Calopterygidae, Chlorocyphidae, Euphaeidae, Gomphidae, Isostictidae, Lestidae, Libellulidae, Petaluridae, Platystictidae, Polythoridae, Pseudostigmatidae and Synthemistidae) and eight as non‐monophyletic (Amphipterygidae, Coenagrionidae, Corduliidae, Megapodagrionidae, Protoneuridae and Synlestidae), although Perilestidae and Platycnemididae were recovered as monophyletic under Bayesian analyses. Nine families were represented by one species, thus monophyly was not tested (Epiophlebiidae, Austropetaliidae, Chlorogomphidae, Cordulegastridae, Macromiidae, Chorismagrionidae, Diphlebiidae, Lestoideidae and Pseudolestidae). Epiprocta and Zygoptera were recovered as monophyletic. Ditaxinerua is supported as the sister lineage to Odonata, Epiophlebiidae and the lestid‐like damselflies are sister to the Epiprocta and Zygoptera, respectively. Austropetaliidae + Aeshnidae is the sister lineage to the remaining Anisoptera. Tarsophlebia's placement as sister to Epiprocta or as sister to Epiprocta + Zygoptera was not resolved. Refinements are made to the current classification. Fossil taxa did not seem to provide signals crucial to recovering a robust phylogeny, but were critical to understanding the evolution of key morphological features associated with flight. Characters associated with wing structure were optimized revealing two wing character complexes: the pterostigma–nodal brace complex and the costal wing base & costal–ScP junction complex. In turn, these two complexes appear to be associated; the pterostigma–nodal brace complex allowing for further modification of the wing characters comprised within the costal wing base & costal–ScP junction complex leading the modern odonate wing. © The Willi Hennig Society 2008.     

Phylogenetic reconstruction of the wolf spiders (Araneae: Lycosidae) using sequences from the 12S rRNA, 28S rRNA, and NADH1 genes: implications for classification, biogeography, and the evolution of web building behavior

Current knowledge of the evolutionary relationships amongst the wolf spiders (Araneae: Lycosidae) is based on assessment of morphological similarity or phylogenetic analysis of a small number of taxa. In order to enhance the current understanding of lycosid relationships, phylogenies of 70 lycosid species were reconstructed by parsimony and Bayesian methods using three molecular markers; the mitochondrial genes 12S rRNA, NADH1, and the nuclear gene 28S rRNA. The resultant trees from the mitochondrial markers were used to assess the current taxonomic status of the Lycosidae and to assess the evolutionary history of sheet-web construction in the group. The results suggest that a number of genera are not monophyletic, including Lycosa, Arctosa, Alopecosa, and Artoria. At the subfamilial level, the status of Pardosinae needs to be re-assessed, and the position of a number of genera within their respective subfamilies is in doubt (e.g., Hippasa and Arctosa in Lycosinae and Xerolycosa, Aulonia and Hygrolycosa in Venoniinae). In addition, a major clade of strictly Australasian taxa may require the creation of a new subfamily. The analysis of sheet-web building in Lycosidae revealed that the interpretation of this trait as an ancestral state relies on two factors: (1) an asymmetrical model favoring the loss of sheet-webs and (2) that the suspended silken tube of Pirata is directly descended from sheet-web building. Paralogous copies of the nuclear 28S rRNA gene were sequenced, confounding the interpretation of the phylogenetic analysis and suggesting that a cautionary approach should be taken to the further use of this gene for lycosid phylogenetic analysis.     

PHYLOGENY AND GENETIC VARIANCE IN TERRESTRIAL MICROCOLEUS (CYANOPHYCEAE) SPECIES BASED ON SEQUENCE ANALYSIS OF THE 16S rRNA GENE AND ASSOCIATED 16S–23S ITS REGION1

Thirty‐one strains of Microcoleus were isolated from desert soils in the United States. Although all these taxa fit the broad definition of Microcoleus vaginatus (Vaucher) Gomont in common usage by soil algal researchers, sequence data for the 16S rRNA gene and 16S–23S internal transcribed spacer (ITS) region indicated that more than one species was represented. Combined sequence and morphological data revealed the presence of two morphologically similar taxa, M. vaginatus and Microcoleus steenstrupii Boye‐Petersen. The rRNA operons of these taxa were sufficiently dissimilar that we suspect the two taxa belong in separate genera. The M. vaginatus clade was most similar to published sequences from Trichodesmium and Arthrospira. When 16S sequences from the isolates we identified as M. steenstrupii were compared with published sequences, our strains grouped with M. chthonoplastes (Mertens) Zanardini ex Gomont and may have closest relatives among several genera in the Phormidiaceae. Organization within the 16S–23S ITS regions was variable between the two taxa. Microcoleus vaginatus had either two tRNA genes (tRNA^Ile and tRNA^Ala) or a fragment of the tRNA^Ile gene in its ITS regions, whereas M. steenstrupii had rRNA operons with either the tRNA^Ile gene or no tRNA genes in its ITS regions. Microcoleus vaginatus showed no subspecific variation within the combined morphological and molecular characterizations, with 16S similarities ranging from 97.1% to 99.9%. Microcoleus steenstrupii showed considerable genetic variability, with 16S similarities ranging from 91.5% to 99.4%. In phylogenetic analyses, we found that this variability was not congruent with geography, and we suspect that our M. steenstrupii strains represent several cryptic species.     

Turkey fecal microbial community structure and functional gene diversity revealed by 16S rRNA gene and metagenomic sequences

The primary goal of this study was to better understand the microbial composition and functional genetic diversity associated with turkey fecal communities. To achieve this, 16S rRNA gene and metagenomic clone libraries were sequenced from turkey fecal samples. The analysis of 382 16S rRNA gene sequences showed that the most abundant bacteria were closely related to Lactobacillales (47%), Bacillales (31%), and Clostridiales (11%). Actinomycetales, Enterobacteriales, and Bacteroidales sequences were also identified, but represented a smaller part of the community. The analysis of 379 metagenomic sequences showed that most clones were similar to bacterial protein sequences (58%). Bacteriophage (10%) and avian viruses (3%) sequences were also represented. Of all metagenomic clones potentially encoding for bacterial proteins, most were similar to low G+C Gram-positive bacterial proteins, particularly from Lactobacillales (50%), Bacillales (11%), and Clostridiales (8%). Bioinformatic analyses suggested the presence of genes encoding for membrane proteins, lipoproteins, hydrolases, and functional genes associated with the metabolism of nitrogen and sulfur containing compounds. The results from this study further confirmed the predominance of Firmicutes in the avian gut and highlight the value of coupling 16S rRNA gene and metagenomic sequencing data analysis to study the microbial composition of avian fecal microbial communities.     

基于12S,16S和28S rRNA基因序列的中国小毛瓢虫属系统发育分析

【目的】小毛瓢虫属Scymnus Kugelann昆虫主要捕食蚜虫、蚧虫等害虫,是一类经济上重要的天敌昆虫。目前针对小毛瓢虫属的系统发育研究尚属空白,亚属之间的系统演化关系尚不明确,为了建立合理的分类系统,亟需对小毛瓢虫属的亲缘关系进行研究和探讨。【方法】以华南农业大学馆藏的小毛瓢虫属5亚属共44种为研究对象,采用PCR技术对12S, 16S和28S rRNA基因的部分序列进行扩增;运用MEGA 7.0分析了小毛瓢虫属内12S, 16S和28S rRNA基因的碱基组成,基于K2P模型计算了小毛瓢虫属44种的种间遗传距离;采用最大似然法(maximum-likelihood, ML)和贝叶斯推断法(Bayesian-inference, BI)构建该属的系统发育树。【结果】扩增获得小毛瓢虫属44种的12S rRNA基因序列平均长度为356 bp, 16S rRNA基因序列平均长度为351 bp, 28S rRNA基因序列平均长度为315 bp;序列分析表明,12S rRNA基因的A, T, G和C平均含量分别为38.8%, 43.5%, 11.9%和5.8%, 16S rRNA基因的A, T, G和C平均含量分别为37.6%, 40.3%, 14.4%和7.7%, 28S rRNA基因的A, T, G和C平均含量分别为26.7%, 18.3%, 31.4%和23.5%;基于联合序列分析的种间遗传距离为0.004～0.276,平均遗传距离为0.115。系统发育分析结果表明,小毛瓢虫属为单系起源,而小毛瓢虫亚属Scymnus(Scymnus) Kugelann、毛瓢虫亚属Scymnus(Neopullus) Sasaji、小瓢虫亚属Scymnus(Pullus) Mulsant和拟小瓢虫亚属Scymnus(Parapullus) Yang均为并系起源。【结论】基于12S, 16S和28S rRNA基因序列的小毛瓢虫属系统发育分析显示传统的形态学分类体系与基于分子数据分析的结果部分不一致,这表明应该对该属内各亚属的鉴别特征进行全面检视,筛选并确立各亚属的形态指标,同时也表明该属内的亚属分类单元需重新厘定。     

Interactions among coexisting larval Odonata: an in situ experiment using small enclosures

Field experiments using small replicated enclosures focused on interactions between larval populations of Epitheca cynosura and Ladona deplanata (Odonata: Anisoptera) — two species that emerge in early spring. The presence of Epitheca reduced the total biomass of Ladona, but Ladona had no significant effect on Epitheca. These early-emerging species reduced the biomass of small instars of late-emerging Anisoptera which colonized enclosures during the experiments; and the late-emerging Anisoptera seem to have inhibited colonization by Zygoptera larvae. Results are consistent with the importance of predatory (cannibalism or mutual predation) interactions in this community.     

Temperature-body size responses in insects: a case study of British Odonata

1. Body size is highly correlated with physiological traits, fitness, and trophic interactions. These traits are subject to change if there are widespread reductions of body size with warming temperatures, which is suggested as one of the ‘universal’ ecological responses to climate change. However, general patterns of body size response to temperature in insects have not yet emerged. 2. To address this knowledge gap, we paired the wing length (as a proxy for body size) of 5331 museum specimens of 14 species of British Odonata with historical temperature data. Three sets of analyses were performed: (i) a regression analysis to test for a relationship between wing length and mean seasonal temperature within species and subsequent comparisons across species and suborders; (ii) an investigation of whether the body size of species has an effect on sensitivity to warming temperature; and (iii) a linear-mixed effects model to investigate factors that potentially affect temperature–size response. 3. The regression analysis indicated that wing length is negatively correlated with mean seasonal temperatures for Zygoptera, whereas Anisoptera showed no significant correlation with temperature. 4. There is a significant decline in wing length of all Zygoptera (but not Anisoptera) with collection date, suggesting that individuals emerging later in the season are smaller. 5. Life-cycle type was not important for predicting wing length–temperature responses, whereas sex, species, and suborder were indicated as important factors affecting the magnitude of temperature–size responses in Odonata. 6. Overall, wing lengths of Zygoptera are more sensitive to temperature and collection date than Anisoptera.     

An Analysis of Marsupial Interordinal Relationships Based on 12S rRNA, tRNA Valine, 16S rRNA, and Cytochrome b Sequences

The basal split among living marsupials is traditionally placed between the cohorts Ameridelphiaand Australidelphia. Ameridelphia includes all American forms excepting the South AmericanDramicuipx gliroidex (Order Microbiotheria). Australidelphia includes all Australasian taxaplus Dromiciops glinmles. DNA data support Eometatheria Dromiciaps + Diprotodontia +Dasyuromorphia + Notoryctemorphia) but do not resolve the position of bandicoots, whetherwith other australidelphians or with ameridelphians. Also, the most robust molecular trees (DNAhybridization, multigene studies) exhibit minimal branch subdivision and raise the possibility ofartit'actual associations owing to long branch attraction. We analyzed data sets that consistedof complete sequences tor four niitochondrial genes (cytochrome b, 12S rRNA, tRNA valine,16S rRNA). One data set included 14 marsupial taxa. A second data set included 14 marsupialsas well as outgroup sequences (one monolreme; 20 placentals). Phylogenetic analyses includedparsimony, minimum evolution, maximum likelihood, and quartet puzzling. When phylogeneticanalyses were restricted to just the marsupial sequences, there was 75 to 96% boostrap supportfor the separation of Ameridelphia versus Australidelphia. This suggests that either one orboth of these groups are monophyletic. Also, there was 71 to 98% bootstrap support for theseparation of Eometatheria versus Ameridelphia + Peramelina. Nonmonophyly of several a prioriclades was accepted by at least some statistical tests including the following: Diprotodontia+ Peramelina, Notoryctemorphia + Peramelina, Diprotodonlia + Notoryctemorphia, and themonophyly of Australasian marsupials. With the inclusion of outgroup sequences, there wasreduced bootstrap support for associations among marsupial orders and statistical tests failed toreject all interordinal associations that were tested.