New evolutionary evidence of Grylloblattida from the Middle Jurassic of Inner Mongolia, north-east China (Insecta, Polyneoptera)

The small modern insect order Grylloblattida has an abundant fossil record during the Late Palaeozoic and the Mesozoicirca. The relationships between these fossil taxa and the modern grylloblattids remain unclear because most of them are based on isolated wings or have poorly preserved body features. Modern grylloblattids are wingless insects. The new grylloblattid family Plesioblattogryllidae fam. nov. is erected for the new genus and species Plesioblattogryllus magnificus gen. nov., sp. nov. , from the Middle Jurassic of north-eastern China. The well-preserved specimen provides further evidence that could support its close relationships with the modern grylloblattids: (1) several very similar head structures, e.g. developed laciniae with inner row of setae, maxillary palps segmented into five, labial palps segmented into three, large labrum, and morphology of antenna; (2) paired eoplantulae on tarsomeres 1–4; (3) long ovipositor and large eggs comparable with those of modern taxa. The new genus has strongly developed mandibles with sharp pointed apical teeth and strong marginal teeth, and strong hook-like fore claws with basal teeth, suggesting it was carnivorous. The major differences between the extinct and extant Grylloblattida, such as the lack of wings, the eyes and ocelli either degenerated or absent, and the thorax degenerated in the modern forms, are probably related to their adaptation to their life under rocks and rock-crawler habits.  © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society , 2008, 152 , 17–24.     

Analysis of larval segmentation in lethal genotypes associated with the antennapedia gene complex in Drosophila melanogaster

The segment pattern of larval cuticular structures was examined for individuals bearing lethal genotypes associated with the Antennapedia gene complex (ANT-C). The results provide new evidence for the role of this complex in body segmentation in Drosophila and demonstrate that the ANT-C, like the bithorax complex, effects both larval and imaginal tissues. Lethal genotypes involving new EMS induced lesions or dominant homoeotic mutations (Antp or Antp^Scx) of the Antennapedia complementation group show anomalies in the larval meso- and metathorax. The phenotype is interpreted as a homoeotic transformation of the meso- and metathorax to prothorax. We suggest that Antp⁺ functions in the elicitation of mesothoracic development above that of a prothoracic level in the ventral meso- and metathorax. The lethality of the Sex combs reduced complementation group, which includes the mutation Multiple sex combs (Msc), is characterized by incomplete head formation and the lack of definitive prothoracic ventral setal belts. These results indicate that Scr⁺ is necessary for normal development of the prothorax and are consistent with earlier interpretations based on adult phenotypes. Five other lethal complementation sites, assigned to polytene chromosome interval 84A-B1,2 have been analyzed. They are not associated with dominant homoeotic phenotypes in the adult. The terminal phenotype of individuals carrying lethal mutations in the W36, R11, or R14 complementation groups demonstrate that these loci are important in normal anterior development and/or body segmentation and suggest functional relationships to the homoeotic mutations previously localized to the 84A-84B1,2 polytene interval.     

The thoracic morphology of cave-dwelling and free-living ground beetles from China (Coleoptera,Carabidae, Trechinae)

External and internal thoracic structures of two carabid species (Trechini) were examined and documented with different techniques. The study has a main focus on the eyeless cave-dwelling specialist Sinaphaenops wangorum, but detailed information is also provided for a species occurring in cave entrances. The phylogenetic background of the structural features of the thoracic skeletomuscular system was addressed. The thoracic morphology of the examined species was compared to conditions observed in previously studied carabids and non-related subterranean leiodids (Staphylinoidea) in order to identify cave adaptations. Main thoracic character complexes linked with cavernicolous habits in Trechini are elongation of the pro- and mesothorax and the legs, and a complete and irreversible reduction of the flight apparatus. The lost flight capacity is linked with a far reaching modification of skeletal elements of the metathorax including a strongly shortened and simplified metanotum, a shortened metaventrite, and completely reduced wings and sclerites of the wing base. The elongate prothorax together with the long and slender head and elongated legs distinctly increases the activity range in the subterranean lightless environment, which likely facilitates foraging of the carnivorous beetles. Some of the observed features like wing loss and elongation of the anterior thorax and legs are also found in some cave-dwelling Leiodidae (Leptodirini), whereas some other subterranean members of the staphylinoid family have a compact body and legs of normal length. In contrast to the predaceous Trechini, Leptodirini are scavengers.     

Wing-hearts in Mecoptera (insecta)

The accessory pulsatile organs for hemolymph circulation in the wings of 7 Mecoptera species were investigated by means of serial semi-thin sections, SEM and TEM. The wing-hearts are located in the dorsal meso- and metathorax, and have no connection to the aorta. Each wing-heart consists of a small hemolymph chamber formed above by the convex scutellum, and below by a horizontal muscular diaphragm. The chamber is connected to the posterior wing veins by a cuticular tube on each side of the body. The diaphragm (10–15 μm thick) is convex in cross-section and consists of transversely extended muscle fibers. Their ultrastructure reveals typical characters of myocardial and other visceral muscle fibers. The diaphragm muscle is innervated by a pair of thin nerves originating from the thoracic ganglion of each corresponding segment. The diaphragm is held in a convex position by numerous elastic strands (2 μm in diameter), which extend through the wing-heart lumen between the scutellum and the diaphragm. The diastolic phase of the wing-heart is caused by contraction of the diaphragm muscle fibers. Thus, the diaphragm flattens and hemolymph is drawn from the posterior wing veins. The systolic phase is caused by the elasticity of the suspending strands after relaxation of the muscle fibers. The elastic strands pull the diaphragm back into convex position and hemolymph is expelled out of the scutellum lumen into the thorax cavity through a valvular opening on the anterior side. The hemolymph flow from the posterior wing base to the scutellum lumen, was visualized by staining the hemolymph. In Panorpa communis the volume of the wing-heart lumen measures 1.6 × 10⁻² mm³ in the mesothorax, and 1.2 × 10⁻² mm³ in the metathorax. Each heartbeat transports a maximum of 65% of these volumes. The pumping frequency was 78 ± 20 beats per min, registered with a non-invasive photo-optical method in restrained animals. Corresponding pulsating movements occur as a passive phenomenon of wing-heart activity in a distinct area of the wing base. Only minor differences were found in the construction of wing-hearts among the investigated species, except for Boreus hyemalis, which lacks these accessory circulatory organs. The functional morphology of the wing-hearts in Mecoptera is compared with that of other Holometabola and aspects of the evolution of these organs are discussed.     

The thorax of Mantophasmatodea,the morphology of flightlessness,and the evolution of the neopteran insects

Mantophasmatodea was described as a new insect order in 2002. Since then, this small group of wingless insects has developed into one of the best investigated insect taxa. Nevertheless, many aspects of mantophasmatodean morphology as well as their evolutionary relationships remain ambiguous. To determine the phylogenetic relationships of Mantophasmatodea based on an extended character set and to elucidate possible morphological adaptions towards flightlessness, we investigated the thoracic morphology of two species, Austrophasma caledonensis and Mantophasma sp. The morphological similarity between these two species is striking and no differences in musculature were found. The mantophasmatodean thorax strongly resembles that of ice crawlers (Grylloblattodea), especially with respect to the presence of pleural processes in the meso‐ and metathorax, branched furcae in all segments, and similar muscle equipment. In a cladistic analysis containing all major lineages of Neoptera, the monophyly of Polyneoptera is supported by the presence of an anal fan and several modifications of the wing joint. Within Polyneoptera, a sister‐group relationship between stoneflies and the remaining Polyneoptera is supported. A clade comprising Mantophasmatodea and the Grylloblattodea gains strong support from thoracic morphology and can be considered assured. Potential thoracic apomorphies include prothoracic paracoxal invaginations, pterothoracic pleural arms that originate from the epimeron, and a unique metathoracic sterno‐coxal musculature. The monophyly of Orthoptera and Dictyoptera is further supported while the deeper polyneopteran nodes remain unresolved. Among the wingless taxa investigated we found few general morphological adaptations whereas, in other aspects, especially in the musculature, strong differences could be observed. However, much more research on the strongly neglected topic of flightlessness is required to make reliable statements.     

Phylogeny and biogeography of ice crawlers (Insecta: Grylloblattodea) based on six molecular loci: designating conservation status for Grylloblattodea species

Ice crawlers (Insecta: Grylloblattodea) are rarely encountered insects that consist of five genera representing 26 species from North America and Asia. Asian grylloblattids are the most diverse, but North American ice crawlers (genus Grylloblatta) are known for their adaptation to cold conditions. Phylogenetic relationships among grylloblattid species and genera are not known. Six genes were sampled in 35 individuals for 18S rRNA, 28S rRNA, histone 3, 12S rRNA, 16S rRNA, and cytochrome oxidase II from 21 populations of Grylloblatta, three populations from Japan (genus Galloisiana), and three populations from Russia (genus Grylloblattina). Phylogenetic analysis of these data with two mantophasmid outgroups in POY supported monophyletic genera, with Grylloblatta as sister to Grylloblattina. Grylloblatta was shown to contain two major lineages: a clade in Northern California and Oregon and a clade in Washington and Oregon. One new species and six candidate species are proposed. IUCN Red List Conservation Criteria were implemented to designate conservation status for each lineage.     

Extremely miniaturised and highly complex: The thoracic morphology of the first instar larva of Mengenilla chobauti (Insecta,Strepsiptera)

Thoracic structures of the extremely small first instar larva of the strepsipteran species Mengenilla chobauti (ca. 200 μm) were examined, described and reconstructed 3-dimensionally. The focus is on the skeletomuscular system. The characters were compared to conditions found in other insect larvae of very small (Ptiliidae) or large (Dytiscus) size (both Coleoptera) and features of “triungulin” larvae, first instar larvae of Rhipiphoridae, Meloidae (both Coleoptera), and Mantispidae (Neuroptera).The specific lifestyle and the extreme degree of miniaturisation result in numerous thoracic modifications. Many sclerites of the exo- and endoskeleton are reduced. Cervical sclerites, pleural ridges, furcae and spinae are absent. Most of the longitudinal muscles are connected within the thorax, and a pair of ventral longitudinal muscles is present in the pleural region of the meso- and metathorax. This results in a high intersegmental flexibility. Due to the size reduction and the correlated shift of the brain to the thorax, with 94 identified muscles the thoracic musculature appears highly compact. Compared to larger larvae the number of both the individual muscles and the muscle bundles are distinctly reduced. The thorax of the first instar larvae displays many additional strepsipteran autapomorphies. At least partly due to the highly specialised condition, potential synapomorphies with other groups were not found.     

Morphological Diversity of the Skeletal Structures and Problems of Classification of Fleas (Siphonaptera). Part 6

The structure of 76 skeletal elements of adult fleas was analyzed, and the distribution of 114 characters with 446 character states over the body tagmata, segments, and morphofunctional complexes was investigated. Among them, 40% of the characters (40) and their states (163) describe the diversity of the structures of the frontal complex (including those of the head and prothorax), which is related to the specific features of flea parasitism. A large part of the characters (18) and their states (83) describe the structures of the nototrochanteral complex of the meso- and metathorax responsible for jumping. The total number of all types of homoplasies (258 states) is almost 1.8 times as great as the number of the states (145) that may be regarded as synapomorphies. The ancestral states (43) comprise a smaller portion of the total number. The proportion of the synapomorphic and homoplastic character states varies between the morphofunctional complexes.     

Coevolution between flight morphology,vertical stratification and sexual dimorphism: what can we learn from tropical butterflies?

Occurrence patterns are partly shaped by the affinity of species with habitat conditions. For winged organisms, flight‐related attributes are vital for ecological performance. However, due to the different reproductive roles of each sex, we expect divergence in flight energy budget, and consequently different selection responses between sexes. We used tropical frugivorous butterflies as models to investigate coevolution between flight morphology, sex dimorphism and vertical stratification. We studied 94 species of Amazonian fruit‐feeding butterflies sampled in seven sites across 3341 ha. We used wing–thorax ratio as a proxy for flight capacity and hierarchical Bayesian modelling to estimate stratum preference. We detected a strong phylogenetic signal in wing–thorax ratio in both sexes. Stouter fast‐flying species preferred the canopy, whereas more slender slow‐flying species preferred the understorey. However, this relationship was stronger in females than in males, suggesting that female phenotype associates more intimately with habitat conditions. Within species, males were stouter than females and sexual dimorphism was sharper in understorey species. Because trait–habitat relationships were independent from phylogeny, the matching between flight morphology and stratum preference is more likely to reflect adaptive radiation than shared ancestry. This study sheds light on the impact of flight and sexual dimorphism on the evolution and ecological adaptation of flying organisms.     

Evidence of different thermoregulatory mechanisms between two sympatric Scarabaeus species using infrared thermography and micro-computer tomography

In endotherms insects, the thermoregulatory mechanisms modulate heat transfer from the thorax to the abdomen to avoid overheating or cooling in order to obtain a prolonged flight performance. Scarabaeus sacer and S. cicatricosus, two sympatric species with the same habitat and food preferences, showed daily temporal segregation with S. cicatricosus being more active during warmer hours of the day in opposition to S. sacer who avoid it. In the case of S. sacer, their endothermy pattern suggested an adaptive capacity for thorax heat retention. In S. cicatricosus, an active 'heat exchanger' mechanism was suggested. However, no empirical evidence had been documented until now. Thermographic sequences recorded during flight performance showed evidence of the existence of both thermoregulatory mechanisms. In S. sacer, infrared sequences showed a possible heat insulator (passive thermal window), which prevents heat transfer from meso- and metathorax to the abdomen during flight. In S. cicatricosus, infrared sequences revealed clear and effective heat flow between the thorax and abdomen (abdominal heat transfer) that should be considered the main mechanism of thermoregulation. This was related to a subsequent increase in abdominal pumping (as a cooling mechanism) during flight. Computer microtomography scanning, anatomical dissections and internal air volume measurements showed two possible heat retention mechanisms for S. sacer; the abdominal air sacs and the development of the internal abdominal sternites that could explain the thermoregulation between thorax and abdomen. Our results suggest that interspecific interactions between sympatric species are regulated by very different mechanisms. These mechanisms create unique thermal niches for the different species, thereby preventing competition and modulating spatio-temporal distribution and the composition of dung beetle assemblages.     

中国新纪录属——瘤螳蛉属一新组合和澳蜂螳蛉属中国三新纪录种(脉翅目,螳蛉科)

首次报道了瘤螳蛉属Tuberonotha在中国的分布,对原"华安螳蛉Entanoneur asinica Yang,1999"进行了修订和重新描述,建立新组合华瘤螳蛉Tuberonoth asini cacomb.nov.;报道了中国螳蛉另一属——澳蜂螳蛉属Austroclimaciella的中国3新纪录种:吕宋澳蜂螳蛉A.luzonica(Weele)、小褐澳蜂螳蛉A.subfusca(Nakahara)和韦氏澳蜂螳蛉A.weelei Handschin,并对拉氏澳蜂螳蛉A.lacolombierei(Navás)进行了重新描述。编写了中国澳蜂螳蛉属检索表,首次对该两属的外生殖器进行了解剖描述和绘图。研究标本保存在中国农业大学昆虫标本馆(CAU)和中国科学院动物研究所动物标本馆(IOZ)。     

Dominibrentus leptus,n. gen., n. sp. (Curculionoidea,Brentidae, Cyphagoginae,Dominibrentini, n. tribe), a straight-snouted weevil in Dominican amber

A new tribe, genus and species of straight-snouted weevils (Dominibrentus leptus, n. gen., n. sp., Dominibrentini, n. tribe; Coleoptera: Brentidae; Cyphagoginae) has been described from Dominican amber. The new taxon is characterised by compressed, ventrolateral concavities on the prothorax and abdomen and lateral concavities on the metathorax for reception of the legs. This is the first representative of a straight-snouted weevil in amber.     

Ecological implications of the correlation of avian footprints with wing characteristics: a mathematical approach

The characteristics of avian wings that evolved for flying appear to show a distinct relationship to the shape of the pes and walking abilities as reflected in footprints. Wing area, wing span and body weight data of modern birds were collected and analysed in order to quantify the possible correlation, which was previously only inferred from empirical data. Discriminant analysis demonstrated that avian wings can be divided into three habitat groups, in a similar way to footprints. Multiple regression analyses revealed that the avian wing loading and aspect ratio were correlated with the parameters of footprint shape and can be expressed by a simple equation. The results may reflect the adaptation of avian locomotion to habitat. The relationships between wing area and wing span, and between wing area and footprint area, which are apparent in modern avians, were derived and used to estimate wing area and wing span from the footprints of extinct Cretaceous avian taxa. The estimated values of body weight, wing span and wing area suggest that the trackmakers of Archaeornithipus meijidei, Hwangsanipes choughi and Yacoraitichnus avis had bodies similar to herons (or cranes), large sandpipers (or small sea birds) and medium‐sized gull‐like birds, respectively.     

The morphology of larvae and systematics of the leaf-beetles Chrysolina tundralis and Chrysolina roddi (Coleoptera, Chrysomelidae, Chrysomelinae)

The 1st- and 4th-instar larvae of Chrysolina tundralis and Ch. roddi and the egg of the latter species are described for the first time; the instar-related changes of the larval morphology are discussed. The 4th-instar larva of Ch. tundralis is very similar to that of Ch. septentrionalis, but differs in the smaller sclerite-like plates of the abdominal segments and wider spaces between them (4–7 times as wide as a sclerite-like plate). The 4th-instar larva of Ch. roddi is very similar to that of Ch. pedestris, but differs in the dark brown coloration of the body and a fewer number of setae (9–12) in the dorsolateral areas of the meso- and metathorax. Data on the habitats and host plants of the larvae are given.     

普通齿蛉幼虫的呼吸系统及呼吸行为

研究了普通齿蛉Neoneuromus ignobilis Navás幼虫的呼吸系统及其呼吸行为。结果表明:普通齿蛉幼虫为全气门式(10对气门)呼吸系统,前中胸、中后胸之间、腹部8节各有1对气门,腹部8节各有气管鳃1对,前6对细短,管状,有较短绒毛,后2对气管鳃较粗长,呈羽毛状。腹部1～7节各有1对毛簇,第8腹节无毛簇。侧纵干气管较粗,4束,自前胸前缘部分成左右2组,每组两根侧纵干气管,向胸腹部延伸,二级气管分别伸达各个气门和毛簇,腹部每节由毛簇处的二级气管分支而来的三级气管相连或延伸至消化道等处。气管鳃中无气管。有毛簇呼吸、气门呼吸和体壁呼吸3种呼吸方式,在水中以毛簇呼吸为主,在陆上进行气门呼吸和体壁呼吸。     

Influence of Evolutionary Allometry on Rates of Morphological Evolution and Disparity in strictly Subterranean Moles (Talpinae,Talpidae, Lipotyphla,Mammalia)

The adaptation to a particular function could directly influence the morphological evolution of an anatomical structure as well as its rates. The humeral morphology of moles (subfamily Talpinae) is highly modified in response to intense burrowing and fully fossorial lifestyle. However, little is known of the evolutionary pathways that marked its diversification in the two highly fossorial moles tribes Talpini and Scalopini. We used two-dimensional landmark-based geometric morphometrics and comparative methods to understand which factors influenced the rates and patterns of the morphological evolution of the humerus in 53 extant and extinct species of the Talpini (22 extant plus 12 extinct) and Scalopini (six extant plus 13 extinct) tribes, for a total of 623 humeri. We first built a synthetic phylogeny of extinct and extant taxa of the subfamily Talpinae based on all the available information from known phylogenies, molecular data, and age ranges of fossil records. We tested for evolutionary allometry by means of multivariate regression of shape on size variables. Evolutionary allometric trajectories exhibited convergence of humeral shape between the two tribes, even when controlling for phylogeny, though a significant differences in the evolutionary rates was found between the two tribes. Talpini, unlike Scalopini, seem to have reached a robust fossorial morphology early during their evolution, and their shape disparity did not change, if it did not decrease, through time. Furthermore, the basal Geotrypus spp. clearly set apart from the other highly fossorial moles, exhibiting a significant acceleration of evolutionary shifts toward higher degree of fossorial adaptation. Our observations support the hypothesis that the evolution of allometry may reflect a biological demand (in this case functional) that constrains the rates of evolution of anatomical structures.     

Features of the receptors of the alar system of locusts which have lost their ability to fly

Using two species of locusts, Romalia microptera Beavy and Podisma pedestris L., receptors of the wing apparatus are described: campaniform sensillas of the wing, hair receptors of the tegula, chordotonal organ and thorax stretch receptor. A comparative analysis of the receptors mentioned with the homologous sensitive organs, participating in the control of wing movements, is performed in well flying species (Locusta migratoria migratorioides and Schistocerca gregaria). Loss of ability to fly is accompanied with a sharp decrease in the wing campaniform sensillas and in the tegula proprioceptive hairs. Simultaneously, there is loss of connection between the thorax receptors and the wing elements that are present in good flyers. The thorax stretch receptor begins to innervate the longitudinal dorsal muscle, as it is observed in the abdominal segments. The data obtained make it possible to speak about homology of the tergal chordotonal organs and the thorax and abdomen stretch receptors and about the pathways of their evolution, when the insects obtain and loose their ability to fly.     

REACTION NORMS OF MORPHOLOGICAL TRAITS IN DROSOPHILA: ADAPTIVE SHAPE CHANGES IN A STENOTHERM CIRCUMTROPICAL SPECIES?

Reaction norms of wing length, thorax length, and ovariole number were studied according to growth temperature in the circumtropical Drosophila ananassae, and compared to similar data from the cosmopolitan D. melanogaster. In the two species convex reaction norms were observed, but they were not parallel and sometimes exhibited intersections either at high (wing) or at low (thorax) temperature. On average, D. ananassae may be considered as a species with a bigger thorax but shorter wings than D. melanogaster. The shapes of reaction norms were analyzed and compared after quadratic polynomial adjustments. Significant differences were observed, in several cases between polynomial parameters, and in all cases between characteristic points that is, Maximum Value (MV) and Temperature of Maximum Value (TMV). The wing/thorax ratio may also be considered as a specific trait related to wing loading. Major differences were observed between the two species for the mean value and the shape of the response curves of this trait. The main observation of this work was however a shift of TMVs for wing and thorax length and ovariole number in D. ananassae toward higher temperatures. These variations in the reaction norms corresponded to a shift in the species thermal range, suggesting that temperature adaptation was accompanied by a modification of the shape of the response curves.