Computational biomechanics changes our view on insect head evolution

Despite large-scale molecular attempts, the relationships of the basal winged insect lineages dragonflies, mayflies and neopterans, are still unresolved. Other data sources, such as morphology, suffer from unclear functional dependencies of the structures considered, which might mislead phylogenetic inference. Here, we assess this problem by combining for the first time biomechanics with phylogenetics using two advanced engineering techniques, multibody dynamics analysis and finite-element analysis, to objectively identify functional linkages in insect head structures which have been used traditionally to argue basal winged insect relationships. With a biomechanical model of unprecedented detail, we are able to investigate the mechanics of morphological characters under biologically realistic load, i.e. biting. We show that a range of head characters, mainly ridges, endoskeletal elements and joints, are indeed mechanically linked to each other. An analysis of character state correlation in a morphological data matrix focused on head characters shows highly significant correlation of these mechanically linked structures. Phylogenetic tree reconstruction under different data exclusion schemes based on the correlation analysis unambiguously supports a sistergroup relationship of dragonflies and mayflies. The combination of biomechanics and phylogenetics as it is proposed here could be a promising approach to assess functional dependencies in many organisms to increase our understanding of phenotypic evolution.

Paleozoic Nymphal Wing Pads Support Dual Model of Insect Wing Origins

The appearance of wings in insects, early in their evolution [1], has been one of the more critical innovations contributing to their extraordinary diversity. Despite the conspicuousness and importance of wings, the origin of these structures has been difficult to resolve and represented one of the "abominable mysteries" in evolutionary biology [2]. More than a century of debate has boiled the matter down to two competing alternatives-one of wings representing an extension of the thoracic notum, the other stating that they are appendicular derivations from the lateral body wall. Recently, a dual model has been supported by genomic and developmental data [3-6], representing an amalgamation of elements from both the notal and pleural hypotheses. Here, we reveal crucial information from the wing pad joints of Carboniferous palaeodictyopteran insect nymphs using classical and high-tech techniques. These nymphs had three pairs of wing pads that were medially articulated to the thorax but also broadly contiguous with the notum anteriorly and posteriorly (details unobservable in modern insects), supporting their overall origin from the thoracic notum as well as the expected medial, pleural series of axillary sclerites. Our study provides support for the formation of the insect wing from the thoracic notum as well as the already known pleural elements of the arthropodan leg. These results support the unique, dual model for insect wing origins and the convergent reduction of notal fusion in more derived clades, presumably due to wing rotation during development, and they help to bring resolution to this long-standing debate.

Incorporating fossils into hypotheses of insect phylogeny

Fossils represent stem and crown lineages, and their inclusion in phylogenetic reconstruction influences branch lengths, topology, and divergence time estimation. In addition, paleontological data may inform trends in morphological evolution as well as biogeographic history. Here we review the incorporation of fossils in studies of insect evolution, from morphological analyses to combined 'total evidence' node dating analyses. We discuss challenges associated with fossil based phylogenetics, and suggest best practices for use in tree reconstruction.

A review of methods for analysing insect structures - the role of morphology in the age of phylogenomics

Techniques currently used in insect morphology are outlined briefly. Scanning electron microscopy (SEM) and microphotography are used mainly for documenting external features, the former providing more information on tiny surface structures and the latter on coloration, transparency and degree of sclerotization. A broad spectrum of methods is now available for anatomical studies: histological serial sections, confocal laser scanning microscopy (CLSM), light-sheet fluorescence microscopy (LSFM), serial block-face scanning electron microscopy (SBFSEM), dual beam scanning electron microscopy (FIB-SEM), nuclear magnetic resonance imaging (NMRI), and μ-computed tomography (micro-CT). The use of SBFSEM and FIB-SEM is restricted to extremely small samples. NMRI is used mainly in in vivo studies. Micro-computed tomography, in combination with computer-based reconstruction, has greatly accelerated the acquisition of high quality data in a phylogenetic context. Morphology will continue to play a vital role in phylogenetic and evolutionary investigations. It provides independent data for checking the plausibility of molecular phylogenies and is the only source of information for placing extinct taxa. It is the necessary basis for reconstructing character evolution on the phenotypic level and for developing complex evolutionary scenarios. Computer-based anatomical ontologies are an additional future perspective of morphological work.

Siphonobacter intestinalis sp. nov., a bacterium isolated from the feces of Pseudorhynchus japonicus

Strain 63MJ-2^T was isolated from the feces of broad-winged katydid (Pseudorhynchus japonicus) collected in Korea. The 16S rRNA gene sequence of this strain showed the highest sequence similarity with that of Siphonobacter aquaeclarae P2^T (96.1%) and had low similarities (below 86.3%) with those of other members of family 'Flexibacteraceae'. The strain 63MJ-2^T is a strictly aerobic, Gram-stain-negative, non-motile, rod-shaped bacterium. The strain grew at 4-35°C (optimum, 25-30°C), pH of 5.0-9.0 (optimum, 6.0-7.0), and 0-2.0% (optimum, 1.0-2.0) (w/v) NaCl. The DNA G+C content of strain 63MJ-2^T was 43.5 mol%. The major fatty acids were C_16:1 ω5c (42.5%), iso-C_17:0 3-OH (18.7%), and summed feature 3 (iso-C_15:0 2-OH and/or C_16:1 ω7c, 18.0%). The major menaquinone was MK-7 and polar lipids were phosphatidylethanolamine, six unknown aminolipids, and five unknown lipids. Based on the evidence from our polyphasic taxonomic study, we conclude that strain 63MJ-2^T should be classified as a novel species of the genus Siphonobacter, and propose the name Siphonobacter intestinalis sp. nov. The type strain is 63MJ-2^T (=KACC 18663^T =NBRC 111883^T).

Directional hearing in insects with internally coupled ears

Compared to all other hearing animals, insects are the smallest ones, both in absolute terms and in relation to the wavelength of most biologically relevant sounds. The ears of insects can be located at almost any possible body part, such as wings, legs, mouthparts, thorax or abdomen. The interaural distances are generally so small that cues for directional hearing such as interaural time and intensity differences (IITs and IIDs) are also incredibly small, so that the small body size should be a strong constraint for directional hearing. Yet, when tested in behavioral essays for the precision of sound source localization, some species demonstrate hyperacuity in directional hearing and can track a sound source deviating from the midline by only [Formula: see text]-[Formula: see text]. They can do so by using internally coupled ears, where sound pressure can act on both sides of a tympanic membrane. Here we describe their varying anatomy and mode of operation for some insect groups, with a special focus on crickets, exhibiting probably one of the most sophisticated of all internally coupled ears in the animal kingdom.

The phylogeny of brown lacewings (Neuroptera: Hemerobiidae) reveals multiple reductions in wing venation

BACKGROUND

The last time the phylogenetic relationships among members of the family Hemerobiidae were studied quantitatively was over 12 years ago and based exclusively on morphology. Our study builds upon this morphological evidence by adding sequence data from three gene loci to provide a total evidence phylogeny of brown lacewings (Neuroptera: Hemerobiidae). Thirty-seven species representing nineteen Hemerobiidae genera were compared with outgroups from the families Ithonidae, Psychopsidae and Chrysopidae in Bayesian and parsimony analyses using a single nuclear gene (CAD) and two mitochondrial (16S rDNA and Cytochrome Oxidase I) genes. We compare divergence time estimates of Hemerobiidae cladogenesis under the two most commonly used relaxed clock models and discuss the evolution of wing venation in the family.

RESULTS

We recovered a phylogeny largely incongruent with previously published morphological studies, although all but two subfamilies (i.e., Notiobiellinae and Drepanacrinae) were recovered as monophyletic. We found the subfamily Drepanacrinae paraphyletic with respect to Psychobiellinae, and Notiobiellinae to be polyphyletic. We thus offer a revised concept of Notiobiellinae, comprising only Notiobiella Banks, and erect a new subfamily Zachobiellinae including the remaining genera previously placed in Notiobiellinae. Psychobiellinae is synonymized with Drepanacrinae. Unlike the previous hypothesis that proposed a remarkably laddered topology, our tree suggests that hemerobiids diverged as three main clades. Moreover, in contrast to the vein proliferation hypothesis, we found that hemerobiids have instead undergone multiple reductions in the number of radial veins, this scenario questions the relevance of this character as diagnostic of various subfamilies

CONCLUSIONS

Our phylogenetic hypothesis and divergence times analysis suggest that extant hemerobiids originated around the end of the Triassic and evolved as three distinct clades that diverged from one another during the Late Jurassic to Early Cretaceous. Contrary to earlier phylogenetic hypotheses, Carobius Banks (Carobiinae) is sister to the previously unplaced genus Notherobius New in a clade more closely related to Sympherobiinae, Megalominae and Zachobiellinae subfam. nov. The addition of taxa which are not available for DNA sequencing should be the focus of future studies, especially Adelphohemerobius Oswald, which is particularly important to test our inferences regarding the evolution of wing venation in Hemerobiidae.

Revision of the Oriental subfamily Heteropteryginae Kirby, 1896, with a re-arrangement of the family Heteropterygidae and the descriptions of five new species of Haaniella Kirby, 1904. (Phasmatodea: Areolatae: Heteropterygidae)

The areolate Oriental family Heteropterygidae Kirby, 1893 is critically reviewed and the results of the present study contradict the arrangement suggested by Zompro (2004), but in most aspects agree with a molecular study presented by Whiting et al (2003) and a phylogenetic study presented by Bradler (2009). The family is critically discussed and new hypotheses are presented for the phylogeny and intra-familiar relationships, placing the subfamily Dataminae Rehn & Rehn, 1939 as the basalmost clade of Heteropterygidae. The subfamilies Obriminae Brunner v. Wattenwyl, 1893 and Heteropteryginae Kirby, 1893 together represent the sister-group of Dataminae. Arguments and a tree are presented to support this hypothesis. New diagnoses and lists of genera are provided for all three subfamilies contained in Heteropterygidae, along with keys to distinguish between them.        The subfamily Obriminae is critically reviewed and the distinction between the three tribes Obrimini Brunner v. Wattenwyl, 1893, Eubulidini Zompro, 2004 and Miroceramiini Zompro, 2004 introduced by Zompro (2004) is shown to be poorly supported. While Obrimini sensu Zompro, 2004 is generally accepted (but now also contains genera that were placed in Eubulidini or Miroceramiini by Zompro (2004)), the tribes Eubulidini and Miroceramiini are not supported. A new arrangement is introduced, which is based on morphological characters neglected or overlooked by Zompro (2004) but were partly discussed by Bradler (2009). The genus Mearnsiana Rehn & Rehn, 1939 is removed from Miroceramiini and transferred to Obrimini. The genera Eubulides Stål, 1877, Heterocopus Redtenbacher, 1906, Theramenes Stål, 1875 and Stenobrimus Redtenbacher, 1906 are removed from Eubulidini and also transferred to Obrimini. Consequently, Eubulidini is synonymised with Obrimini (n. syn.). Miroceramiini is a monotypical tribe and only includes the Wallacean genus Miroceramia Günther, 1934. The new tribe Tisamenini n. trib. is established for the three basal genera Tisamenus Stål, 1875, Ilocano Rehn & Rehn, 1939 and Hoploclonia Stål, 1875 all of which were placed in Eubulidini by Zompro (2004). The latter genus differs from the other two genera by the morphology of the female genitalia, which is unique amongst the entire family. Three generic groups are recognized within Obrimini, the Obrimus-group, Stenobrimus-group and Theramenes-group. Keys are presented to distinguish between the three tribes now contained in the Obriminae, i.e. Obrimini, Tisamenini n. trib. and Miroceramiini. The genus Hennobrimus Conle, 2006 is synonymised with Mearnsiana Rehn & Rehn, 1939, based on the fact that the type-species of both genera are conspecific (n. syn.). Hennobrimus hennemanni Conle, 2006, the type-species of Hennobrimus, and Trachyaretaon manobo Lit & Eusebio, 2005 are synonymised with Mearnsiana bullosa Rehn & Rehn, 1939, the type-species of Mearnsiana (n. syn.). Theramenes dromedarius Stål, 1877 from the Philippines is removed from synonymy with the Wallacean Theramenes olivaceus (Westwood, 1859) and re-established as a valid species (rev. stat.).        The subfamily Heteropteryginae Kirby, 1896 is revised at the species-level and a new diagnosis is presented. Keys to the two genera and all 16 known species are provided along with new descriptions, differential diagnoses, lists of examined material, detailed information on the known distributions, measurements and illustrations of the insects and eggs. The intra-subfamiliar and intra-generic relationships are discussed and a cladogram is presented. Heteropteryginae contains two genera: Heteropteryx Gray, 1835 (Type-species: Phasma dilatatum Parkinson, 1798) and Haaniella Kirby, 1896 (Type-species: Phasma (Heteropteryx) muelleri de Haan, 1842). The distribution of this subfamily is restricted to Sundaland with the exception of a single species that is found in Vietnam. All other species are distributed in Borneo, Sumatra, the Mentawai Islands, Singapore, Peninsular Malaysia and Thailand. Heteropteryginae contains the largest and most striking members of the entire family Heteropteryginae, some of which are amongst the heaviest insects known. The subfamily is characterized by apomorphies such as the presence of wings, having a tympanal area (= stridulatory organ) in the basal portion of the alae, straight profemora, strongly shortened tarsi, lack of rough sensory-areas on the prosternum and typically X-shaped micropylar plate of the eggs. The sister-group of Heteropteryginae is represented by the Obriminae, with which it shares a beak-like secondary ovipositor in the females and presence of a medio-apical spine on the area apicalis. Both features are synapomorphies of Heteropteryginae + Obriminae.        The genus Haaniella Kirby, 1904 contains 16 known species, five of which are newly described herein. The genus Miniopteryx Zompro, 2004 (Type-species: Haaniella parva Günther, 1944) is synonymised with Haaniella on the basis that the distinguishing feature mentioned in the original description is a character that is frequently found throughout the genus (n. syn.). The type-species H. parva Günther, 1944 is automatically retransferred to Haaniella (rev. stat.). Haaniella aculeata n. sp. from western Sumatra is described from the male. Haaniella macroptera n. sp. from Singapore and the Johor state in southern Peninsular Malaysia is described from both sexes and the eggs. Haaniella gintingi n. sp. from Central Sumatra is described from both sexes and the eggs and Haaniella kerincia n. sp. from Western Sumatra is described from the insects only, the eggs being still unknown. One new species, Haaniella gorochovi n. sp., is the only representative of the genus and subfamily Heteropteryginae known from Vietnam and both sexes as well as the eggs are described. Haaniella erringtoniae (Redtenbacher, 1906) is endemic in Peninsular Malaysia, here removed from synonymy with H. muelleri (de Haan, 1842) and re-established as a valid species (rev. stat.). The Sumatran Haaniella glaber (Redtenbacher, 1906) is removed from synonymy with H. muelleri (Haan, 1842) and re-established as a valid species (rev. stat.). Leocrates glaber Redtenbacher, 1906 and Haaniella muelleri simplex Günther, 1944 are removed from synonymy with H. muelleri (Haan, 1842) (rev. stat.) and synonymised with H. glaber. Haaniella mecheli (Redtenbacher, 1906) and H. rosenbergii (Kaup, 1871) are removed from synonymy with H. muelleri (Haan, 1842) and re-established as valid species (rev. stat.). Haaniella erringtoniae novaeguineae Günther, 1934 and Haaniella muelleri var. b. (Haan, 1842) are synonymized with H. rosenbergii (Kaup, 1871) (n. syn.). The type-species Haaniella muelleri (Haan, 1842) is shown to be a fairly rare species that is restricted to Sumatra. All subsequent records of H. muelleri from outside Sumatra and references to captive breeding of stock originating from Peninsular Malaysia in Europe relate to H. erringtoniae (Redtenbacher, 1906). The previously unknown males and eggs of H. rosenbergii (Kaup, 1871) as well as the previously unknown females and eggs of H. parva Günther, 1944 are described and illustrated for the first time. Based on morphological characters of the insects and eggs three distinct species-groups are recognized within Haaniella. The muelleri species-group contains nine species that are distributed throughout Sumatra, the Mentawei Islands, Singapore and Peninsular Malaysia. These are characterized by the smooth ventral surface of the meso- and metafemora and lemon-shaped eggs which entirely lack the setae seen in the two other species-groups. The grayii species-group comprises four species, two of which are endemic in Borneo, one endemic in Sumatra and the fourth species being the only known representative of the subfamily in Vietnam. These species are characteristic for the prominent pair of spines on the abdominal tergites II-IV of males and long apically multidentate epiproct of females. The echinata species-group contains three exceptionally Bornean species, which are characterized by the long and apically pointed subgenital plate of females, which clearly projects beyond the epiproct, as well as the sub-basal lateral tooth of the anal segment of males. The muelleri species-group is sister to the remainder two species-groups.        Heteropteryx Gray, 1853 is a monotypical genus and only contains the type-species H. dilatata (Parkinson, 1798), which is found throughout Peninsular Malaysia, Thailand, Sumatra and Northeastern Borneo. This genus differs from Haaniella by the strongly conically elevated head, which posteriorly projects over the anterior margin of the pronotum, females being bright green or yellow in colour with plain and translucent pink alae and having distinct spines on the abdominal tergites, and males having a strongly shortened mesothorax and dull pink alae.        Lectotypes are designated for Haaniella parva Günther, 1944, Heteropteryx echinata Redtenbacher, 1906, Heteropteryx saussurei Redtenbacher, 1906 and Heteropteryx scabra Redtenbacher, 1906 to guarantee stability of these names.        Information on the habitats, host-plants, biology, life cycle, parasitism and captive breeding of the species of Heteropteryginae is presented and a list summarising all taxonomic changes presented herein.

Anisotropic shrinkage of insect air sacs revealed in vivo by X-ray microtomography

Air sacs are thought to be the bellows for insect respiration. However, their exact mechanism of action as a bellows remains unclear. A direct way to investigate this problem is in vivo observation of the changes in their three-dimensional structures. Therefore, four-dimensional X-ray phase contrast microtomography is employed to solve this puzzle. Quantitative analysis of three-dimensional image series reveals that the compression of the air sac during respiration in bell crickets exhibits obvious anisotropic characteristics both longitudinally and transversely. Volumetric changes of the tracheal trunks in the prothorax further strengthen the evidence of this finding. As a result, we conclude that the shrinkage and expansion of the insect air sac is anisotropic, contrary to the hypothesis of isotropy, thereby providing new knowledge for further research on the insect respiratory system.

Endocidal Regulation of Secondary Metabolites in the Producing Organisms

Secondary metabolites are defined as organic compounds that are not directly involved in the normal growth, development, and reproduction of an organism. They are widely believed to be responsible for interactions between the producing organism and its environment, with the producer avoiding their toxicities. In our experiments, however, none of the randomly selected 44 species representing different groups of plants and insects can avoid autotoxicity by its endogenous metabolites once made available. We coined the term endocides (endogenous biocides) to describe such metabolites that can poison or inhibit the parent via induced biosynthesis or external applications. Dosage-dependent endocides can selectively induce morphological mutations in the parent organism (e.g., shrubbiness/dwarfism, pleiocotyly, abnormal leaf morphogenesis, disturbed phyllotaxis, fasciated stems, and variegation in plants), inhibit its growth, development, and reproduction and cause death than non-closely related species. The propagule, as well as the organism itself contains or produces adequate endocides to kill itself.

Ultrastructure and Morphology of Compound Eyes of the Scorpionfly Panorpa dubia (Insecta: Mecoptera: Panorpidae)

Mecoptera are unique in holometabolous insects in that their larvae have compound eyes. In the present study the cellular organisation and morphology of the compound eyes of adult individuals of the scorpionfly Panorpa dubia in Mecoptera were investigated by light, scanning electron, and transmission electron microscopy. The results showed that the compound eyes of adult P. dubia are of the apposition type, each eye comprising more than 1200 ommatidia. The ommatidium consists of a cornea, a crystalline cone made up of four cone cells, eight photoreceptors, two primary pigment cells, and 18 secondary pigment cells. The adult ommatidium has a fused rhabdom with eight photoreceptors. Seven photoreceptors extend from the proximal end of the crystalline cone to the basal matrix, whereas the eighth photoreceptor is shorter, extending from the middle level of the photoreceptor cluster to the basal matrix. The fused rhabdom is composed of the rhabdomeres of different photoreceptors at different levels. The adult ommatidia have the same cellular components as the larval ommatidia, but the tiering scheme is different.

Evidence for selective attention in the insect brain

The capacity for selective attention appears to be required by any animal responding to an environment containing multiple objects, although this has been difficult to study in smaller animals such as insects. Clear operational characteristics of attention however make study of this crucial brain function accessible to any animal model. Whereas earlier approaches have relied on freely behaving paradigms placed in an ecologically relevant context, recent tethered preparations have focused on brain imaging and electrophysiology in virtual reality environments. Insight into brain activity during attention-like behavior has revealed key elements of attention in the insect brain. Surprisingly, a variety of brain structures appear to be involved, suggesting that even in the smallest brains attention might involve widespread coordination of neural activity.

Evaluation of native plant flower characteristics for conservation biological control of Prays oleae

Several studies have shown that manipulating flowering weeds within an agroecosystem can have an important role in pest control by natural enemies, by providing them nectar and pollen, which are significant sources of nutrition for adults. The aim of this study was to assess if the olive moth, Prays oleae (Bernard, 1788) (Lepidoptera: Praydidae), and five of its main natural enemies, the parasitoid species Chelonus elaeaphilus Silvestri (Hymenoptera: Braconidae), Apanteles xanthostigma (Haliday) (Hymenoptera: Braconidae), Ageniaspis fuscicollis (Dalman) (Hymenoptera: Encyrtidae) and Elasmus flabellatus (Fonscolombe) (Hymenoptera: Eulophidae), as well as the predator Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae), can theoretically access the nectar from 21 flowering weeds that naturally occur in olive groves. Thus, the architecture of the flowers as well as the mouthpart structure and/or the head and thorax width of the pest and its enemies were analyzed. The results suggested that all beneficial insects were able to reach nectar of the plant species from Apiaceae family, i.e. Conopodium majus (Gouan) Loret, Daucus carota L. and Foeniculum vulgare Mill., as well as Asparagus acutifolius L., Echium plantagineum L., Capsella bursa-pastoris (L.) Medik., Raphanus raphanistrum L., Lonicera hispanica Boiss. et Reut., Silene gallica L., Spergula arvensis L., Hypericum perforatum L., Calamintha baetica Boiss. et Reut, Malva neglecta Wallr. and Linaria saxatilis (L.) Chaz. P. oleae was not able to access nectar from five plant species, namely: Andryala integrifolia L., Chondrilla juncea L., Dittrichia viscosa (L.) Greuter, Sonchus asper (L.) Hill and Lavandula stoechas L.

New fossil insect order Permopsocida elucidates major radiation and evolution of suction feeding in hemimetabolous insects (Hexapoda: Acercaria)

With nearly 100,000 species, the Acercaria (lice, plant lices, thrips, bugs) including number of economically important species is one of the most successful insect lineages. However, its phylogeny and evolution of mouthparts among other issues remain debatable. Here new methods of preparation permitted the comprehensive anatomical description of insect inclusions from mid-Cretaceous Burmese amber in astonishing detail. These "missing links" fossils, attributed to a new order Permopsocida, provide crucial evidence for reconstructing the phylogenetic relationships in the Acercaria, supporting its monophyly, and questioning the position of Psocodea as sister group of holometabolans in the most recent phylogenomic study. Permopsocida resolves as sister group of Thripida + Hemiptera and represents an evolutionary link documenting the transition from chewing to piercing mouthparts in relation to suction feeding. Identification of gut contents as angiosperm pollen documents an ecological role of Permopsocida as early pollen feeders with relatively unspecialized mouthparts. This group existed for 185 million years, but has never been diverse and was superseded by new pollenivorous pollinators during the Cretaceous co-evolution of insects and flowers. The key innovation of suction feeding with piercing mouthparts is identified as main event that triggered the huge post-Carboniferous radiation of hemipterans, and facilitated the spreading of pathogenic vectors.

A defensive behavior and plant-insect interaction in Early Cretaceous amber--The case of the immature lacewing Hallucinochrysa diogenesi

Amber holds special paleobiological significance due to its ability to preserve direct evidence of biotic interactions and animal behaviors for millions of years. Here we review the finding of Hallucinochrysa diogenesi Pérez-de la Fuente, Delclòs, Peñalver and Engel, 2012, a morphologically atypical larva related to modern green lacewings (Insecta: Neuroptera) that was described in Early Cretaceous amber from the El Soplao outcrop (northern Spain). The fossil larva is preserved with a dense cloud of fern trichomes that corresponds to the trash packet the insect gathered and carried on its back for camouflaging and shielding, similar to that which is done by its extant relatives. This finding supports the prominent role of wildfires in the paleoecosystem and provides direct evidence of both an ancient plant-insect interaction and an early acquisition of a defensive behavior in an insect lineage. Overall, the fossil of H. diogenesi showcases the potential that the amber record offers to reconstruct not only the morphology of fossil arthropods but, more remarkably, their lifestyles and ecological relationships.

Allometry and size control: what can studies of body size regulation teach us about the evolution of morphological scaling relationships?

The relationship between organ and body size, known as morphological allometry, has fascinated biologists for over a century because changes in allometry generate the vast diversity of organism shapes. Nevertheless, progress has been limited in understanding the genetic mechanisms that regulate allometries and how these mechanisms evolve. This is perhaps because allometry is measured at the population level, however adult organ and body size depends on genetic background and the developmental environment of individuals. Recent findings have enhanced our understanding of how insects regulate their organ and body sizes in response to environmental conditions, particularly nutritional availability. We argue that merging these developmental insights with a population genetics approach will provide a powerful system for understanding the evolution of allometry.

Morphogenetic functions of extraembryonic membranes in insects

Morphogenetic functions of the amnioserosa, the serosa, the amnion, and the yolk sac are reviewed on the basis of recent studies in flies (Drosophila, Megaselia), beetles (Tribolium), and hemipteran bugs (Oncopeltus). Three hypotheses are presented. First, it is suggested that the amnioserosa of Drosophila and the dorsal amnion of other fly species function in a similar manner. Second, it is proposed that in many species with an amniotic cavity, the amnion determines the site of serosa rupture, which, through interactions between the serosa and the amnion, enables the embryo to break free from the amniotic cavity and to close its backside. Finally, it is concluded that the yolk sac is likely an important player in insect morphogenesis.

Chemical Ecology of Neuroptera

With 6,000 species, Neuroptera (lacewings, antlions, dustywings, and allies) is a relatively small order; however, most larval neuropterans are predacious, often in agricultural systems, lending added importance to this group. Advances in neuropteran phylogeny, most recently through genomic studies, stabilized the nomenclature of this ancestral order of Holometabola, facilitating basic and applied research on these important and interesting insects. The first pheromones for green lacewings (Chrysopidae) have been identified; this, and other research on antlions (Myrmeleontidae), suggests that male-produced long-range pheromones are the norm for the order. Characterizations of the myriad neuropteran exocrine gland systems, including prothoracic, metathoracic, abdominal, dermal, and anal glands, are revealing unforeseen trophic relationships with biological control implications. For examples, males of Chrysopa and other lacewing genera evidently must sequester specific chemical precursors from prey or plants to produce their attractant pheromones, and larval antlion venoms are potentially important genetic leads for insecticidal peptides.

Hearing in Insects

Insect hearing has independently evolved multiple times in the context of intraspecific communication and predator detection by transforming proprioceptive organs into ears. Research over the past decade, ranging from the biophysics of sound reception to molecular aspects of auditory transduction to the neuronal mechanisms of auditory signal processing, has greatly advanced our understanding of how insects hear. Apart from evolutionary innovations that seem unique to insect hearing, parallels between insect and vertebrate auditory systems have been uncovered, and the auditory sensory cells of insects and vertebrates turned out to be evolutionarily related. This review summarizes our current understanding of insect hearing. It also discusses recent advances in insect auditory research, which have put forward insect auditory systems for studying biological aspects that extend beyond hearing, such as cilium function, neuronal signal computation, and sensory system evolution.

The Jurassic Bajanzhargalanidae (Insecta: Grylloblattida?): New genera and species, and data on postabdominal morphology

The presumed phylogenetic link between extant ice-crawlers (Grylloblattidae = 'crown-Grylloblattida') and fossil species of the taxon concept Grylloblattida sensu Storozhenko (2002) is essentially based on postabdominal morphology. However, the fossil data are limited, and the interpretation is open to debate. Here we investigate a sample of a poorly known fossil 'grylloblattidan' family, the Bajanzhargalanidae, collected from the Daohugou locality (Middle Jurassic, China). We describe Sinonele fangi gen. nov., sp. nov., Sinonele hei gen. nov., sp. nov., Sinonele phasmoides gen. nov., sp. nov., and Sinonele mini gen. nov., sp. nov. Thanks to the abundance and exceptional preservation of the material, we could document wing venation intra-specific variability, provide cues to identify male and female individuals, describe and tentatively interpret various body structures of both sexes, and discuss them with a broad pterygotan phylogenetic perspective. The Bajanzhargalanidae exhibit a puzzling combination of postabdominal characters leaving us inconclusive on their affinities, or lack thereof, with crown-Grylloblattida. Our contribution suggests that a substantial effort will be needed to further investigate postabdominal structures from comparatively ancient fossil insects preserved as rock imprints, because of their broad morphological disparity.

The morphology of the eggs of three species of Zoraptera (Insecta)

The egg structure of Zorotypus magnicaudelli, Zorotypus hubbardi and Zorotypus impolitus was examined and described in detail. Major characteristics of zorapteran eggs previously reported were confirmed in these species, with the partial exception of Z. impolitus: 1) a pair of micropyles at the equator of the egg's ventral side, 2) a honeycomb pattern on the egg surface, 3) a two-layered chorion, 4) micropylar canals running laterally, 5) a flap covering the inner opening of the micropylar canal and 6) no region specialized for hatching. These features are probably part of the groundplan of the order. Three groups (A-C) and two subgroups (A1 and A2) of Zoraptera can be distinguished based on characters of the reproductive apparatus including eggs. However, information for more species is needed for a reliable interpretation of the complex and apparently fast evolving character system. The egg of Z. impolitus presumably shows apomorphic characteristics not occurring in other species, a chorion without layered construction and polygonal surface compartments with different sculptures on the dorsal and ventral sides of the egg. Another feature found in this species, distinct enlargement of the micropyles, is also found in Z. hubbardi. The increased micropylar size is likely correlated with the giant spermatozoa produced by males of these two species. These two features combined with the large size of the spermatheca are arguably a complex synapomorphy of Z. hubbardi and Z. impolitus. The phylogenetic placement of Zoraptera is discussed based on the egg structure. A clade of Zoraptera + Eukinolabia appears most plausible, but the issue remains an open question.

The sperm pump of the hangingfly Bittacus planus Cheng (Mecoptera: Bittacidae)

The males of antliophoran insects usually use a sperm pump to transfer liquid sperm into the reproductive tract of the female. However, the fine structure of the sperm pump and its ejaculatory mechanism has not been thoroughly clarified in many groups of Mecoptera. In this paper, the structure of the sperm pump was investigated in the hangingfly Bittacus planus Cheng, 1949 using light and scanning electron microscopy. The sperm pump mainly consists of a piston fused with a piston-carrying sclerite, a pumping chamber enclosed by the genital folds, which comprises the posterior region of the ejaculatory sac, an ostial sclerite, a phallobase, and other associated structures and muscles. The piston crown plays a major role in the piston movement. The ostial sclerite serves as a discharge valve and is controlled by two antagonistic muscles. No depressor muscles were found attached to the piston. The sperm pumping activity is mainly controlled by the combination of the levator of the piston and the retractor and protractor of the ostial sclerite. The ejaculatory mechanism and phylogenetic significance are briefly discussed based on the structure of the sperm pump.

Familial Clarification of Saucrosmylidae stat. nov. and New Saucrosmylids from Daohugou, China (Insecta, Neuroptera)

Backgound

Saucrosmylids are characterized by the typically large body size, complicated venation and diverse wing markings, which were only discovered in Middle Jurassic of Daohugou, Ningcheng county, Inner Mongolia, China.

Principal Findings

Saucrosmylinae Ren, 2003, originally included as a subfamily in the Osmylidae, was transferred and elevated to family rank based on the definitive synapomorphic character. The updated definition of Saucrosmylidae stat. nov. was outlined in detail: presence of nygma and trichosors; diverse markings on membrane; complicated cross-veins; distal fusion of Sc and R1; expanded space between R1 and Rs having 2–7 rows of cells that should be a synapomorphic character of the family; proximal MP fork. And the previous misuses of Saucrosmylidae are also clarified. Furthermore, a new genus with a new species and an indeterminate species of Saucrosmylidae are described as Ulrikezza aspoeckae gen. et sp. nov. and Ulrikezza sp. from the Middle Jurassic of Daohugou, Inner Mongolia, China. A key to genera of Saucrosmylidae is provided.

Conclusions/Significance

The intriguing group represents a particular lineage of Neuroptera in the Mesozoic Era. The familial status of Saucrosmylidae was firstly advanced that clarified the former incorrect citation and use of the family name. As an extinct clade, many species of the saucrosmylids were erected just based on a single fore- or hindwing, and it should be realized that providing more stable characters is necessary when describing new lacewing taxa just based on an isolated hindwing. It is vital for the systematics of Saucrosmylidae.

New records for the Kosovo caddisfly fauna with the description of a new species, Drusus dardanicus sp. nov. (Trichoptera: Limnephilidae)

The Balkan Peninsula is one of the most important European hotspots of freshwater biodiversity. The region is, however, to a large extent insufficiently investigated. Here we present data on distribution of caddisflies in one particularly understudied area, the Republic of Kosovo. Our data include the first records of Adicella altandroconia Botosaneanu & Novak and Halesus tessellatus (Rambur) for the Kosovo caddisfly fauna, and a new locality for the recently described Ecclisopteryx keroveci Previšić, Graf, & Vitecek. Further, we describe the new caddisfly species Drusus dardanicus sp. nov. from the Kopaonik Mountains. The new species belongs to the D. discophorus Species Group and differs morphologically from its most similar congeners (D. discophorus Radovanović, D. balcanicus Kumanski, and D. bureschi Kumanski) mainly in exhibiting (1) subtrianglar superior appendages; (2) a narrow, dorsal spinate area of tergite VIII; and (3) evenly rounded tips of intermediate appendages in caudal view. In phylogenetic analysis, D. dardanicus sp. nov. is well delineated and recovered as a sister taxon to D. osogovicus Kumanski, a species recorded from Bulgaria. The recent discovery of a new species and other rare or microendemic species presents important contributions to the knowledge on the rich freshwater biodiversity in Kosovo. These species face increasing anthropogenic pressure and threats to their conservation.

Curious Oviposition Behavior in Phyllium westwoodii (Phasmatodea: Phylliidae): Preliminary Observations

We report that in a leaf insect, Phyllium westwoodii Wood-Mason (Phasmatodea: Phylliidae), two differing apertures can be used for oviposition, the color of eggs being affected by which aperture is used. Eggs which are forcibly propelled from the internal space within the valvulae of the abdomen are brown, whereas white eggs emerge slowly from the opening between the eighth sternite and the valvulae, and are deposited close to the ventral surface of the female. This unusual oviposition system does not appear to have been previously reported in phasmatids or in other insects.