Redefining the extinct orders Miomoptera and Hypoperlida as stem acercarian insects.

BACKGROUND: The systematic positions of the extinct insect orders Hypoperlida, Miomoptera and Permopsocida were enigmatic and unstable for nearly a century. The recent studies based on new material, especially from the Cenomanian Burmese amber, shed light on evolutionary history of Acercaria resolving Permopsocida as the stem group of Condylognatha. However, the knowledge of the remaining two orders differs significantly. RESULTS: In this study, we describe new specimens and evaluate morphology of various structures with emphasis on the mouthparts and wing venation. Our results are primary based on revisions of the type specimens with a proper delimitation of taxa Hypoperlida and Miomoptera followed by their significance for the evolutionary history of Acercaria. Three new genera as Belmomantis gen. nov., Elmomantis gen. nov., and Mazonopsocus gen. nov. are designated as members of Palaeomanteidae. The Pennsylvanian Mazonopsocus provides a minimum age for calibration, in accordance to the presence of crown acercarians during the late Carboniferous. CONCLUSIONS: This contribution demonstrates that Hypoperlida and Miomoptera are stem groups of Acercaria. The putative clade (Hypoperlida + Miomoptera) is appearing as potential sister group of (Psocodea + (Permopsocida + (Thripida + Hemiptera))).

Laying the foundations of evolutionary and systematic studies in crickets (Insecta, Orthoptera): a multilocus phylogenetic analysis.

Orthoptera have been used for decades for numerous evolutionary questions but several of its constituent groups, notably crickets, still suffer from a lack of a robust phylogenetic hypothesis. We propose the first phylogenetic hypothesis for the evolution of crickets sensu lato, based on analysis of 205 species, representing 88% of the subfamilies and 71% tribes currently listed in the database Orthoptera Species File (OSF). We reconstructed parsimony, maximum likelihood and Bayesian phylogenies using fragments of 18S, 28SA, 28SD, H3, 12S, 16S, and cytb (~3600 bp). Our results support the monophyly of the cricket clade, and its subdivision into two clades: mole crickets and ant-loving crickets on the one hand, and all the other crickets on the other (i.e. crickets sensu stricto). Crickets sensu stricto form seven monophyletic clades, which support part of the OSF families, "subfamily groups", or subfamilies: the mole crickets (OSF Gryllotalpidae), the scaly crickets (OSF Mogoplistidae), and the true crickets (OSF Gryllidae) are recovered as monophyletic. Among the 22 sampled subfamilies, only six are monophyletic: Gryllotalpinae, Trigonidiinae, Pteroplistinae, Euscyrtinae, Oecanthinae, and Phaloriinae. Most of the 37 tribes sampled are para- or polyphyletic. We propose the best-supported clades as backbones for future definitions of familial groups, validating some taxonomic hypotheses proposed in the past. These clades fit variously with the morphological characters used today to identify crickets. Our study emphasizes the utility of a classificatory system that accommodates diagnostic characters and monophyletic units of evolution. Moreover, the phylogenetic hypotheses proposed by the present study open new perspectives for further evolutionary research, especially on acoustic communication and biogeography.

Inside the Melanoplinae: new molecular evidence for the evolutionary history of the Eurasian Podismini (Orthoptera: Acrididae).

The Podismini are melanopline grasshoppers with a Holarctic distribution and well represented in the Eurasian fauna. To investigate their controversial taxonomy and evolutionary history, we studied 86%, 78% and 33% respectively of the Eurasian, European and Asian Palaearctic genera (Otte, 1995; Eades et al., 2013). We reconstructed parsimony, maximum likelihood and Bayesian phylogenies using fragments of four genes (ITS1, 16S, 12S, CO2). We applied a Bayesian molecular clock to estimate the times of species divergence, and the event-based parsimony method to depict the biogeographic framework of the diversification. Our results suggest that the selected Eurasian Podismini constitute a monophyletic group inside the Melanoplinae, provided it includes the North American genus Phaulotettix. The clades proposed by the present study inside the Podismini do not fit the older morphological or cytological classifications, but are in agreement with more recent proposals. Furthermore, our results can be explained by a plausible biogeographic history in which the present geographical distribution of the Eurasian Podismini resulted from known changes, to the Cenozoic climate and vegetation, induced by major geological events including the genesis of high mountain chains (e.g., Himalayas, Altay, Alps) and large deserts (e.g., Gobi, Karakoum, Taklamakan), and the opening of marginal seas (e.g., Bering, Japanese and Yellow Seas).

Evolutionary history and taxonomy of a short-horned grasshopper subfamily: the Melanoplinae (Orthoptera: Acrididae).

The Melanoplinae is one of the largest subfamilies of the Acrididae grasshoppers, with a Holarctic-Neotropical distribution. To investigate its controversial taxonomy and evolutionary history, we studied 19 species representative of its main tribes, and 7 Acridoidea outgroup species. More than 1650 base pairs of three regions of nuclear rDNA (18S, ITS1, 28S) and one mitochondrial rDNA (12S) were combined and used to construct parsimony, maximum likelihood and Bayesian phylogenies. Our results correspond with the present geographical distribution of the taxa rather than the existing taxonomy based on morphological characters. The morphologically unclassified and atypical taxa group with the Neotropical Melanoplinae. The currently recognized Melanoplinae appear to be polyphyletic due to inclusion of the Mexican genus Netrosoma. The distribution of the American and Eurasiatic Melanoplinae fauna can be explained by climatic and geological events, such as the Andean uplift, that would have affected the diversification and migration of Neotropical taxa.

Evolution and taxonomy of the wild species of the genus Ovis (Mammalia, Artiodactyla, Bovidae).

New insights for the systematic and evolution of the wild sheep are provided by molecular phylogenies inferred from Maximum parsimony, Bayesian, Maximum likelihood, and Neighbor-Joining methods. The phylogeny of the wild sheep was based on cytochrome b sequences of 290 samples representative of most of the sub-species described in the genus Ovis. The result was confirmed by a combined tree based on cytochrome b and nuclear sequences for 79 Ovis samples representative of the robust clades established with mitochondrial data. Urial and mouflon, which are either considered as a single or two separate species, form two monophyletic groups (O. orientalis and O. vignei). Their hybrids appear in one or the other group, independently from their geographic origin. The European mouflon O. musimon is clearly in the O. orientalis clade. The others species, O. dalli, O. canadensis, O. nivicola, and O. ammon are monophyletic. The results support an Asiatic origin of the genus Ovis, followed by a migration to North America through North-Eastern Asia and the Bering Strait and a diversification of the genus in Eurasia less than 3 million years ago. Our results show that the evolution of the genus Ovis is a striking example of successive speciation events occurring along the migration routes propagating from the ancestral area.

New insights on basivenal sclerites using 3D tools and homology of wing veins in Odonatoptera (Insecta).

Being implied in flight, mimetism, communication, and protection, the insect wings were crucial organs for the mega diversification of this clade. Despite several attempts, the problem of wing evolution remains unresolved because the basal parts of the veins essential for vein identification are hidden in the basivenal sclerites. The homologies between wing characters thus cannot be accurately verified, while they are of primary importance to solve long-standing problems, such as the monophyly of the Palaeoptera, viz. Odonatoptera, Panephemeroptera, and Palaeozoic Palaeodictyopterida mainly known by their wings. Hitherto the tools to homologize venation were suffering several cases of exceptions, rendering them unreliable. Here we reconstruct the odonatopteran venation using fossils and a new 3D imaging tool, resulting congruent with the concept of Riek and Kukalová-Peck, with important novelties, viz. median anterior vein fused to radius and radius posterior nearly as convex as radius anterior (putative synapomorphies of Odonatoptera); subcostal anterior (ScA) fused to costal vein and most basal primary antenodal crossvein being a modified posterior branch of ScA (putative synapomorphies of Palaeoptera). These findings may reveal critical for future analyses of the relationships between fossil and extant Palaeoptera, helping to solve the evolutionary history of the insects as a whole.

Ribosomal DNA in the grasshopper Podisma pedestris: escape from concerted evolution.

Eukaryote nuclear ribosomal DNA (rDNA) typically exhibits strong concerted evolution: a pattern in which several hundred rDNA sequences within any one species show little or no genetic diversity, whereas the sequences of different species diverge. We report a markedly different pattern in the genome of the grasshopper Podisma pedestris. Single individuals contain several highly divergent ribosomal DNA groups. Analysis of the magnitude of divergence indicates that these groups have coexisted in the Podisma lineage for at least 11 million years. There are two putatively functional groups, each estimated to be at least 4 million years old, and several pseudogene groups, many of which are transcribed. Southern hybridization and real-time PCR experiments show that only one of the putatively functional types occurs at high copy number. However, this group is scarcely amplified under standard PCR conditions, which means that phylogenetic inference on the basis of standard PCR would be severely distorted. The analysis suggests that concerted evolution has been remarkably ineffective in P. pedestris. We propose that this outcome may be related to the species' exceptionally large genome and the associated low rate of deletion per base pair, which may allow pseudogenes to persist.

Complete mitochondrial genome and taxonomic revision of Cardiodactylus muiri Otte, 2007 (Gryllidae: Eneopterinae: Lebinthini).

In the present study, we report the high-coverage complete mitochondrial genome (mitogenome) of the cricket Cardiodactylus muiri Otte, 2007. The mitogenome was sequenced using a long-PCR approach on an Ion Torrent Personal Genome Machine (PGM) for next generation sequencing technology. The total length of the amplified mitogenome is 16,328 bp, representing 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes and one noncoding region (D-loop region). The new sets of long-PCR primers reported here are invaluable resources for future comparative evolutionary genomic studies in Orthopteran insects. The new mitogenome sequence is compared with published cricket mitogenomes. In the taxonomic part, we present new records for the species and describe life-history traits, habitat and male calling song of the species; based on observation of new material, the species Cardiodactylus buru Gorochov & Robillard, 2014 is synonymized under C. muiri.

3-D imaging reveals four extraordinary cases of convergent evolution of acoustic communication in crickets and allies (Insecta).

When the same complex trait is exhibited by closely related species, a single evolutionary origin is frequently invoked. The complex stridulatory apparatus present in the forewings of extant crickets, mole crickets, katydids, and prophalangopsids, is currently interpreted as sharing a single common origin due to their similarity and unique function. An alternative hypothesis of convergent evolution in these ensiferan groups has challenged this common view, but remained controversial because of competing interpretations of wing venation. Here we propose another hypothesis for the widely and long debated homology of ensiferan stridulatory apparatus, performing the first 3D reconstruction of hidden structures at the wing bases. This approach allowed defining the homology of each vein from its very origin rather than after its more distal characteristics, which may be subjected to environmental pressure of selection. The stridulatory apparatus involves different veins in these four singing clades. In light of the most recent phylogenetic evidence, this apparatus developed four times in Ensifera, illustrating extraordinary convergent evolutions between closely related clades, by far exceeding the number of evolutionary steps ever proposed for calling ability in this group.

[Selectivity and environmental variations in herbivory by Orthoptera]. / Sélectivité et variations environnementales de l'herbivorie par les Orthoptères.

The aim of this study is 1 degree) to quantify environmental changes in herbivory due to Orthoptera on two perennial grasses and 2 degrees) to assess the processes involved in the control of herbivory. Herbivory varies strongly according to shade, drought and mowing, and is positively related to vapour pressure deficit and temperature. Besides the hypothesis of a trophic control of herbivory, our results are consistent with a microclimatic control of herbivory by Orthoptera. The coexistence of different hypothesis of herbivory control may depend on the studied system and specifically on the type of herbivore involved.