Recherches sur la phylogénie du genre Saga (Orthoptera: Tettigoniidae): données chromosomiques

L’analyse cytogénétique de quatre espèces européennes de Saginae, dont les caryotypes n’avaient jamais été étudiés, la ré-investigation de celui de Saga pedo (Pallas 1771), la prise en compte des données publiées, et le résultat d’investigations sur le terrain, permettent de proposer une reconstitution de leur phylogénie. Les caryotypes les plus ancestraux semblent être ceux de Saga ornata Burmeister 1839 et de Saga cappadocica Werner 1903, publiés antérieurement, dont tous les autosomes seraient acrocentriques. La fusion de deux paires de leurs chromosomes aboutirait aux caryotypes de Saga natoliae Serville 1839 et de Saga hellenica Kaltenbach 1967, comportant une paire de grands submétacentriques. Ces deux caryotypes se différencient par une inversion péricentrique touchant ces grands chromosomes, probablement chez S. natoliae. Saga campbelli Uvarov 1921 et Saga rammei Kaltenbach 1965, ont acquis une fusion chromosomique de plus et possèdent donc deux paires de grands submétacentriques. Le caryotype de S. rammei détient en plus une particularité de son hétérochromatine. Enfin, le caryotype de S. pedo est tétraploïde, probablement formé de la juxtaposition de deux génomes diploïdes par hybridation. La particularité de l’hétérochromatine de S. rammei se retrouve chez S. pedo sur deux chromosomes différents. Alors que l’on pourrait attendre des quadruplets ou des doublets de chromosomes, il existe une grande diversité de chromosomes en copie unique. Ceci démontre qu’un fort taux de remaniements chromosomiques a modifié le caryotype de S. pedo, postérieurement à son passage à la tétraploïdie. Cette accumulation de remaniements, aboutissant à une forte hétérozygotie, peut s’expliquer par l’absence de filtre méiotique chez cette espèce parthénogénétique. Nos dernières prospections terrain dans le sud des Balkans, nous ont amené à découvrir une zone probable d’intergradation entre Saga pedo et certains taxons sexués affines. L’analyse chromosomique des individus de cette région va sans doute se révéler d’une importance essentielle pour la poursuite de nos recherches.     

Are solitary and gregarious Mormon crickets (Anabrus simplex, Orthoptera, Tettigoniidae) genetically distinct?

Phase polyphenisms are usually thought to reflect plastic responses of species, independent of genetic differences; however, phase differences could correlate with genetic differentiation for various reasons. Mormon crickets appear to occur in two phases that differ in morphology and behaviour. Solitary individuals are cryptic and sedentary whereas gregarious individuals form bands, migrate, and are aposematically coloured. These traits have been thought to be phenotypically plastic and induced by environmental conditions. However, there has been no previous investigation of the extent of genetic differences between solitary and gregarious populations of this widespread North American species. We sequenced two mitochondrial genes, COII and COIII, in samples of Mormon crickets from gregarious populations west of the continental divide and solitary mountain populations primarily east of the divide. Sequencing revealed two genetically distinct clades that broadly correspond with the solitary eastern populations and the mainly gregarious western populations. We used coalescent modelling to test the hypothesis that the species consists of two deep genetic clades, as opposed to a series of equally distinct populations. Results allowed us to reject the null hypothesis that a radiation independent of phase produced these clades, and molecular clock estimates indicate the time of divergence to be approximately 2 million years ago. This work establishes that the solitary populations found in the mountains on the eastern slope are part of a clade that is genetically distinct from the western populations, which are primarily gregarious, and the implications of this apparent correlation between phase and genetic differentiation are discussed.     

New genus of leaf-mimicking katydids (Orthoptera: Tettigoniidae) from the Late Eocene–Early Oligocene of France and England

A new leaf-mimicking katydid (Orthoptera: Tettigoniidae: Pseudophyllinae), Archepseudophylla fossilis gen. et sp. nov. is described based on tegmina from the Early Oligocene of France. Lithymnetes laurenti Théobald, 1937 from the Late Eocene of France is transferred to Archepseudophylla comb. nov. The enigmatic ‘Poekilloptera’ melanospila Cockerell, 1921 from the Early Oligocene of the Isle of Wight (UK) is transferred to Archepseudophylla comb. nov. The present discoveries in the Palaeogene of the Isle of Wight, Céreste, and Marseilles Basins represent the first fossil records of Pseudophyllinae. In addition, these records support warm and humid forest conditions near the palaeolakes of the Isle of Wight, Camoins-les-Bains, and Céreste.     

La contraception masculine ? verte ?: mythe ou réalité ?

Rejection of ??chemical?? solutions, often considered as suspicious, is leading an increasing number of people to investigate natural alternatives whenever they find them. The field of medicine ?? and more specifically that concerning reproduction-is not exempt of that endeavour, which dates back thousands of years. It also has financial implications in countries where access to medication is problematic, if not impossible. Male contraception is not forgotten in this context; in particular in emerging countries, where a high birth rate has a negative impact on society. The main active plant extracts have been ?? and still are ?? the subject of very focused research. There is strong evidence to suggest that there are solutions which exist in this area. In vivo animal tests (on the whole), but also in vitro tests on isolated spermatozoa have highlighted the existence of significant central, peripheral and spermicidal effects. When being used systemically, care must always be taken to ensure that the often multiple therapeutic qualities of the plants concerned do not result in undesirable side effects from the contraceptive effect sought.     

Étude comparée de Saga rhodiensis Salfi 1929 et Saga natoliae Serville 1839 (Orthoptera: Tettigoniidae)

Saga rhodiensis se révèle très proche de S. natoliae et ces deux taxons s’acceptent mutuellement pour la copulation. En outre, ils constituent, avec S. hellenica, un groupe assez homogène au niveau chromosomique. Sur le plan morphologique S. hellenica se distingue aisément des deux autres espèces, et aucun accouplement croisé n’a pu aboutir dans nos élevages. La découverte d’individus femelles de S. natoliae présentant les critères morphologiques de S. rhodiensis bien audelà de l’aire de distribution actuellement connue, nous interroge sur la pertinence de ces critères. Des investigations complémentaires sont nécessaires pour préciser le statut exact de S. rhodiensis.     

Population dynamics in the Grey Bush Cricket Platycleis albopunctata (Orthoptera: Tettigoniidae) – What causes interpopulation differences?

We found sharply differing population dynamics in Platycleis albopunctata at two one-hectare study sites differing in vegetation cover and inclination of slopes. At one site, the population remained relatively constant (about 600 individuals) over the period observed, while at the other site the population size varied during the observation period between more than 3000 and less than 100 individuals. This field observation was analysed by an experimental study of embryonic development and reproduction, both of which are expected to largely influence population dynamics. These experiments revealed a close correlation between the temperature and the duration of egg development on the one hand and fecundity on the other. We concluded that the temperature dependence of development and reproduction is responsible for the weather dependence of population dynamics. Based on our results, we developed a hypothesis to explain the striking differences in the dynamics of the two study sites which attributes them to differences in microclimate and primary production. Additionally, we applied a simulation model to investigate the weather dependence of the population dynamics. Finally, we discuss the consequences of different population dynamics for conservation: (a) the example stresses the difficulties that arise when using demographic data of any population for the prognosis of the extinction risk of a population under study; (b) the dependence of population dynamics on habitat parameters means they can be influenced by management.     

Diel Calling Activity and Field Survival of the Bushcricket,Sciarasaga quadrata (Orthoptera: Tettigoniidae): A Role for Sound-locating Parasitic Flies?

In this study I examine the variability in calling activity of Sciarasaga quadrata over both the short (4 d) and long term (life span), and the temporal pattern to host searching by its most significant natural enemy, the ormiine fly Homotrixa alleni. Indeed, few male S. quadrata survive the entire calling season as this acoustically orienting parasitoid fly continually ‘culls’ calling males out of the population. I found that male S. quadrata commence calling over 1 h before sunset, cease around midnight and call, on average, for over 3 h within this period (range 0–11 h 09 min). There was significant concordance and repeatability in calling activity over both the short and long term, enabling me to conclude that relative differences in calling activity among males persist throughout a male's life span. There was a distinct peak to host searching by gravid female flies, with 82 % of all flies collected at acoustic traps between sunset and midnight. A positive association between call duration (time spent calling) and fly attraction was evident from multiple collections of flies at single traps. Counter to expectation, there was no significant decline in average call duration across successive collections of males, indicating that long-call-duration males were not being selectively culled by flies from the calling population. Males at the end of the calling season, when their remaining reproductive potential is low, allocate the majority of their calling time between sunset and midnight despite the high risk of fly attack. The distribution of call durations within the population was not skewed, which if heritable, indicates a lack of history of directional selection acting on call duration. Limited evidence suggests that encounters with females are rare in S. quadrata so that males may be selected, irrespective of natural selection pressure, to call for long periods of time to optimize their chance of attracting mates. The above findings are further discussed in relation to parasitoid foraging and acoustic reproductive strategies.     

Effects of mating status on copulation investment by male bushcricket Gampsocleis gratiosa (Tettigoniidae, Orthoptera)

In many insect species, male will donate prey, se-cretion, and spermatophore as “nuptial gift” or “court- ship feeding” to females prior to, after or during the copulation[1,2]. The nuptial gifts represented great re-productive cost. In bushcrickets, …     

La denture et la région palatine des placodontia (Reptilia,Trias).Implications phylogénétiques

Dental and palatal anatomies of the valid taxa of the Placodontia (Reptilia, Triassic) are described. This analysis leads to a synthesis of the different dental and palatal structures, and to an evolutionary model of acquisition of the particular placodontian dentition, from a general reptilian one. A phylogeny and a classification of the Placodontia, mainly based on these dental and palatal characters, are deduced from it.     

The first fossil spider cricket (Orthoptera: Gryllidae: Phalangopsinae): 20 million years of troglobiomorphosis or exaptation in the dark?

A new spider cricket (Orthoptera: Gryllidae: Phalangopsinae) is described from an adult female preserved in Early Miocene (Burdigalian) amber from the Dominican Republic. Araneagryllus dylani gen. et sp. nov. represents the first fossil record of Phalangopsinae, and is assigned to the tribe Luzarini, subtribe Amphiacustina stat. nov. A cladistic analysis of Amphiacustina places Araneagryllus gen. nov. within a clade comprising Arachnopsita, Leptopedetes, Longuripes, Mayagryllus, Nemoricantor, and Prolonguripes. This clade is the sister group to a clade comprising Amphiacusta, Cantrallia, and Noctivox. The results of this analysis suggest that: (1) the common ancestor of all Amphiacustina was epigean, and was likely to have been cavicolous and/or straminicolous; (2) strict troglobitism evolved twice within Amphiacustina, once in the lineage leading to Noctivox and again in the clade comprising Mayagryllus, Arachnopsita, Longuripes, and Prolonguripes; and (3) Prolonguripes is secondarily epigean, having reverted to life above ground. The occurrence of Araneagryllus gen. nov. in amber indicates that it was not troglobitic, but was instead more likely to have been straminicolous, living on the ground and foraging amongst leaf litter. Araneagryllus gen. nov. possesses a number of characters that are usually considered to be adaptive to a troglobitic life history, suggesting that many so‐called troglobiomorphies are not adaptations to life in caves, but are instead likely to have been exaptive. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 158 , 56–65.     

Géométrie morphologique des ailes des Acrididae (Orthoptera : Caelifera) : sexe,stridulation, caractère

La nervation des élytres d’Acrididae de la région ouest paléarctique a été étudiée au moyen de 2 méthodes de morphométrie de manière à faire ressortir les caractères adaptatifs relatifs à la stridulation et les marqueurs de phylogénie. Huit Points de Repère (PR) situés dans la région proximale des élytres, incluant le champ médian, ont été considérés pour l’analyse de morphométrie géométrique. L’importance relative des champs a été appréhendée par ACP. Il apparaît que le dimorphisme sexuel des PR caractérise les espèces à stridulation de forte intensité chez le mâle (Gomphocerinae et Stethophyma grossum). Les mâles présentent par rapport aux femelles un élargissement des champs sous-costaux antérieur et postérieur, et du champ radial, lié à un déplacement distal de la bifurcation entre les radiales antérieure et postérieure, ce qui entraîne un élargissement de la surface de résonance. L’élargissement du champ cubital antérieur est une déformation propre à la tribu des Locustini et n’a pas de valeur adaptative apparente.     

Les petits ongulés de la grotte acheuléano-moustérienne du Lazaret (Nice,France) – Origine anthropique ou carnivore ?

Lazaret Cave contains archaeological deposits contemporaneous with Acheulean and Mousterian cultures, corresponding to marine isotopic stage 6 (MIS 6). Archaeological excavations at the site revealed twenty-nine archaeostratigraphic units with recurring, relatively long occupations by Homo heidelbergensis groups. These groups preferentially hunted red deer and ibex, which were abundant in all the units. In contrast, other species, such as the chamois and the roe deer, are poorly represented. In this article, we present the results of the archaeozoological and taphonomic analyses of small ungulate bones in order to determine how these remains were deposited in the cave. Opportunistic anthropogenic hunting is brought to light in some units, explaining the low proportion of these species at the site. In addition, these species only provide low nutrient levels for the needs of the group. The accumulation of remains by carnivores is also observed, mainly by the wolf, which is abundant in the upper units.     

Cytogenetics studies in Brazilian species of Pseudophyllinae (Orthoptera: Tettigoniidae): 2n(♂)=35 and fn=35 the probable basic and ancestral karyotype of the family Tettigoniidae

The karyotypes of five species of Brazilian Pseudophyllinae belonging to four tribes were here studied. The data available in the literature altogether with those obtained with species in here studied allowed us to infer that 2n(♂)=35 is the highest chromosome number found in the family Tettigoniidae and that it is present in species belonging to Pseudophyllinae, Zaprochilinae and in one species of Tettigoniinae. In spite of that all five species exhibit secondary karyotypes arisen surely by a mechanism of chromosomal rearrangement of centric fusion, tandem fusion and centric inversion types from those with 2n(♂)=35 and FN=35, they share some common traits. The X chromosome is submetacentric (FN=36), heteropicnotic during the first prophase, the largest of the set but its size is rather variable among the species and the sex chromosomal mechanism is of the XO( ♂ ), XX( ♀ ) type. The chromosomal rearrangements involved in the karyotype evolution of the Pseudophyllinae and its relationship with those of the family Tettigoniidae are discussed and we propose that the basic and the ancestral karyotype of the Tettigoniidae is formed by 2n(♂)=35, FN=35 and not by 2n(♂)=31, FN= 31, as usually accepted.     

La hache de Laplume (Lot-et-Garonne) : un outil en pierre polie parmi les plus importants du Néolithique du Midi de la France

This polished axe has been discovered formerly at Laplume (Lot-et-Garonne) but the definite location and the archaeological context are unknown. With regard to its large dimensions and particularly its exceptional weight (1510.8 g), this axe is one of the most important polished tools for the Neolithic period in Southern France.     

Platycleis vittata (Orthoptera: Tettigoniidae) in the northwestern part of its range is close to extinction: is this the result of landscape changes?

The northwestern distributions of several steppe species of Orthoptera extend to the southeastern part of the Czech Republic (Pannonia) and occupy more or less isolated fragments of optimal habitats. Their distributional limits are not conditioned by macroclimate in most cases but reflect landscape development (physical structure, plant community type and microclimate) and the insects’ dispersal abilities. These species prefer permanent grassland, and assessment of land use records indicates that the area occupied by permanent grassland has been greatly reduced by agriculture over the last two centuries. The area occupied by permanent grasslands in Pannonia was highest in the nineteenth century, declined until the second half of the twentieth century, and slightly increased at the beginning of the twenty first century. These changes in the area of permanent grassland generally reflect economic and political processes; in particular, consolidation of land plots and expropriation of private property brought an end to grazing. The distribution of a model Orthoptera specialist, Platycleis vittata, on steppe habitats was surveyed at 48 potentially suitable locations from 2004 to 2010. The survey determined that the area with suitable habitat is currently very limited at all 48 locations. Occurrence was confirmed in just two locations that are 3 km apart. The research suggests that Platycleis vittata in the Czech Republic is on the brink of extinction because of extreme fragmentation of suitable biotopes and degradation of optimal habitats.     

Le plus vieil établissement de métallurgistes de France (IIIe millénaire av. J.-C.) : Péret (Hérault)

The settlement of Chalcolithic metalworkers of La Capitelle du Broum is a truly outstanding site. The first AMS ¹⁴C dating (3rd millennium BC) reveals it as the oldest site in the mining and metallurgy district of Cabrières. It is of the same age as the oldest metallurgy site discovered in continental France (Roquemengarde). It includes, near the prehistoric copper mines already discovered, double-facing dry-stone walls of the Fontbouisse type and a variety of metallurgy structures. Metalworking tools, including one of the very rare ingot crucibles known from this period in Western Europe, are found alongside ceramics typical of the Late Neolithic (Broum type?). To cite this article: P. Ambert et al., C. R. Palevol 1 (2002) 67–74.     

Une faune inédite de coraux scléractiniaires dans le gisement chattien d'Escornebéou (Landes,SW France) ; stratigraphie,systématique et paléoécologie

The Escornebéou locality (Landes, SW Aquitaine Basin) is a reference site for the marine Chattian of atlantic tropical type. The abundant microorganisms allowed these outcrops to be allocated to the classic biozonations, after numerous historical controversies about their age. A fauna of Scleractinian corals has been discovered there for the first time, mainly from the ‘Le Bois’ site. About 25 taxa are listed and their systematics is analysed. They split up into 18 genera and subgenera, with stratigraphically a cachet intermediate between the Oligocene and Miocene faunas. There are as many solitary species as colonial ones (mainly hermatypics). The presence of numerous reefal genera confirms the tropical (to subtropical) paleoclimate, as well as the data from the other present organisms. Concerning the coarse zoogene calcareous deposits from ‘Le Bois’ (where the coral colonies are massive), the environment was shallow, fairly turbulent and under the effect of currents and waves. A subreefal facies locally developed (with mixed hermatypic and ahermatypic corals), belonging to the paleogeographic domain of shoal-type or barrier-type bioclastic limestones, as recognized elsewhere. At Escornebéou, the outcropping sequence is mainly marly to fine-grained sandy-marly (including such coarse calcareous intercalations), as at Lespeyrères, where few corals have also been found. These calm environments, of sheltered marine mud flat or seaweed type, were not very favourable to coral growth.     

Un Mésosuchien ziphodonte dans l'Éocène supérieurde La Livinière (Hérault,France)

Crocodilian remains collected at the turn of the centuryin the early Bartonian locality of La Livinière (Hérault, southern France) belong to a ziphodont mesosuchian. They include compressed, serrated teeth, primitive jugals, amphicoelous vertebrae, dermal scutes, and elongated, slender limb bones. The systematic position of this animal is difficult to determine, but it is more reminiscent of some forms from the upper Cretaceous of South America than of the Tertiary Sebecidae. It may be related to Iberosuchus, a ziphodont mesosuchian from the Eocene of the Iberian peninsula. Its peculiar limb bones confirm the terrestrial habits of ziphodont crocodilians.