Feeding patterns of the aquatic grasshopper Cornops aquaticum (Bruner) (Orthoptera: Acrididae) in the middle Paraná river, Argentina

The aquatic grasshopper Cornops aquaticum (Bruner) is native to South America and inhabits lowlands from southern Mexico to Central Argentina and Uruguay. This grasshopper is host-specific to aquatic plants of the genera Eichhornia and Pontederia. The objectives of this study were to analyze the feeding patterns of the aquatic grasshopper C. aquaticum in relationship to development stages and sex and to determine the food consumption rate in their host plant, Eichhornia crassipes. Samples were collected from April 2006 to May 2007 in different floodplain lakes of the Middle Parana River. The average consumption was greater in the females (0.127 g food/day ± 0.051) than in the males (0.060 g food/day ± 0.025). The feces of 361 nymphs and adults of this locust were examined and the most common tissue fragments found were of the water hyacinth (E. crassipes). In the initial nymphal stages (I, II and III), an exclusive consumption of E. crassipes was registered, while in the IV and V stages the choice included also other macrophytes. In summary, C. aquaticum presents polyphagy in the field, feeding on six macrophytes of different classes and families.     

Discrepancies between subgeneric classification and molecular phylogeny of Ceratitis (Diptera: Tephritidae), can the evolution of host use provide some clues?

Using molecular data from three protein encoding genes and 49 taxa (98 specimens from 20 African countries), we provide an extended phylogeny of Ceratitis and investigate the evolution of stenophagy across clades. Bayesian tree reconstructions support previously proposed monophyletic lineages (Pardalaspis, Pterandrus section A, Pterandrus section B+Ceratitis sensu stricto) and reveal the occurrence of two new monophyletic groups including Ceratalaspis/Hoplolophomyia (viz. Cl(A), and Cl(B)+H). The reconstruction of ancestral character states shows that stenophagy evolved repeatedly and independently in five different clades (Podocarpus, Solanum, Strychnos, Tabernaemontana and Vepris feeders). The evolution of feeding preferences is closely related to the phylogenetic patterns of Ceratalaspis/Hoplolophomyia whose sections include either polyphagous species (Cl(A)) or stenophagous taxa (Cl(B)+H) that are further subdivided in Vepris and Solanum feeders. The evolution of stenophagy in the genus Ceratits appears as the result of a process leading to the exploitation of "unconventional" fruits (viz. toxic and/or not fleshy) and involving either metabolic adaptation to toxic plant compounds and/or the capability of penetrating fruits with thick cuticles.     

On the origin of the desert locust Schistocerca gregaria (Forskål) (Orthoptera: Acrididae: Cyrtacanthacridinae)

The locust genus Schistocerca (Stål) has a transatlantic disjunction, which has been controversial for more than a century. Among 50 species within the genus, only one species, the desert locust (S. gregaria Forskål), occurs in the Old World, and the rest occur in the New World. Earlier taxonomists suggested that the desert locust is a migrant from America, but this view was strongly challenged when a large swarm of the desert locust successfully crossed the Atlantic Ocean from West Africa to the West Indies in 1988. The currently accepted view, supported by this incident, is that the New World species are descendants of a gregaria-like ancestor, and the desert locust would be ancestral to the rest of the genus. However, there is surprisingly little evidence to support this view other than the 1988 swarm. I present the most comprehensive phylogenetic study that suggests that the desert locust originated from the New World, contrary to the accepted view. I also present a hypothesis about how the ancestral Schistocerca might have colonized the New World in the first place in light of phylogenetic relationships with other cyrtacanthacridine genera.     

Glandular pouches of the genital chamber of female Schistocerca gregaria (Forskål) (Orthoptera : Acrididae)

Females of the desert locust, Schistocerca gregaria, have a pair of conspicuous glandular pouches associated with the genital chamber and gonoducts. Each pouch consists of a cuticular sac with an epithelium comprising at least 3 types of cells, namely epidermal cells, vacuolated secretory cells, and duct cells. The vacuole of each secretory cell is connected to the cavity of the pouch by a long, convoluted, cuticular duct some 1 μm in diameter, which runs through the cuticle. Each duct has an accompanying duct cell closely situated. The cuticle is perforated also by numerous fine ducts that do not extend into the epithelium: these appear to be large pore canals. Plates of secretion with a wax-like appearance are found in some pouch cavities, often forming close replicas of the latter. All the major features mentioned above are found in females with undeveloped ovaries as well as those with mature oöcytes: the pouches show little alteration in structure with advancing maturity. The nature of the pouches is compared with that of other Acrididae, and their functions are discussed.     

The phylogeny and evolution of thePterygodium—Corycium complex (Coryciinae,Orchidaceae)

The leaf-anatomy, palynology, seed-morphology, vegetative morphology and especially the highly complicated floral morphology of theCoryciinae s. str. (Diseae: Orchidoideae: Orchidaceae) are described and illustrated in detail. On the basis of these characters the presumed phylogeny, based on a rigorous cladistic analysis, is presented. The cladistic biogeographical analysis of theCoryciinae s. str. shows that it is a member of the Afrotemperate Track, with a pattern of vicariance events typical of the members of this track. An analysis of the patterns of speciation shows that allopatric speciation appears to be rare, and that parapatric speciation across edaphic boundaries may be the most important factor. Proceeding from the information presented, a new classification of the group is proposed in which we recognize the four generaCeratandra, Evotella, Pterygodium andCorycium. The new monotypic genusEvotella comprises a species originally described asPterygodium rubiginosum. The three species of the genusAnochilus are transferred toCorycium andPterygodium. P. magnum, which was originally described asPterygodium but was transferred toCorycium lately, is placed in a monotypic section ofPterygodium.     

Chromosome aberrations and response to γ-ray challenge in lymphocytes of workers exposed to 1,3-butadiene

An integrated population monitoring study was initiated to investigate whether occupational exposure to current low levels of butadiene is mutagenic to workers. Ten exposed workers (mean production area concentration of 3.5 ppm) and 10 matched plant controls(mean exposure to 0.03 ppm) were selected and blood samples were collected for our study. The standard cytogenetic assay was used to determine chromosome aberration frequencies. In addition, a challenge assay was used to determine response to γ-rays as an indication of DNA repair deficiencies. In the latter assay, cells were exposed to γ-rays at the G1 phase of the cell cycle in vitro and the frequencies of chromosome aberrations in the first post-irradiation metaphase cells were quantitated. Based on results of the cytogenetic assay, the exposed group had a higher frequency of cells with chromosome aberrations and higher chromatid breaks per 100 cells compared with the control. However, the difference was not significant (p > 0.1). With the challenge assay, the exposed group had a higher frequency of aberrant cells (p < 0.04), chromatid breaks (p < 0.05), deletions (p < 0.07), and dicentrics (p < 0.02) than the controls. In addition, the dicentric frequencies from workers were significantly correlated with the presence of a butadiene metabolite [1,2-dihydroxy-4-(N-acetyl-cysteinyl-S)butane] in urine with a correlation of coefficient of 0.6 (p < 0.01). Two outliers were identified and our interpretation of their responses will be discussed. This study indicates that the workers had exposure-induced mutagenic effects. Together with the observation of gene mutation in a subset of the present population, this study indicates that the current occupational exposure to butadiene may not be safe to workers.     

Redescription and revision of the Neotropical genus Pseudoheptascelio Szabó (Hymenoptera, Platygastridae, Scelioninae), parasitoids of eggs of short-horned grasshoppers (Orthoptera, Acrididae)

The genus Pseudoheptascelio Szabó is redescribed and its species revised. We recognize four species: Pseudoheptascelio muesebecki Szabó, Pseudoheptascelio cornopis Masner, Pseudoheptascelio ticosp. n. and Pseudoheptascelio rexsp. n. The genus is found from Guatemala south to the Brazilian state of Rio Grande do Sul. The species Pseudoheptascelio cornopis is recorded as a parasitoid of the eggs of Cornops aquaticum (Bruner) on water hyacinth, Eichhornia crassipes (Mart.) Solms.     

Animal phylogeny: back to the coelomata?

The relationship between vertebrates and the principal model invertebrates - fruitflies and nematodes - is unclear. A fly-nematode grouping was becoming widely accepted, but recent comparisons of their genomes argue against this and link flies with the vertebrates instead.     

Central Saharan populations of Locusta migratoria cinerascens (Orthoptera: Acrididae) in irrigated perimeters: is it a recent colonisation event?

Locusta migratoria cinerascens became a potential pest in irrigated cereals under pivots, in the Touat region (Algerian Central Sahara), since the indication of the first crowding in June 1994. Morphometrics and bioclimatic approaches revealed the homogeneity between North and South Algerian populations, suggesting a recent colonisation of Central Sahara, aided by the development of large acreage perimeters. We studied the populations of this acridian from 1995 to 2004 and show that they belonged to the solitarious or transiens phase and never reached the gregarious one. The absence of this last phase is discussed in the light of heterogeneous densities observed in the successive generations.     

Molecular phylogeny of ciliates: What does it tell us about the evolution of the cytoskeleton and of developmental strategies?

An rRNA phylogeny of 22 species of ciliates belonging to seven of Small and Lynn's eight classes has been obtained by distance and parsimony methods. It displays good congruence with classical systematics at low taxonomic levels and several major surprises at higher levels: (1) The species analyzed group into five major branches, four of which emerge almost simultaneously: hypotrichs, oligohymenophorans, lito-stomes, and nassophoreans corresponding to four of Small and Lynn's classes. The simultaneous emergence of these groups contradicts the long accepted view that litostomes (a group with “simple”, symmetrical, apical oral apparatus) are “primitive,” while hypotrichs are “highly evolved.” (2) Heterotrichs group with a karyorelictid, together forming the first emerging branch. While this supports the view that karyorelictids may be early-emerging ciliates, it completely explodes the traditional “spirotrichs” taxon, which united heterotrichs and hypotrichs. Instead, this reinforces the concept of Postciliodesmatophora and suggests that asymmetric oral apparatuses (i.e., with distinct paroral and adoral ciliatures) may be primitive in ciliates. The global topology of the tree therefore does not fit with the classical views of ciliate evolution, from “simple” oral apparatus and stomatogenesis to “complex” ones. Instead, a rather striking agreement with the strategy adopted to construct the cortical framework was disclosed. We noted that the cytoskeletal elements used to strengthen the cell surface could be subdivided into four main types: epiplasm, filaments, continuous microtu-bules, or basal body derived fibers. These four types fitted quite well with the major evolutionary lines disclosed by the molecular phylogeny. We therefore discuss unorthodox hypotheses assuming an early explosive radiation of ciliates into a small number of major lineages differing essentially in the solution adopted to subtend the cell surface and anchor the infraciliature. © 1992 Wiley-Liss, Inc.     

Studies onGesonula punctifrons Stål (Orthoptera: Acrididae: Cyrtacanthacridinae) attacking water-hyacinth in India

Résumé L'AcridienGesonula punctifrons St?l attaque la Jacinthe d'eau (Eichhornia crassipes) dans plusieurs parties de l'Inde et est adapté à un habitat aquatique ou semi-aquatique. Les œufs, pondus dans les pétioles des feuilles, éclosent en 3 à 4 semaines. Les larves se développent en 4 à 5 semaines et demi, avec 5 mues. Les adultes vivent au maximum 4 à 5 mois en s'alimentant seulement de Jacinthe d'eau. En essais de laboratoire cet Acridien se nourrit activement deCanna orientalis dont les tiges sont percées de trous pour la ponte par les femelles, mais aucun œuf n'est déposé. Quarante trois autres plantes d'intérêt économique ont été expérimentées: plusieurs d'entre elles ont été l'objet d'attaques légères à modérées. L'analyse de la littérature concernant les plantes-h?tes du genreGesonula et la distribution deG. punctifrons montrent que cette espèce s'est adaptée secondairement àE. crassipes. Bien que cet Acridien s'observe en grand nombre dans quelques régions, l'ensemble de ses dégats à la mauvaise herbe n'est pas suffisant pour assurer le contr?le de celle-ci.

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This research has been financed in part by a grant made by the United States Department of Agriculture under P. L. 480.     

A new species of the short-horned grasshopper genus Heteropternis Stål, 1873 (Orthoptera: Acrididae) from Central India

Heteropternis raipurensis n. sp. is described from Barnawapara Wildlife Sanctuary (Raipur, Chhattisgarh, India), and compared to H. respondens (Walker, 1859). An identification key to Asian species of Heteropternis is provided.     

Respiratory proteins in Sipunculus nudus — Implications for phylogeny and evolution of the hemerythrin family

Three major classes of respiratory proteins are known, hemoglobin, molluscan and arthropod hemocyanin, and hemerythrin (Hr). Similar to hemoglobin, respiratory Hr is packed into erythrocytes floating in the coelomic fluid and is only known from sipunculids, brachiopods, and priapulids. Owing to this scattered distribution, the presence of Hr is generally assumed to be the plesiomorphic condition without phylogenetic importance. By sequencing 2000 Expressed Sequence Tags (ESTs) from Sipunculus nudus, we found 75 Hr-coding ESTs assembled to 20 cDNA contigs classified as four distinct Hr isoforms: three polymeric Hrs (subunit A, A', and B) and the monomeric myo-hemerythrin (myoHr). Phylogenetic analyses revealed a clade of annelid and sipunculan monomeric Hrs, distinct from polymeric Hrs. Monomeric Hrs from annelids and sipunculids can be clustered together using Maximum Likelihood tree-building and network analyses, as well as applying Bayesian methods. Three distinct Hr clusters were found for S. nudus, suggesting a new monomeric Hr isoform.     

What is an 'elasmobranch'? The impact of palaeontology in understanding elasmobranch phylogeny and evolution

The Subclass Elasmobranchii is widely considered nowadays to be the sister group of the Subclass Holocephali, although chimaeroid fishes were originally classified as elasmobranchs along with modern sharks and rays. While this modern systematic treatment provides an accurate reflection of the phylogenetic relationships among extant taxa, the classification of many extinct non-holocephalan shark-like chondrichthyans as elasmobranchs is challenged. A revised, apomorphy-based definition of elasmobranchs is presented in which they are considered the equivalent of neoselachians, i.e. a monophyletic group of modern sharks and rays which not only excludes all stem and crown holocephalans, but also many Palaeozoic shark-like chondrichthyans and even close extinct relatives of neoselachians such as hybodonts. The fossil record of elasmobranchs (i.e. neoselachians) is reviewed, focusing not only on their earliest records but also on their subsequent distribution patterns through time. The value and limitations of the fossil record in answering questions about elasmobranch phylogeny are discussed. Extinction is seen as a major factor in shaping early elasmobranch history, especially during the Triassic. Extinctions may also have helped shape modern lamniform diversity, despite uncertainties surrounding the phylogenetic affinities of supposedly extinct clades such as cretoxyrhinids, anacoracids and odontids. Apart from these examples, and the supposed Cretaceous extinction of 'sclerorhynchids', elasmobranch evolution since the Jurassic has mostly involved increased diversification (especially during the Cretaceous). The biogeographical distribution of early elasmobranchs may be obscured by sampling bias, but the earliest records of numerous groups are located within the Tethyan realm. The break-up of Gondwana, and particularly the opening of the South Atlantic Ocean (together with the development of epicontinental seaways across Brazil and Africa during the Cretaceous), provided repeated opportunities for dispersal from both eastern (European) and western (Caribbean) Tethys into newly formed ocean basins.     

Chromosome numbers and DNA?C values in the genus Lippia (Verbenaceae)

The genus Lippia comprises herbs, shrubs, and small trees, including many species with medicinal properties. The species are distributed throughout South and Central America and Tropical Africa, but the majority of them occur in Brazil, Paraguay, and Argentina. The DNA?C value of 28 Brazilian species has been estimated by flow cytometry. Estimated DNA?C values ranged from 0.825?pg (L. corymbosa) to 2.150?pg (L.?brasiliensis). In addition, new chromosome numbers of 12 species have also been described, and meiotic cells with 12, 13, and 14 chromosome pairs were observed. A straightforward correlation between chromosome number and DNA?C value was not observed, probably due to two outlier species of Lippia that have been transferred from the genus Lantana. In general, the data confirm previous reports regarding the variation within the taxonomic sections and also suggest a new revision in section Zapania. Aspects of karyotypic evolution of the genus are also discussed.     

What,if anything,is a Tilapia?-mitochondrial ND2 phylogeny of tilapiines and the evolution of parental care systems in the African cichlid fishes

We estimated a novel phylogeny of tilapiine cichlid fish (an assemblage endemic to Africa and the Near East) within the African cichlid fishes on the basis of complete mitochondrial NADH dehydrogenase subunit 2 (ND2) gene sequences. The ND2 (1,047 bp) gene was sequenced in 39 tilapiine cichlids (38 species and 1 subspecies) and in an additional 14 nontilapiine cichlid species in order to evaluate the traditional morphologically based hypothesis of the respective monophyly of the tilapiine and haplochromine cichlid fish assemblages. The analyses included many additional cichlid lineages, not only the so-called tilapiines, but also lineages from Lake Tanganyika, east Africa, the Neotropics and an out-group from Madagascar with a wide range of parental care and mating systems. Our results suggest, in contrast to the historical morphology-based hypotheses from Regan (1920, 1922 ), Trewavas (1983), and Stiassny (1991), that the tilapiines do not form a monophyletic group because there is strong evidence that the genus Tilapia is not monophyletic but divided into at least five distinct groups. In contrast to this finding, an allozyme analysis of Pouyaud and Agnèse (1995), largely based on the same samples as used here, found a clustering of the Tilapia species into only two groups. This discrepancy is likely caused by the difference in resolution power of the two marker systems used. Our data suggest that only type species Tilapia sparrmanii Smith (1840) should retain the genus name TILAPIA: One particular group of tilapiines (composed of genera Sarotherodon, Oreochromis, Iranocichla, and Tristramella) is more closely related to an evolutionarily highly successful lineage, the haplochromine cichlids that compose the adaptive radiations of cichlid species flocks of east Africa. It appears that the highly adaptable biology of tilapiines is the ancestral state for all African cichlids and that the more stenotypic lifestyle of the haplochromine cichlids is derived from this condition. We reconstructed the evolution of the highly variable parental care systems on the basis of the most inclusive composite phylogeny to date of the African, Neotropical, and Madagascan cichlids with special emphasis on a group of tilapiines comprising the substrate-spawning genus Tilapia, and the mouthbrooding genera Sarotherodon and OREOCHROMIS: We demonstrate several independent origins of derived mouthbrooding behaviors in the family Cichlidae.     

Linking the molecular evolution of avian beta (β) keratins to the evolution of feathers

Feathers of today's birds are constructed of beta (β)-keratins, structural proteins of the epidermis that are found solely in reptiles and birds. Discoveries of "feathered dinosaurs" continue to stimulate interest in the evolutionary origin of feathers, but few studies have attempted to link the molecular evolution of their major structural proteins (β-keratins) to the appearance of feathers in the fossil record. Using molecular dating methods, we show that before the appearance of Anchiornis (～155 Million years ago (Ma)) the basal β-keratins of birds began diverging from their archosaurian ancestor ～216?Ma. However, the subfamily of feather β-keratins, as found in living birds, did not begin diverging until ～143?Ma. Thus, the pennaceous feathers on Anchiornis, while being constructed of avian β-keratins, most likely did not contain the feather β-keratins found in the feathers of modern birds. Our results demonstrate that the evolutionary origin of feathers does not coincide with the molecular evolution of the feather β-keratins found in modern birds. More likely, during the Late Jurassic, the epidermal structures that appeared on organisms in the lineage leading to birds, including early forms of feathers, were constructed of avian β-keratins other than those found in the feathers of modern birds. Recent biophysical studies of the β-keratins in feathers support the view that the appearance of the subfamily of feather β-keratins altered the biophysical nature of the feather establishing its role in powered flight.     

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.