Search results for "arthropod"
showing 10 items of 308 documents
Phylogeny of Hyadinini (Diptera: Ephydridae) with an Emphasis on Structures of the Proboscis
2014
Abstract. The shape of adult mouthparts (proboscis) of all genera of Hyadinini (Diptera: Ephydridae) is provided, including variability of cibarium, lacinia and the number of pseudotracheae. Its usage in phylogenetic construction is documented. All ten genera are diagnosed, including the genus Lytogaster, which is formally restored from synonymy with Hyadina. The ventral receptacle of four genera (Garifuna, Parahyadina, Parydroptera and Pelinoides) and the male terminalia of Parahyadina are presented for the first time. Monophyly of the tribe is discussed and the relationships among genera of Hyadinini are proposed. Ten Hyadinini genera are grouped into four lineages 1) Pelina group with Pe…
Description of Dryocosmus destefanii new species (Hymenoptera: Cynipidae: Cynipini) from Quercus suber L. in Italy
2018
A new species, Dryocosmus destefanii Cerasa & Melika n. sp. associated with a Cerris section oak, Quercus suber L., is described from Italy. Description, diagnosis, host associations and biology for the new species and an illustrated identification key to the Western Palaearctic Dryocosmus species are given. The description is supported by morphological and molecular data.
A taxonomic revision of the Palaearctic genus Roeseliana (Orthoptera: Tettigoniidae: Tettigoniinae: Platycleidini): a case of ongoing Mediterranean s…
2023
The genus Roeseliana presently includes 10 specific or subspecific taxa, but following different authors some of them are considered synonyms. However, the authors who have treated these taxa often did not agree with the synonymies, in particular, concerning some taxa, such as R. fedtschenkoi (Saussure, 1874) and R. roeselii (Hagenbach, 1822). The present authors examined hundreds of specimens of different taxa, for the first time were able to obtain the translation from the Russian of the description of R. fedtschenkoi, compared the main morphological characters used to discriminate different taxa, biometrics, bioacoustics and genetics of some taxa. This allowed them to conclude that it is…
Six3 demarcates the anterior-most developing brain region in bilaterian animals
2010
Abstract Background The heads of annelids (earthworms, polychaetes, and others) and arthropods (insects, myriapods, spiders, and others) and the arthropod-related onychophorans (velvet worms) show similar brain architecture and for this reason have long been considered homologous. However, this view is challenged by the 'new phylogeny' placing arthropods and annelids into distinct superphyla, Ecdysozoa and Lophotrochozoa, together with many other phyla lacking elaborate heads or brains. To compare the organisation of annelid and arthropod heads and brains at the molecular level, we investigated head regionalisation genes in various groups. Regionalisation genes subdivide developing animals …
Fine Determination of the Molt Cycle Stages in Orchestia cavimana Heller (Crustacea: Amphipoda)
1986
ABSTRACT The successive stages of the molt cycle of the terrestrial crustacean amphipod Orchestia cavimana are finely described and illustrated in order to give precise reference marks for experimental, physiological, and biochemical studies. The method of determination, very rapid and easy, is based upon the observation of the morphogenesis of the dactylopodite and the propodite from the third pereiopod. The events of the early morphogenesis of the claw from the dactylopodite divide the intermolt period C into four stages. The formation of spines and the secretion of the epicuticle and then the procuticle at the level of the propodite divide the premolt period into seven stages. The entire…
Weather impacts on interactions between nesting birds, nest-dwelling ectoparasites and ants.
2022
AbstractWeather has a dominant impact on organisms, including their life histories and interspecific interactions. Yet, for nesting birds, and the arthropods inhabiting bird nests, the direct and cascading effects of weather are poorly known. We explored the influence of ambient temperatures and rainfall on the cohabitation of dome-shaped bird nests by Wood Warblers Phylloscopus sibilatrix, their blowfly Protocalliphora azurea ectoparasites, and predatory Myrmica and Lasius ants that may provide nest sanitation. We sampled blowflies and ants in 129 nests, and measured warbler nestlings during 2018–2020 in the primeval Białowieża Forest, eastern Poland. The probability of ectoparasites occur…
Two new species of the genus emNemaspela/em Šilhavý from caves in Georgia (Opiliones: Nemastomatidae).
2021
Two highly specialized endemic troglobiotic harvestman species of the genus Nemaspela Šilhavý, 1966 are described. N. melouri sp. nov. from Melouri Cave and N. prometheus sp. nov. from Prometheus Cave (Sataplia-Tskaltubo karst massif, Imereti region, western Georgia), respectively. Despite the fact that the entrances of the caves are positioned only 2.5 km apart, the new taxa differ from each other distinctly by presence vs. absence of male cheliceral apophysis, which is lacking in the second species. A key to the Caucasian species of the genus is provided. Relationships of Nemaspela species within the genus and with hypothetical epigean ancestors are discussed.
The Centetostoma scabriculum complex—a group of three cryptic species (Arachnida: Opiliones: Nemastomatidae)
2011
Nemastoma scabriculum Simon, 1879 turned out to be a group of three closely related species of the Pyrenees in SW Europe (France and Spain). Though the species are similar in general habit they can easily be recognized by external morphology (structure of the apophysis of male chelicerae) and male genital morphology (penial structure). For Nemastoma scabriculum Simon, 1879 sensu stricto a lectotype is designated. The synonymous Nemastoma ventalloi Mello-Leitao, 1936 is considered to be a distinct species and is re-described. The third species of the group is described as new, Centetostoma juberthiei sp. n. Though partly sympatric in their restricted Pyrenean area, the individual species are…
Gluing the ‘unwettable’: soil-dwelling harvestmen use viscoelastic fluids for capturing springtails
2014
Gluing can be a highly efficient mechanism of prey capture, as it should require less complex sensory–muscular feedback. Whereas it is well known in insects, this mechanism is much less studied in arachnids, except spiders. Soil-dwelling harvestmen (Opiliones, Nemastomatidae) bear drumstick-like glandular hairs (clavate setae) at their pedipalps, which were previously hypothesized to be sticky and used in prey capture. However, clear evidence for this was lacking to date. Using high-speed videography, we found that the harvestman Mitostoma chrysomelas was able to capture fast-moving springtails (Collembola) just by a slight touch of the pedipalp. Adhesion of single clavate setae increased p…
What Could Be a Primary Cause of Multiple Sclerosis: Is It an Autoimmunity Triggered by Chronic Protozoan Infection?
2013
The generally accepted paradigm of multiple sclerosis is the autoimmune one; still, a body of evidence suggests that this disease may actually be triggered by an infectious factor. In this paper, it is hypothesized that multiple sclerosis may actually be a rare complication of a protozoan infection, which is usually asymptomatic but in some susceptible individuals is accompanied by autoimmune attack against the nervous tissue. If multiple sclerosis were actually caused by such an infection, then a microorganism responsible should exhibit several properties: it (i) is transmitted by an arthropod vector; (ii) is characterized by specific metabolism of the lipids; (iii) should be dependent on …