| comparative anatomy of serotonin-like immunoreactive neurons in isopods: putative homologues in several species. | it is now commonly accepted that the arthropod nervous system has evolved only once, and so homologies between crustacean and insect nervous systems can be meaningfully sought. to do this, we have examined the distribution of serotonin (5-hydroxytryptamine)-like immunoreactive neurons in the central nervous system (cns) of four common british isopods. two species of terrestrial woodlouse, oniscus asellus and armadillidium vulgare, the littoral sea slater, ligia oceanica, and the aquatic water ho ... | 1994 | 7814675 |
| wolbachia infection in the terrestrial isopod oniscus asellus: sex ratio distortion and effect on fecundity | maternally inherited wolbachia bacteria are widespread in arthropods where they are responsible for various reproductive alterations. in terrestrial isopods (woodlice), wolbachia may induce feminization or cytoplasmic incompatibility (ci), but their effect remains unknown in most host species. to increase our understanding of host/symbiont interactions in terrestrial isopods, the effect of wolbachia was investigated in the oniscidean oniscus asellus, mainly to discriminate between feminization a ... | 1999 | 10583549 |
| environmental effects of radionuclides--observations on natural ecosystems. | to better quantify risk to non-human species from exposure to environmental radioactivity, understanding of the behaviour of radionuclides in the biosphere needs to be increased. this study outlines current thinking on ecological risk assessment (era) methodology and applies the indicator species or critical groups approach to biota inhabiting a semi-natural coniferous woodland contaminated with the radionuclides 137cs, 238pu, 239+240pu and 241am. the majority of these radionuclides originate fr ... | 2000 | 10750953 |
| an experimental infection model for tetrameres americana (cram 1927). | an experimental infection model for the heteroecious spiruid nematode tetrameres americana (cram 1927) was developed. the cockroach blattella germanica (l.) and the locust locusta migratoria (l.) were found to serve as intermediate hosts for the parasite. t. americana larvae developed to full maturity in these intermediate hosts and were infective to young lohman brown chickens after 32 days in the cockroach and 28 days in the locust. the maximum length of the larvae was reached in the insects a ... | 2004 | 15616857 |
| energy reserves and metal-storage granules in the hepatopancreas of oniscus asellus and porcellio scaber (isopoda) from a metal gradient at avonmouth, uk. | isopods taken from populations of onsicus asellus and porcellio scaber from long-term polluted sites in the vicinity of metal smelting works at avonmouth, south west england, and from a control site near tübingen, south germany, were examined for the frequency and size of metal-containing granules (spherites), lipid droplets and glycogen in their hepatopancreas. the number and size of spherites in the hepatopancreas of o. asellus increased with decreasing distance to the smelter, but such a tren ... | 2004 | 15736849 |
| bacterial symbionts in the hepatopancreas of isopods: diversity and environmental transmission. | the midgut glands (hepatopancreas) of terrestrial isopods contain bacterial symbionts. we analysed the phylogenetic diversity of hepatopancreatic bacteria in isopod species from various suborders colonizing marine, semiterrestrial, terrestrial and freshwater habitats. hepatopancreatic bacteria were absent in the marine isopod idotea balthica (valvifera). the symbiotic bacteria present in the midgut glands of the freshwater isopod asellus aquaticus (asellota) were closely related to members of th ... | 2007 | 17506824 |
| potential macro-detritivore range expansion into the subarctic stimulates litter decomposition: a new positive feedback mechanism to climate change? | as a result of low decomposition rates, high-latitude ecosystems store large amounts of carbon. litter decomposition in these ecosystems is constrained by harsh abiotic conditions, but also by the absence of macro-detritivores. we have studied the potential effects of their climate change-driven northward range expansion on the decomposition of two contrasting subarctic litter types. litter of alnus incana and betula pubescens was incubated in microcosms together with monocultures and all possib ... | 2011 | 21735203 |
| extracellular application of cobalt: a fast and simple method for delineating invertebrate neurosecretory pathways. | the extracellular cobalt backfilling technique was shown to be an excellent method to obtain cobalt backfills of invertebrate neurosecretory cells (nscs). aqueous cobalt was placed in an extracellular suction electrode into which a portion of a neurohaemal (nh) region containing the axons and/or terminals of nscs was drawn. spontaneously discharging extracellular action potentials were recorded as the cobalt was applied to the nh region, and the greater the electrical activity, the more extensiv ... | 2012 | 3347089 |
| ultrastructure and distribution of identified neurosecretory terminals in the sinus gland of the terrestrial isopod oniscus asellus. | an ultrastructural study of the sinus gland of the terrestrial isopod, oniscus asellus, reveals that this structure consists of two regions: the bulb, which is attached by a narrow stalk to the optic lobe, and the lateral extension, which extends from the bulb along the optic tract to the compound eye. the bulb has a distal region containing only neurosecretory terminals, and a proximal region containing terminals, glial cells, and axons that give rise to the distally located terminals. in total ... | 2013 | 4012770 |
| the toxicity of zinc to terrestrial isopods in a "standard" laboratory test. | a method is described for assessing the effects of metals on the food consumption rate of isopods from measurements of fecal production. the effects of zinc in the diets of two isopod species, porcellio scaber and oniscus asellus, were tested. the metal was fed to the isopods on leaves of field maple (acer campestre) contaminated with concentrations ranging between 1000 and 10,000 micrograms zn g-1 leaf dry wt. significant reductions in feeding rates were observed of the highest concentrations o ... | 1995 | 7544260 |
| effects of elevated co2 on litter chemistry and subsequent invertebrate detritivore feeding responses. | elevated atmospheric co2 can change foliar tissue chemistry. this alters leaf litter palatability to macroinvertebrate detritivores with consequences for decomposition, nutrient turnover, and food-web structure. currently there is no consensus on the link between co2 enrichment, litter chemistry, and macroinvertebrate-mediated leaf decomposition. to identify any unifying mechanisms, we presented eight invertebrate species from aquatic and terrestrial ecosystems with litter from alnus glutinosa ( ... | 2014 | 24465985 |
| the 70 kd heat shock protein (hsp 70) in soil invertebrates: a possible tool for monitoring environmental toxicants. | the expression of hsp 70 after heat shock or exposure to heavy metals/molluscicides was investigated by fluorography or immunoblot in three diplopods (glomeris marginata, cylindroiulus punctatus, tachypodoiulus niger), two slugs (deroceras reticulatum, arion ater), and one isopod (oniscus asellus). in o. asellus, hsp 70 expression occurred after heat shock and also after lead treatment, whereby a solution of 100 mg/kg pb2+ was sufficient. animals of the same species taken from a heavy metal poll ... | 1992 | 1616318 |
| body shape in terrestrial isopods: a morphological mechanism to resist desiccation? | woodlice are fully terrestrial crustaceans and are known to be sensitive to water loss. their half-ellipsoidal shapes represent simple models in which to investigate theoretical assumptions about organism morphology and rates of exchange with the environment. we examine the influence of surface area and mass on the desiccation rates in three eco-morphologically different species of woodlice: oniscus asellus, porcellio scaber, and armadillidium vulgare. our analysis indicates that the rate of wat ... | 2015 | 26289755 |
| function-related structural characters and their modifications in the hindgut epithelium of two terrestrial isopods, armadillidium vulgare and oniscus asellus. | intercellular junctions of the hindgut epithelial cells of two terrestrial isopods, armadillidium vulgare and oniscus asellus, are described. long septate desmosomes occupy the subluminal region while gap junctions, zonulae adherens and intercellular spaces characterize the remainder of the convoluted lateral cell borders. the specialized junctional complexes and the ultrastructural morphology of the cells indicate that the terrestrial isopod hindgut epithelium functions in transport. using mito ... | 1982 | 7117666 |
| a comparative study on the fine structure of developing spermatozoa in the isopod, oniscus asellus, and the amphipod, orchestoidea sp. | | 1966 | 6011652 |