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Martin Zimmer - One of the best experts on this subject based on the ideXlab platform.
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balancing nutritional requirements for copper in the common Woodlouse porcellio scaber isopoda oniscidea
Applied Soil Ecology, 2003Co-Authors: Melanie Weisenburg, Martin ZimmerAbstract:We studied the copper budget, feeding preferences and digestive processes in the common Woodlouse, Porcellio scaber, feeding on experimentally copper-contaminated leaf litter. Isopods lost copper from their body storage when feeding on a copper-free artificial diet for 4 weeks. The copper balance in subsequent feeding experiments depended on both the pre-experimental copper treatment and the copper content of leaf litter that has been experimentally increased to mimic a food source from a copper-contaminated area. Although the overall copper uptake did not depend on microbial activity, the copper content of isopod feces from feeding experiments provided evidence for increased copper absorption through leaf litter-colonizing microbiota. Consumption of leaf litter was influenced by the pre-experimental copper treatment of isopods and the copper content of the leaf litter. Food assimilation was affected by microbial leaf litter activity and both pre-experimental copper treatment of isopods and copper content of the leaf litter. Growth rates differed between food sources, but no effect of copper or microbial activity was evident. The duration of molt cycles was prolonged when feeding on copper-contaminated leaf litter, indicating long-term sub-lethal toxic effects of copper contamination, but both microbial activity of experimental leaf litter and pre-experimental acclimatization of isopods to moderate copper contamination reduced this effect. In feeding preference tests, both copper-fed and copper-deficient woodlice preferred copper-poor leaf litter over experimentally contaminated leaf litter with high copper content. The preference for copper-poor leaf litter was neither affected by the litter type nor by the activity of litter-colonizing microbiota, but appears to indicate the avoidance of copper-contaminated litter. Sensory preference tests provided evidence for direct detection of copper in leaf litter extracts through contact-chemoreception. Isopods turned significantly more often towards aqueous extracts of copper-poor leaf litter than of copper-contaminated leaf litter. Our data show that even copper-deficient isopods avoid excessive consumption of highly copper-contaminated leaf litter although copper increases its digestibility. Copper absorption is independent of the body copper content but is facilitated by leaf litter-colonizing microbiota. Further, microbiota as well as previous exposure to copper reduce the toxic effects of copper.
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Microorganisms and Cellulose Digestion in the Gut of the Woodlouse Porcellio scaber
Journal of Chemical Ecology, 1998Co-Authors: Martin Zimmer, Werner ToppAbstract:In the common Woodlouse Porcellio scaber different parts of the gut were observed with respect to microbial counts, cellulose activity, and degradation of cellulose. Cellulose is mainly digested in the anterior part of the hindgut, as was indicated by the distribution of cellulolytic activity and the decrease of cellulose content inside the gut. The cellulases woodlice utilize for the degradation of litter are mainly produced by endosymbiotic bacteria in the hepatopancreas rather than by microorganisms ingested with the food. Microorganisms ingested with the litter are digested in the anterior part of the hindgut and may provide an important food source. In the posterior hindgut, bacterial proliferation ensures microbial colonization of feces.
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does leaf litter quality influence population parameters of the common Woodlouse porcellio scaber crustacea isopoda
Biology and Fertility of Soils, 1997Co-Authors: Martin Zimmer, Werner ToppAbstract:Population parameters (mortality of females, reproductive success, longevity of juveniles) of the common Woodlouse, Porcellio scaber (Isopoda, Oniscidea), were examined with respect to the influence of varying leaf litter attributes: pH level, microbial cellulase activity, microbial dehydrogenase activity, protein content, nitrogen content, water content, tannin content, total phenol content and toughness of the leaves. These attributes were combined by using Principal Component Analysis. We obtained three Principal Components (PC) that were defined as “acidification,”“microorganisms” and “tree species.” The PCs explained 85% of the variance of leaf litter attributes. The PC “acidification” mainly influenced the mortality of females (P<0.001), while the longevity of juveniles showed significant correlation to the PC “microorganisms” (P<0.05). The PC “tree species” showed no influence on the observed population parameters, indicating that the leaf litter species itself had no direct influence on the population parameters of P. scaber. The reproductive success of females could not be explained by either of the PCs, but was influenced by cellulolytically active microorganisms (P<0.01). From these results, we conclude that acidification and reduced microbial activity in the field will cause a decrease in population density of P. scaber.
J.p. Odendaal - One of the best experts on this subject based on the ideXlab platform.
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Effect of Cadmium on Haemocyte Viability of the Woodlouse Porcellio laevis (Isopoda, Crustacea)
Bulletin of Environmental Contamination and Toxicology, 2009Co-Authors: R. G. Snyman, J.p. OdendaalAbstract:This study investigated the effects of cadmium on haemocyte viability of the Woodlouse Porcellio laevis , using the trypan blue exclusion assay. The ultimate aim is to determine the usefulness of this cellular response as biomarker of cadmium exposure. Results showed that exposure to sublethal concentrations of cadmium, with concomitant cadmium accumulation in the body, significantly lowered the percentages of viable haemocytes in P. laevis . This response was already observed after the first week of exposure and could therefore possibly serve as an early warning of cadmium exposure. A field study is needed to validate these findings.
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the toxicity of sublethal lead concentrations for the Woodlouse porcellio laevis crustacea isopoda
Biology and Fertility of Soils, 1999Co-Authors: J.p. Odendaal, A J ReineckeAbstract:The effects of sublethal concentrations of lead nitrate on the terrestrial isopod Porcellio laevis were studied experimentally under controlled conditions over a period of 8 weeks. Changes in body mass were recorded. Avoidance-behaviour studies were undertaken to determine whether P. laevis can detect and possibly avoid lead in the environment. P. laevis was affected negatively by the presence of lead nitrate and showed a loss in body mass. More than 86% of the total body burden of lead was compartmentalized in the hepatopancreas. The isopods were capable of avoiding leaves contaminated with 200 mg kg–1 lead nitrate in behavioural tests but did not avoid leaves contaminated with a higher concentration.
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Short-term toxicological effects of cadmium on the Woodlouse, Porcellio laevis (Crustacea, Isopoda).
Ecotoxicology and Environmental Safety, 1999Co-Authors: J.p. Odendaal, Adriaan J. ReineckeAbstract:Abstract Terrestrial isopods have been used in a number of studies as test organisms concerning the effects of chemicals in a (eco-)toxicological context. They are saprophages, which are in direct contact with polluted plant material. Cadmium is a metal with no known biological function and is toxic to life. There are a variety of anthropogenic sources of cadmium in the environment. The aims of this study were to determine the LC50for cadmium sulfate forPorcellio laevisand the acute effect of this metal salt on the mass of this species and also to determine ifP. laeviscould distinguish and avoid cadmium sulfate-contaminated leaves. Acute toxicity tests and behavioral tests were conducted using concentrations ranging from 10,000 to 40,000mg/kg cadmium sulfate. The LC50obtained of 26,700 mg/kg cadmium sulfate is an indication ofP. laevis' tolerance to cadmium contamination.P. laevisalso exhibited the ability to distinguish and avoid leaves contaminated with high cadmium sulfate levels.
Werner Topp - One of the best experts on this subject based on the ideXlab platform.
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Microorganisms and Cellulose Digestion in the Gut of the Woodlouse Porcellio scaber
Journal of Chemical Ecology, 1998Co-Authors: Martin Zimmer, Werner ToppAbstract:In the common Woodlouse Porcellio scaber different parts of the gut were observed with respect to microbial counts, cellulose activity, and degradation of cellulose. Cellulose is mainly digested in the anterior part of the hindgut, as was indicated by the distribution of cellulolytic activity and the decrease of cellulose content inside the gut. The cellulases woodlice utilize for the degradation of litter are mainly produced by endosymbiotic bacteria in the hepatopancreas rather than by microorganisms ingested with the food. Microorganisms ingested with the litter are digested in the anterior part of the hindgut and may provide an important food source. In the posterior hindgut, bacterial proliferation ensures microbial colonization of feces.
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does leaf litter quality influence population parameters of the common Woodlouse porcellio scaber crustacea isopoda
Biology and Fertility of Soils, 1997Co-Authors: Martin Zimmer, Werner ToppAbstract:Population parameters (mortality of females, reproductive success, longevity of juveniles) of the common Woodlouse, Porcellio scaber (Isopoda, Oniscidea), were examined with respect to the influence of varying leaf litter attributes: pH level, microbial cellulase activity, microbial dehydrogenase activity, protein content, nitrogen content, water content, tannin content, total phenol content and toughness of the leaves. These attributes were combined by using Principal Component Analysis. We obtained three Principal Components (PC) that were defined as “acidification,”“microorganisms” and “tree species.” The PCs explained 85% of the variance of leaf litter attributes. The PC “acidification” mainly influenced the mortality of females (P<0.001), while the longevity of juveniles showed significant correlation to the PC “microorganisms” (P<0.05). The PC “tree species” showed no influence on the observed population parameters, indicating that the leaf litter species itself had no direct influence on the population parameters of P. scaber. The reproductive success of females could not be explained by either of the PCs, but was influenced by cellulolytically active microorganisms (P<0.01). From these results, we conclude that acidification and reduced microbial activity in the field will cause a decrease in population density of P. scaber.
Mark Bayley - One of the best experts on this subject based on the ideXlab platform.
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Woodlouse locomotor behavior in the assessment of clean and contaminated field sites
Environmental Toxicology and Chemistry, 1997Co-Authors: Mark Bayley, Erik Baatrup, Poul BjerregaardAbstract:Specimens of the Woodlouse Oniscus asellus were collected at four clean field sites and from a recently closed iron foundry heavily contaminated with zinc, lead, chromium, and nickel. Each of the 30 woodlice per group was housed individually and acclimatized to laboratory conditions for 2 d on a humid plaster of paris substrate. Thereafter, the locomotor behavior of each animal was measured for 4 h employing automated computer-aided video tracking. Linear discriminant analysis of five locomotor parameters revealed average velocity and path length as the principle components separating the polluted site and control animals. Post hoc analysis of the discriminant variable for animals from all five sites showed that the animals from the polluted site where significantly hyperactive when compared to all controls. Further, control animals collected from sites separated by several hundred kilometers were remarkably similar in their locomotor behavior. This preliminary study highlights the potential utility of quantitative analysis of animal locomotor behavior in environmental monitoring.
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Prolonged effects of the insecticide dimethoate on locomotor behaviour in the Woodlouse, Porcellio scaber Latr. (isopoda)
Ecotoxicology, 1995Co-Authors: Mark BayleyAbstract:Beneficial invertebrates living in hedgerows and woodland adjacent to arable land, are almost inevitably exposed to small doses of pesticides. This can present a threat to these invertebrates even at sublethal levels. Locomotor behaviour is intrinsic to many more complex behavioural responses such as predator avoidance, migration, mate seeking, etc., but is also closely related to the physiological status of the animal. Further, locomotor activity is quantifiable with the aid of modern video and computer technology. In the present study, the effect of a 48 h exposure of the Woodlouse Porcellio scaber to soil contaminated with one-tenth of the LD_20 (96 h) dimethoate dose was quantified using computer-automated video tracking. Dimethoate-exposed woodlice were recorded for one night prior to dimethoate exposure and for two nights on contaminated soil. After a recovery period of 21 days, the woodlice were recorded for a further night. Control animals were recorded in parallel on soil treated with water. Over the 48 h of exposure, dimethoate induced a gradually increasing hyperactivity in terms of time spent in activity, mean velocity and path length and a suppression of turning rate when compared with controls. No recovery was seen after the 21 days on uncontaminated soil. These effects were statistically significant only in male woodlice.
Francisco Bozinovic - One of the best experts on this subject based on the ideXlab platform.
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maternal effects maternal body size and offspring energetics a study in the common Woodlouse porcellio laevis
Comparative Biochemistry and Physiology A-molecular & Integrative Physiology, 2007Co-Authors: Leonardo D Bacigalupe, Marco A Lardies, Nury M Araya, Mauricio J Carter, Tamara P Catalana, Francisco BozinovicAbstract:What are the consequences of the natural variation in maternal body mass on offspring energetic performance? How are performance traits related to thermal physiology and energetics phenotypically integrated on offspring? To answer these questions, fifty breeding pairs of the common terrestrial isopod Porcellio laevis were set up in the lab. Physiological performance, thermal tolerance and thermal sensitivity were measured in F1 adults. Maternal effects were estimated as: the direct influence of maternal body mass and the variation associated with mothers. Phenotypic integration was evaluated using path analysis. Our results show that: (1) maternal body size affects positively offspring long-term metabolism, (2) maternal variation was significant in many of the physiological traits and (3) there is an intricate set of relationships among traits and importantly, that offspring exhibited compensational strategies among metabolism, thermal sensitivity and thermal tolerance traits. Even if we cannot clearly state whether these maternal influences were because of the genes or the environment that mothers provided and thus no predictions can be done regarding their evolutionary consequences, it seems clear that the role of maternal effects on physiology can no longer be ignored. In this sense, there's a lot to be gained by incorporating explicit experimental protocols to test for maternal effects.
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interpopulational variation in recovery time from chill coma along a geographic gradient a study in the common Woodlouse porcellio laevis
Journal of Insect Physiology, 2005Co-Authors: Luis E Castaneda, Marco A Lardies, Francisco BozinovicAbstract:Extreme temperatures restrict the performance of terrestrial arthropods and variations in low temperatures on a latitudinal scale influence physiological variables. Recovery time from chill coma is a measure of cold tolerance and it is a good index of climatic adaptation. We tested differences in recovery time of the common Woodlouse (Porcellio laevis) exposed to different thermal conditions. Individuals were sampled from four different populations in Chile, spanning a latitudinal range of ∼10°. Significant differences were found in recovery time among experimental temperatures and among populations, but no interaction between these factors. The results of recovery time in P. laevis showed a positive increment with annual mean minimum temperature, indicating that there is geographical variation in recovery time. While body mass presented interpopulational variation, this variation was not associated with thermal variables or latitude. Overall, our results agree with previous studies in the sense that recovery time from chill coma decreases towards high latitudes, and it is independent of taxa, continent and hemisphere.
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testing the metabolic cold adaptation hypothesis an intraspecific latitudinal comparison in the common Woodlouse
2004Co-Authors: Marco A Lardies, Leonardo D Bacigalupe, Francisco BozinovicAbstract:The metabolic cold adaptation (MCA) hypothesis predicts an increase in the metabolic rate of ectotherms from cold environments compared with their more temperate counterparts. This adaptive hypothesis is one of the most controversial in physiological ecology, for which the evidence comes principally from the meta-analysis of data sets of arthropods. Important for the study of metabolic cold adaptation are comparisons at a geographic level, especially on a latitudinal scale, because mean annual temperature decreases towards high latitudes. Furthermore, few studies have conducted intraspecific comparisons of metabolic rates along a latitudinal gradient. We tested the MCA hypothesis in the common Woodlouse, Porcellio laevis, using different populations along a distributional range with a wide range of mean ambient temperatures (5, 12, 18 and 25C) in Chile. Our results demonstrated that metabolic rate increased towards low latitudes – that is, woodlice from the warmer (i.e. northern) part of the distribution range had markedly higher metabolic rates than those from the cooler (i.e. southern) region, for almost all experimental temperatures. Thus, our results provide direct evidence of intraspecific latitudinal differences in metabolism, rejecting the MCA hypothesis, which is more difficult to resolve with interspecific level comparisons.
