Porcellio Laevis Research Articles

Effects of Pirimiphos-Methyl on Non-Target Invertebrates.

The effects of pirimiphos-methyl have previously been assessed on blood-sucking insect species, pollinating insects, and target crop pest species. The sensitivity of non-target zoophagous and saprophage species to this insecticide remains largely unstudied. In laboratory conditions, we assessed the susceptibility of 43 species of invertebrates to pirimiphos-methyl. The most tolerant species to this insecticide were Pyrrhocoris apterus (LC50 measured over 60 mg/m2), Cylindroiulus truncorum, Pterostichus niger, Harpalus rufipes, Lithobius forficatus, and Carabus hortensis (LC50 ranged from 25 to 50 mg/m2). Average tolerance to pirimiphos-methyl was displayed by Ophonus rufibarbis, Teuchestes fossor, Silpha carinata, Badister sodalis, Rugilus rufipes, Phosphuga atrata, Porcellio laevis, Pterostichus oblongopunctatus, Aphodius foetens, Lasius fuliginosus, Oxypselaphus obscurus, Platydracus fulvipes, Myrmica ruginodis, Xantholinus tricolor, and Megaphyllum sp. (LC50 for those species ranged from 12 to 24 mg/m2). Higher sensitivity to this insecticide was seen for Amara nitida, Leistus ferrugineus, Harpalus xanthopus winkleri, Philonthus nitidus, Pterostichus melanarius, Harpalus latus, Limodromus assimilis, Philonthus decorus, Tachinus signatus, Ponera coarctata, Carabus convexus, Philonthus coprophilus, Philonthus laevicollis, Platydracus latebricola, Labia minor, and Carabus granulatus (LC50 for those species ranged from 6 to 12 mg/m2). The greatest sensitivity to pirimiphos-methyl was observed in Hister fenestus, Drusilla canaliculata, Bisnius fimetarius, Oxytelus sculptus, Lasius niger, and Lasius flavus (LC50 ranged from 0.4 to 6 mg/m2). We found a relationship between the parameters of bodies of invertebrates (the average body length and dry body mass) and sensitivity to pirimiphos-methyl. With an increase in body sizes of invertebrates, the tolerance to the insecticide increased (per each mm of body length, LC50 increased by 0.82 mg/m2 on average). We identified no relationship between the trophic specialization and sensitivity to the insecticide.

Redescription of Terrestrial Isopod Porcellio laevis Collected From Sohag Governorate, Egypt with an Overview of Epicuticular Structures Using Scanning Electron Microscopy

Redescription of Terrestrial Isopod Porcellio laevis Collected From Sohag Governorate, Egypt with an Overview of Epicuticular Structures Using Scanning Electron Microscopy

Morphological, Molecular Identification and Genetic Diversity Assessment of Three Terrestrial Isopods from the High-Altitude Region

Terrestrial specimens were collected from Ashshafa, a south-western highland area in Saudi Arabia. Three species, i.e., Porcellio laevis, Porcellionides pruinosus (Porcellionidae), and Armadillidium vulgare (Armadillidiidae), were identified in this study based on their morphological characteristics. Partial mitochondrial cytochrome C oxidase subunit I (COI) gene sequences were used for DNA barcoding and biodiversity assessments. A phylogenetic tree of 22 haplotypes from 35 specimens of the three isopod species was drawn from the most similar sequences obtained from BLAST with the associated accession numbers. The tree included two clades. The first clade included samples of P. laevis and P. pruinosus, whereas the second clade included samples of A. vulgare. Each identified species formed a distinct subclade within the main clade, along with similar sequences obtained from the NCBI database. The heat map of genetic distance among haplotypes shows the haplotype diversity (Hd) ranged from 0.590 to 0.933 (mean = 0.767) and total nucleotide diversity (πT) ranged from 0.001 to 0.089 (mean=0.049), with a similar trend observed for nucleotide diversity per site (θw) ranged from 0.001 to 0.80 (mean = 0.049). In contrast, synonymous nucleotide diversity (πs), mean=0.009, was low compared to nonsynonymous nucleotide diversity (πs), mean=0.060, across all species. In conclusion, the morphological identification of terrestrial isopods was confirmed using COI gene sequencing of mitochondrial DNA. These results will be helpful in developing a deeper isopod identification method.

Terrestrial Isopods Generate Microplastics from Low-Density Polyethylene Without Effects on Survival.

With concern growing regarding the impact of microplastics (MPs) on terrestrial ecosystems, it is important to assess the role invertebrates may play in the fate of MPs within these ecosystems. Commonly, MPs enter these environments through improperly discarded waste or the application of treated biosolids and/or wastewater on agricultural soils. The present study investigated whether three species of terrestrial isopod (Porcellio scaber, Porcellio laevis, and Porcellionides pruinosus) ingest plastic debris and generate MPs during exposures varying from 24 h to 14 days and whether this may have an adverse effect on their health. Test vessels were designed to expose isopods to plastic fragments in the form of polyethylene plastic foam. Isopods were exposed to plastic that was either (1) pristine, or (2) weathered in a soil and water solution prior to incorporation in test vessels. When exposed to weathered polyethylene, all three species generated MPs (minimum-maximum size values for all durations inclusive: P. laevis = 114-1673 µm, P. scaber = 99-1635 µm, P. pruinosus = 85-1113 µm) through the consumption of macroplastic fragments with no observed impact on their health. In the shorter-duration exposures, the number of MPs generated by the isopod species in the present study was highly variable between experimental vessels (minimum-maximum generated MPs for 14-day exposure: P. laevis = 25-420, P. scaber = 50-583, P. pruinosus = 48-311). However, as the exposure durations increased, there was a clear trend of increasing MP generation, indicating that the isopods continued to consume the plastic fragments as long as the surface was weathered. A significant difference in the size of generated MPs was observed as well, with smaller isopod species generating smaller MP fragments on average. The results of the present study confirm that certain species of isopod can contribute to the generation of MPs, which constitutes an additional pathway of MP exposure to soil ecosystems. Environ Toxicol Chem 2024;43:784-792. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Evaluating thermal niche overlap of a predator–prey system: Do spiders choose suboptimal temperatures in pursuit of prey?

AbstractEctotherm predators and their prey could potentially respond differently to habitat temperatures. Predators might select higher temperatures to increase their probability of capture while prey could select lower or higher temperatures that may enhance their escape capability. We used a combination of field and laboratory analyses to characterise the thermal niches of predator species and their potential arthropod prey. We studied a predator–prey system in northern Chile using a common desert‐dwelling spider Loxosceles laeta and three potential prey: a tenebrionid beetle Psammetichus costatus (Coleoptera), Pycnoscelus surinamensis (Blattodea) and Porcellio laevis (Isopoda). Results showed that the predator L. laeta selects warmer temperatures (Tp = 27.22 ± 4.87°C) in laboratory and lower temperatures in field conditions (Ts = 20.8 ± 1.59°C), with low temperatures in the morning and high temperatures at night. The three prey species had lower and different preferred temperatures than the predator in laboratory conditions. However, we found a high overlap in the thermal niche between the predator and their prey in field conditions, whereby the predator selected similar temperatures to its prey, one exception being P. laevis that chooses completely different habitat temperatures. This suggests that predators look for their prey in places with low temperatures that are not thermally suitable for them, whereas the prey may use this strategy of selecting low temperatures to evade potential predators.

Effects of moisture decrease on behavioural and life history traits in three species of terrestrial isopods

In the context of the predicted global warming, we investigated whether the feeding activity and the behaviour of three Oniscidean species (Porcellionides pruinosus, Porcellio laevis and Armadillidium tunisiense) would be affected by the relative humidity (RH) decrease. A decreasing gradient of relative humidity (90%, 70% and 50%) was used to study the impact of predicted climate change on the survival rate, litter consumption rate, growth efficiency, faeces production, localization and stress behaviour within woodlice. After 3 weeks of exposure, we found that all species were variously affected by the RH decrease. The species A. tunisiense showed to be the least affected by the increased dry conditions. In driest conditions, woodlice spend less time at foraging inducing a low rate of litter consumption and faeces production. Perhaps, the authors findings could contribute to changes in the decomposition process and then the soil functionality.

Geographic variation of litter chemistry and palatability in an invasive plant versus its native competitor

AbstractAimLatitudinal variation in biotic interactions is recognized as a driver underlying variation in plant invasion success and therefore an important issue in conservation biogeography. However, previous studies have mainly focused on interactions between living plants and herbivores, whereas litter traits and detritivory have been hardly studied along latitude or compared between native and invasive plants. Our aim was to compare latitudinal variation in leaf litter chemistry and palatability to detritivores between invasive and native plants, and investigate which chemical traits determine detritivory and whether they are climate‐driven.LocationChina.TaxaSpartina alterniflora, Phragmites australis, Porcellio laevis, Chiromantes dehaani.MethodsWe combined field surveys with laboratory experiments to compare latitudinal variation in litter chemistry between the widespread invasive Spartina alterniflora and its native competitor Phragmites australis across their co‐occurring range (20.9–40.7° N, ~2200 km). For both species, we examined litter palatability to two common detritivores (Porcellio laevis and Chiromantes dehaani) along the same latitude. We also analysed relationships among climate, litter traits and detritivory.ResultsIn five of nine litter traits, we found latitudinal clines, with little difference between the two plant species in how they responded across the gradient. Litter palatability decreased with increasing latitude, but was generally higher in Spartina than Phragmites. Two key litter traits (C:P ratio and flavonoid content) were significantly associated with temperature of origin and with detritivory.Main ConclusionsThere were geographic clines in litter traits and palatability, with strong links between climate, litter chemistry and detritivory, in both Spartina and Phragmites. Spartina litter, however, was more rapidly decomposed by detritivores, which could create positive feedbacks, and contributes to the successful Spartina invasion along China's coast. Future ecological restoration projects should therefore dispose Spartina plant tissue or litter off‐site, to reduce the competitiveness of Spartina and support the conservation of native Phragmites.

Identification and biodiversity patterns of Aspergillus species isolated from some soil invertebrates at high altitude using morphological characteristics and phylogenetic analyses.

The carcinogenic, mutagenic, and teratogenic chemicals such as aflatoxin are a worldwide health problem. Aspergillus spp., responsible for most cases of aflatoxin contamination, are common in the environment and spread easily to many different types of food. The objectives of this study were to conduct a survey of fungi associated with three soil invertebrates in Taif, Saudi Arabia, identify these isolates and explore mycotoxins formation. In total, 114 fungal isolates were collected from various soil invertebrates (millipedes, Armadillidium vulgare and Porcellio laevis) in Taif, Saudi Arabia, among them, 22 isolates were identified as Aspergillus spp. based on morphological and molecular characteristics followed by both Fusarium and Penicillium. The sequences of ITS 1 and ITS 4 were utilized. Using bootstrap analysis, phylogenetic tree was split into two distinct clusters. Five sub clusters were included inside the first major cluster, and their bootstrap value was 99%. While, there were two small clusters in the second major cluster. All the tested Aspergillus strains were able to have a single PCR fragment amplified using the primer AspTef. TEF-1 DNA sequence bootstrap analysis with 1,000 replicates revealed two distinct groups. Additionally, the Aspergillus isolates were grouped into two different clusters with about 65% genetic similarity using ISSR-PCR analysis. The standard polymerase chain reaction was used to effectively amplify the Aopks, afl-A and omt-A genes in aflatoxigenic Aspergillus strains. Four Aspergillus strains used in this investigation were shown to generate aflatoxin B1. While, three Aspergillus stains showed ochratoxin genes. In conclusion, the results indicate significant differences in the fungal community between ecoregions and soil invertebrates. Moreover, mycotoxin detection and identification among Aspergillus isolates were elucidated. This study could shed light on the risk of mycotoxin contamination along the supply chain.

Investigation of the potential effects of firefighting water additives on soil invertebrates and terrestrial plants

The intensity and frequency of forest fires is increasing across the globe due to climate change. Additives are often added to make water more effective at extinguishing fire and preventing re-ignition. This study investigated the toxicity of nine different firefighting water additives to four species of soil invertebrates (Folsomia candida, Porcellio laevis, Porcellio scaber, and Trichorhina tomentosa) and two plant species (Agropyron cristatum and Raphanus sativus). Considerable variation in toxicity was observed among the firefighting products. The toxicity of individual products also varied considerably amongst the tested species. A hazard assessment was conducted by comparing the concentration of firefighting water additive that caused a 50% effect (LC50 or EC50) or a concentration that caused no effect (NOEC) to the concentration recommended by the manufacturer. At a rate of application representative of a forest firefighting scenario, most firefighting water additives tested in this study posed a hazard to F. candida and the three isopod species. The majority of products did not pose a risk to the two plant species included in this study. Consideration of the toxicity of firefighting water additives to terrestrial biota should be considered along with the efficacy of the product to fight fires when deciding which products to use.

Effects of Dietary Coffee on Feeding Parameters and Growth of Terrestrial Isopod, Porcellio laevis

Caffeine is considered the most widely consumed pharmacologically active drug. It is probably found in popular beverages (coffee, tea, soft drinks), as well as cocoa or chocolates-based goods. However, it has received a lot of attention there is still much to be learned with respect to its toxicology in animals. Terrestrial isopods are considered one of the most investigated invertebrate groups in soil ecotoxicology. The aim of this study was to evaluate the effect of different concentrations of coffee on feeding parameters and the growth of terrestrial isopod Porcellio laevis. Feeding parameters and growth efficiency were calculated and compared among treated isopod groups. The results revealed decreasing in food parameters such as consumption ratio, assimilation ratio, and egestion ratio in P. laevis treated with different concentrations of coffee. Also, decreasing growth efficiency for this isopod was noticed after exposure to different concentrations of coffee. These results indicate that high levels of caffeine may have toxic effects on P. laevis after a long period of exposure. Further research about the toxic effect of caffeine on isopods is needed.

Towards Study of UV-C Radiation Effect on Earthworms and Isopods Via Electron Microscopy

Background and Objective: Ultraviolet (UV)radiation is the most significant modifiable risk factor for eye and skin disorders especially skin cancer, atrophy, pigment shifts, and wrinkling in many living organisms. So, this study is based on the detection of the cumulative effects of UV-C radiation on the earthworms (as an alternative model for human skin) and isopods (as an alternative model for the eye) coupled with scanning electron microscopic analysis (SEM). This study was designed for the assessment of human health implications and for the planning of safety measures for human beings. Materials and Methods: Random samples of earthworms and isopods were collected from different areas. Ten earthworms (Lumbricus castaneus) and fifteen isopods (Porcellio laevis) per set were put in a plastic container and were placed in four groups: control and three UV-C treated groups. The groups were exposed to UV-C for (15 min/day, 30 min/day and 60 min/day) for three consecutive days using a Laminar Flow UV (254 nm). However, the control group was kept under laboratory conditions and without exposure to UV-C. Morphological changes of earthworms and isopods were examined using SEM. Results: Mild changes appeared after exposure of earthworms and isopods to UV-C for 15 min/day. These changes are maximized after 30 min/day. Complete disappearance of the cell junctions in earthworms with sloughed tissue as well accumulation of crusts between junctions of the compound eye in isopods were observed after exposure for 60 min/day. Conclusion: For the first time, SEM analysis was established to detect the influence of UV-C radiation on earthworms and isopods. It was found that prolonged exposure to UV-C radiation induced severe damage and an increase in the mortality rate for both earthworms and isopods.

Effect of Vermicompost and Isopod (Porcellio laevis) Fertilizers on The Emergence and Seedling Quality of Lettuce (Lactuca sativa var. capitata cv. Wismar)

A great number of insects play an essential role in stabilizing and sustainability of ecosystems. The terrestrial isopods are also important members of soil macrofauna in many habitats, and they are considered as an integral part of the decomposition process. Although the role of isopod in decomposing organic matter and recycling nutrients is very well known, there is no available scientific research or information dealing with the utilization of fertilizer obtained from it as the plant and seedling growing media or soil conditioner in agriculture production. The main goal of this study was to evaluate the usability of fertilizer obtained from a terrestrial isopod (Porcellio laevis) and the effect of vermicompost added into the growing media in the growing of lettuce seedlings. By this purpose, 10 different mixtures containing 1, 5, 10 and 20% of each fertilizer [including agricultural soil (control) and peat] as seedling growth media were used. According to results the differences among growing media in terms of emergence and seedling characteristics were not significant. However, the leaf number, fresh-dry shoot weight, and fresh-dry root weight of seedling in all mixtures were equal or higher than control. Results from the study suggest that the isopod fertilizer for the evaluation of agricultural organic wastes which are sometimes regarded as pollutants could be confidently used.

Foraging Bumblebees Selectively Attend to Other Types of Bees Based on Their Reward-Predictive Value

Simple SummarySocial information use is a widespread phenomenon in animals affecting various important aspects of behavior. Animals observe and copy the behavioral patterns of conspecifics and other species on the same trophic level in their own decision-making. Copying others is adaptive only when it is selective, otherwise running the risk of copying bad behavior. Thus, it would be important to know when and which individuals should be copied. We showed that bumblebees Bombus terrestris learn to attend to specific types of bees based on their learned value as information-providers about reward. Learned information was transferred across foraging contexts, representing a useful pathway for bees to acquire relevant information about unfamiliar floral resources that goes beyond conspecific social information use, extending to heterospecifics. Our findings indicate that the transmission of social information across species can be highly selective in response to learned value of the information provider, plausibly making the phenomenon adaptive.Using social information can be an efficient strategy for learning in a new environment while reducing the risks associated with trial-and-error learning. Whereas social information from conspecifics has long been assumed to be preferentially attended by animals, heterospecifics can also provide relevant information. Because different species may vary in their informative value, using heterospecific social information indiscriminately can be ineffective and even detrimental. Here, we evaluated how selective use of social information might arise at a proximate level in bumblebees (Bombus terrestris) as a result of experience with demonstrators differing in their visual appearance and in their informative value as reward predictors. Bumblebees were first trained to discriminate rewarding from unrewarding flowers based on which type of “heterospecific” (one of two differently painted model bees) was next to each flower. Subsequently, these bumblebees were exposed to a novel foraging context with two live painted bees. In this novel context, observer bumblebees showed significantly more social information-seeking behavior towards the type of bees that had predicted reward during training. Bumblebees were not attracted by paint-marked small wooden balls (moved via magnets) or paint-marked non-pollinating heterospecifics (woodlice; Porcellio laevis) in the novel context, indicating that bees did not simply respond to conditioned color cues nor to irrelevant social cues, but rather had a “search image” of what previously constituted a valuable, versus invaluable, information provider. The behavior of our bumblebees suggests that their use of social information is governed by learning, is selective, and extends beyond conspecifics.

Soil arthropods associated with sweetpotato crop (Ipomoea batata L.) in La Molina, Lima, Peru

Sweetpotato ( Ipomoea batata L.) is an economically important crop grown in Peru. The present study aimed to determine the soil arthropods associated with sweetpotato and its relative abundance in sweetpotato production fields in La Molina, Lima, Peru. Evaluations were conducted at Universidad Nacional Agraria La Molina, from February to August 2017. Samples were collected using pitfall traps and examined at the Klaus Raven Buller Entomology Museum. Soil morphospecies were extracted and separated from collected samples and then counted, recorded and identified. They were also admitted to the Entomology Museum collection. Eighty morphospecies in the classes Collembola, Insecta, Malacostraca, Arachnida and Chilopoda of phylum Arthropoda were recorded. Within the Collembola class, Entomobryidae was the most abundant family; within Insecta, Gryllus spp. (Gryllidae); within Malacostraca, Porcellio laevis (Porcellionidae); within Arachnida, Theridion volubile (Theridiidae) of the order Aranea; and within Chilopoda, the order Lithobiomorpha. By understanding the diversity of arthropods, it may inform future measures and improve control of pests by taking into consideration the soil arthropods among which important beneficial natural enemies could be found.

New records of exotic species of Oniscidea (Crustacea: Isopoda) from northern Mexico

To date 86 species of 33 genera and 16 families of Oniscidea have been recorded in Mexico. Collections of 4 academic institutions and recent field materials were revised. From 1,820 specimens, 1,417 (77.6%) were determined to belong to 6 exotic forms. A taxonomic account and a species identification key with SEM plates of these exotic entities are presented. For morphological analysis we used light and SEM microscopy. The molecular identity of 5 of the 6 forms was examined through cytochrome oxidase 1 gene (mtDNA) analyses. The exotic species determined are: Armadillidae, Cubaris murina; Armadillidiidae, Armadillidium vulgare; Porcellionidae, Agabiformius lentus, Porcellio laevis, P. scaber, and Porcellionides pruinosus. The exotic oniscideans were recorded from urban, rural and natural (riparian) zones in 15 states of northern Mexico, including the first formal records in Aguascalientes,Chihuahua, Durango, and Zacatecas. Armadillidium vulgare, P. laevis, and P. pruinosus often co-occurred and are the most widely distributed species in this region. Although most of the material examined was recorded from urban zones(> 50% of studied sites), A. vulgare and P. laevis were also found in riparian areas (natural zones), yet P. pruinosus was recorded mainly from riparian areas (60% of 45 lots examined).

Physiological and histopathological responses of Porcellio laevis (Isopoda, Crustacea) as indicators of metal trace element contamination

This study was designed to assess the impact of the mixture of cadmium (Cd) and zinc (Zn) on the bioaccumulation and the ultrastructural changes in the hepatopancreas of Porcellio laevis (Latreille, 1804) after 4 weeks of exposure to contaminated Quercus leaves under laboratory conditions. For each metal, four concentrations were used with four replicates for each concentration. Metal concentrations in the hepatopancreas and the rest of the body were determined using atomic absorption spectrometry. From the first week until the end of the experiment, a weight gain in P. laevis was observed particularly between the first and the end of exposure from 93.3 ± 18.22 mg fw to 105.22 ± 16.16 mg fw and from 106.4 ± 22.67 mg fw to 125.9 ± 23.9 mg fw for Mix1 and Mix4, respectively. Additionally, the determined metal trace elements (MTE) concentrations in the hepatopancreas were considerably higher compared to those in the rest of the body and seem to be dose-dependent. Using transmission electron microscopy (TEM), some alterations were highlighted in the hepatopancreas. The main observed alterations were (a) the destruction of the microvilli border in a considerable portion of cells, (b) the increase of the lipid droplets with different shapes and sizes, (c) the increase in the number of the mitochondria, and (d) the appearance of TE in the form of B-type granules. The obtained results confirmed the ability of P. laevis to deal with high amounts of MTE, suggesting its possible use in future soil's biomonitoring programs.

Effet du champ magnétique statique sur les préférences écologiques de trois isopodes terrestres (Isopoda, Oniscidea)

Résumé Dans ce travail, nous avons analysé les préférendums photique, thermique, hygrique et granulométrique de trois espèces d’isopodes terrestres : Armadillidium vulgare (Latreille, 1804), A. granulatum (Brandt, 1833), et Porcellio laevis Latreille, 1804 en réponse à un champ magnétique statique (CMS) (0 Hz, 200 mT). Les animaux exposés au CMS montrent une augmentation significative du nombre des spécimens photophiles et une diminution significative des animaux photophobes. Ces cloportes montrent aussi une diminution significative des spécimens préférant le froid et une augmentation significative de ceux préférant le compartiment chaud. Cette exposition au CMS cause un inversement très significatif du choix préférentiel du compartiment humide au compartiment sec chez A. vulgare et P. laevis, alors que ce changement n’est pas significatif chez A. granulatum. Cette même exposition a entrainé une nette perturbation du choix de la granulométrie du substratum, en particulier pour le gravier chez A. vulgare.

Terrestrial isopods as bioindicators for environmental monitoring in olive groves and natural ecosystems

ABSTRACTTerrestrial isopods (Crustacea: Isopoda: Oniscidea) are an important component of biodiversity as they constitute useful bioindicators for monitoring environmental quality in a variety of natural and agricultural ecosystems. In the present study, the predictive strength of several important components of biodiversity (e.g. herbaceous and woody plants, etc.) and agro-environmental factors for isopod species richness in each management system of olive groves and a natural ecosystem in central Greece was investigated. Our study highlights an increase in isopod species richness with increasing air humidity, woody plant species richness and soil organic matter in organic olive groves. It is noteworthy that woody plant species richness could be utilised as the best candidate for monitoring isopod species richness. In the conventional olive groves, isopod species richness decreases possibly due to herbicide and inorganic fertiliser application. In abandoned olive groves, isopod species richness increases with increasing soil plant litter and pH. Moreover, soil organic matter has been proved to be a positive indicator of isopod species richness in maquis ecosystems. The species Porcellio laevis can be regarded as an indicator for organic olive groves. Conclusively, this paper contributes to the integration of biodiversity conservation with ecologically sustainable agriculture, conservation of agroecosystem and natural ecosystem services and preserving landscape.

Effects of Heavy Metals Artificial Contamination on Porcellio laevis (Latreille, 1804) (Crustacea: Isopoda: Oniscidea)

This study aimed at determining the competition of cadmium (Cd), lead (Pb), zinc (Zn) and copper (Cu) on their assimilation, on the food consumption and the growth of terrestrial isopod Porcellio laevis. Individuals were exposed to artificially contaminated litter of Quercus for 4weeks and were weekly weighed. At the end of the experiment, the concentration of Cd, Pb, Zn and Cu in individuals were measured by atomic absorption spectrometry. Biological parameters such as growth, and bioaccumulation factor (BAF) were calculated and results from the various treatments were compared. Depending on metals, weight loss or gain were recorded for isopods during the four weeks of exposure. A weight loss was measured on individuals exposed to Cd-contaminated litter whereas a weight gain was highlighted for those exposed to the Zn-contaminated litter. BAF values revealed that P. laevis was macroconcentrator of Zn and Cu and deconcentrator of Cd and Pb.

Changes in life history characteristics of Porcellio laevis (Isopoda: Oniscidea) along a cadmium pollution gradient in Sfax (Central Tunisia)

This study aimed to determine the effect of cadmium pollution on some life history traits of Porcellio laevis populations sampled along a contamination gradient in the region of Sfax (central Tunisia). To characterize each population, woodlice were collected in the spring and parameters such as the number of individuals, sex-ratio, body length and cephalothorax width of the different categories of individuals were determined. Since the sampling period coincided with the reproduction period of the species, number and diameter of eggs, embryos, and mancas were counted and measured for ovigerous females of each of the studied population. Relative growth was estimated using a morphometric relationship between the body length and the cephalothorax width to determine the type of relationship (isometric/allometric). The number of eggs, embryos and mancas varied between the sampled populations and ranged between 13.25 ± 7.18 and 58.85 ± 36.37; 25 ± 8.71 and 40.9 ± 11.47; 11.5 ± 7.77 and 29 mm, respectively. The mean size of eggs, embryos and mancas ranged between 0.491 ± 0.077 and 0.558 ± 0.098 mm, 0.697 ± 0.070 and 0.918 ± 0.206 mm, and 0.945 ± 0.248 and 1.554 ± 0.236 mm, respectively. Body length, cephalothorax width, eggs and embryos sizes, were lower in the population sampled from the most polluted site compared to the other populations. Additionally, based on the Pearson’s correlation, negative and non-significant correlations were found between the number and the size of the different reproductive stages (eggs, embryos and mancas), and cadmium soil content. The morphometric parameters showed a significant correlation between the body length and the cephalothorax width, and globally a negative allometry was observed.