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Artificial light at night (ALAN), also known as light pollution, is a growing environmental problem worldwide. However, only a few studies have examined whether soil organisms that search for food at the surface at night can be affected by ALAN. We investigated the effects of ALAN on the above-ground foraging activity of anecic earthworms (Lumbricus terrestris), on the soil water infiltration and on the germination and growth of a cover crop (Phacelia tanacetifolia). In a full-factorial greenhouse experiment, we tested four factors: ALAN (about 5 lx during the night vs. total darkness), earthworms (two specimens vs. none), plant species (Phacelia alone vs. mixed with ragweed Ambrosia artemisiifolia) and sowing depth (surface-sown vs. sown in 5 cm depth). Data were analysed using multifactorial ANOVAs. Earthworms removed 51% less surface litter under ALAN than under dark conditions. ALAN had no effect on Phacelia germination but resulted in increased height growth and biomass production when the seeds were buried. Earthworms reduced Phacelia germination and biomass production. ALAN reduced water leaching through the experimental units, probably due to interactions between the subsurface casts and plant roots. We conclude that ALAN, as emitted from streetlights, can lead to complex ecological effects in ecosystems that merit further investigation. [ABSTRACT FROM AUTHOR]

AbstractHaemorrhagic shock is a leading cause of death worldwide. Blood transfusions can be used to treat patients suffering severe blood loss but donated red blood cells (RBCs) have several limitations that limit their availability and use. To solve the problems associated with donated RBCs, several acellular haemoglobin-based oxygen carriers (HBOCs) have been developed to restore the most important function of blood: oxygen transport. One promising HBOC is the naturally extracellular haemoglobin (i.e. erythrocruorin) of Lumbricus terrestris (LtEc). The goal of this study was to maximise the portability of LtEc by lyophilising it and then testing its stability at elevated temperatures. To prevent oxidation, several cryoprotectants were screened to determine the optimum formulation for lyophilisation that could minimise oxidation of the haem iron and maximise recovery. Furthermore, samples were also deoxygenated prior to storage to decrease auto-oxidation, while resuspension in a solution containing ascorbic acid was shown to partially reduce LtEc that had oxidised during storage (e.g. from 42% Fe3+ to 11% Fe3+). Analysis of the oxygen equilibria and size of the resuspended LtEc showed that the lyophilisation, storage, and resuspension processes did not affect the oxygen transport properties or the structure of the LtEc, even after 6 months of storage at 40 °C. Altogether, these efforts have yielded a shelf-stable LtEc powder that can be stored for long periods at high temperatures, but future animal studies will be necessary to prove that the resuspended product is a safe and effective oxygen transporter in vivo.

This study aimed to investigate the carbon to nitrogen ratio (C/N) in vermicomposts produced from mixtures of cabbage, beans, and tea remnants combined with cardboard at a 1:1 ratio, totaling 2 kilograms, using two different types of worms: Lumbricus terrestris and Eisenia fetida. The results indicated that vermicompost produced by Eisenia fetida exhibited a significant decrease in C/N ratio by 18.60, whereas that produced by Lumbricus terrestris had a C/N ratio of 20.723. Regarding interactions, the highest initial C/N ratio among cabbage remnants, irrespective of worm type, was 25.000, whereas the lowest ratio after processing was 1.936 for tea remnants, showing significant differences. Across all remnants, there was a consistent decrease in C/N ratio post-processing, with cabbage remnants exhibiting the highest initial ratio of 25.00 before earthworm addition and tea remnants showing the lowest ratio of 8.530 after earthworm processing, indicating significant variation. [ABSTRACT FROM AUTHOR]

Earthworms are ecosystem engineers, owed to their ability to modify the soil resources for other organisms through induction of important changes in the state of the biotic and abiotic soil components. They are very sensitive small invertebrate animals to agricultural pesticides, as well as the best soil pollution bioindicators. Thus, the present study aimed to assess the effects of an herbicide (Linuron) induced changes in major biochemical markers (the content of total protein, total carbohydrate, total lipid, and catalase activity) in Lumbricus terrestris. Statistical analysis of data revealed significant differences in the content of total proteins, lipids, and total carbohydrates, and no significant difference in catalase activity between control and Linurontreated L. terrestris over the three exposure periods (24 h, 48 h, and 72 h) and the three doses used (250 µg, 500 µg, and 1000 µg). Moreover, correlation coefficient analysis showed a positive correlation between protein and lipid contents (r = 0.50, r2 = 50%) during all three exposure periods. Conclusively, this study suggested the determined metabolites as a valuable tools in the environmental risk assessment, and the understanding of the process underlying Linuron induced oxidative stress in L. terrestris. [ABSTRACT FROM AUTHOR]

Biodegradable polylactic acid (PLA) mulch has been developed to replace conventional polyethylene (PE) mulch in agriculture as a response to growing concerns about recalcitrant plastic pollution and the accumulation of microplastics (MPs) in soil. Cadmium is a significant soil pollutant in China. MPs have been shown to adsorb metals. In this study the earthworm Lumbricus terrestris was exposed to either Cd (1.0–100 mg / kg) or MPs (PE and PLA, 0.1–3 % w / w), or a combination of the two, for 28 days. Cd bioavailability significantly decreased in the presence of MPs. In particular, at the end of the experiment, PLA treatments had lower measured Cd concentrations in both earthworms (2.127–29.24 mg / kg) and pore water (below detection limits - 0.1384 mg /L) relative to PE treatments (2.720–33.77 mg / kg and below detection limits - 0.2489 mg / L). In our adsorption experiment PLA MPs adsorbed significantly more Cd than PE MPs with maximum adsorption capacities of 126.0 and 23.2 mg / kg respectively. These results suggest that the PLA MPs reduce earthworm exposure to Cd relative to PE by removing it from solution and reducing its bioavailability.

The erythrocruorin of Lumbricus terrestris (LtEc) is a relatively large macromolecular assembly that consists of at least four different hemoglobin subunits (A, B, C, and D) and four linker subunits (L1, L2, L3, and L4). The complexity and stability of this large structure make LtEc an attractive hemoglobin-based oxygen carrier that could potentially be used as a substitute for donated red blood cells. However, the sequences of the LtEc subunit sequences must be determined before a scalable recombinant expression platform can be developed. The goal of this study was to sequence the L. terrestris genome to identify the complete sequences of the LtEc subunit genes. Our results revealed multiple homologous genes for each subunit (e.g., two homologous A globin genes; A1 and A2), with the exception of the L4 linker. Some of the homologous genes encoded identical peptide sequences (C1 and C2, L1a and L1b), while cDNA and mass spectrometry experiments revealed that some of the homologs are not expressed (e.g., A2). In contrast, multiple sequences for the B, D, L2, and L4 subunits were detected in LtEc samples. These observations reveal novel degeneracy in LtEc and other annelids, along with some new revisions to its previously published peptide sequences. [Display omitted] • A draft (partial) sequence of the earthworm genome was obtained. • Multiple copies of LtEc genes were discovered, including previously unknown sequences. • Use of NGS and LC-MS to quantify gene expression. • Degeneracy of the subunit sequences was confirmed. [ABSTRACT FROM AUTHOR]

Abstract Background Artificial light at night, also referred to as light pollution (LP), has been shown to affect many organisms. However, little is known about the extent to which ecological interactions between earthworms and plants are altered by LP. We investigated the effects of LP on anecic earthworms (Lumbricus terrestris) that come to the surface at night to forage and mate, and on the germination and growth of the invasive and allergenic ragweed (Ambrosia artemisiifolia). In a full factorial pot experiment in the greenhouse, we tested four factors and their interactions: LP (5 lux vs. 0 lux at night), earthworms (two individuals vs. none), plant species (seeding of ragweed only vs. mixed with Phacelia seeds) and sowing depth (seed placed at the surface vs. in 5 cm depth). Data were analysed using Generalized Linear (Mixed) Models and multifactorial ANOVAs with soil parameters as covariates. Results Light pollution reduced earthworm surface activity by 76% as measured by casting activity and toothpick index; 85% of mating earthworms were observed in the absence of LP. Light pollution in interaction with earthworms reduced ragweed germination by 33%. However, LP increased ragweed height growth by 104%. Earthworms reduced ragweed germination especially when seeds were placed on the soil surface, suggesting seed consumption by earthworms. Conclusions Our data suggest that anecic earthworms are negatively affected by LP because reduced surface activity limits their ability to forage and mate. The extent to which earthworm-induced ecosystem services or community interactions are also affected by LP remains to be investigated. If the increased height growth of ragweed leads to increased pollen and seed production, it is likely that the competition of ragweed with field crops and the risks to human health will also increase under LP.

Artificial light at night (ALAN), also known as light pollution, is a growing environmental problem worldwide. However, only a few studies have examined whether soil organisms that search for food at the surface at night can be affected by ALAN. We investigated the effects of ALAN on the above-ground foraging activity of anecic earthworms (Lumbricus terrestris), on the soil water infiltration and on the germination and growth of a cover crop (Phacelia tanacetifolia). In a full-factorial greenhouse experiment, we tested four factors: ALAN (about 5 lx during the night vs. total darkness), earthworms (two specimens vs. none), plant species (Phacelia alone vs. mixed with ragweed Ambrosia artemisiifolia) and sowing depth (surface-sown vs. sown in 5 cm depth). Data were analysed using multifactorial ANOVAs. Earthworms removed 51% less surface litter under ALAN than under dark conditions. ALAN had no effect on Phacelia germination but resulted in increased height growth and biomass production when the seeds were buried. Earthworms reduced Phacelia germination and biomass production. ALAN reduced water leaching through the experimental units, probably due to interactions between the subsurface casts and plant roots. We conclude that ALAN, as emitted from streetlights, can lead to complex ecological effects in ecosystems that merit further investigation.

We present a genome assembly from an individual Lumbricus terrestris (the common earthworm; Annelida; Clitellata; Haplotaxida; Lumbricidae). The genome sequence is 1,056.5 megabases in span. Most of the assembly is scaffolded into 18 chromosomal pseudomolecules. The mitochondrial genome has also been assembled and is 15.93 kilobases in length.

Earthworms are effective bio-indicators of biodiversity, soil quality and the environmental impact on cropping systems. Therefore, this study was conducted to assess the toxicological effect of Acetamiprid, a widely used insecticide by farmers in the region of Souk-Ahras (Algeria), on a biological model named Lumbricus terrestris using seven increasing concentrations 0, 5, 7, 9, 12.5, 25 and 50 mg/500 mg soil for four control periods; 24, 48, 72 and 96 hours. The physicochemical soil analysis indicated that the soil pH was strongly alkaline, and the pH water and pH KCl were respectively 8.52 and 7.72. The soil texture was sandy loam with a high level of organic matter (OM = 12.9%). In addition, the LC50 and LC90 values were remarkably decreased (LC50 = 12.4, 10, 7.30 and 6.69/500 mg soil; LC90 = 18.52, 14.21, 9.50, 9.15 mg/500 mg soil, corresponding respectively for each LC values to the four exposure periods 24, 48, 72 and 96 hours). Furthermore, no significant change was noticed in body weight and growth of earthworms treated with Acetamiprid at various concentrations. The mortality rate was concentration-dependent; increased with increasing concentration, and this was supported by the histopathological observations showing cellular alterations in the epidermis and muscle fibers. Additionally, treatment with Acetamiprid at high concentrations caused marked morphological abnormalities in the earthworms as evidenced by the winding of the body, loss of pigmentation, cut of the posterior part, lesions, or bloody wounds. [ABSTRACT FROM AUTHOR]

Nearly the entire North American and European supply of the bait worm Lumbricus terrestris is hand-picked from southwestern Ontario dairy farms. This "Canadian nightcrawler" industry is largely a cash business that operates 'underground,' with very little information about how the 'worm pickers' engage with dairy farmers and the cash rents they receive. In this paper, I provide a brief background of the industry and how it came to rely on Ontario dairy farms as sites of L. terrestris production. I describe the three prominent arrangements dairy farmers have with pickers that correspond to rental rates that range between $200 and $1500 CND per acre. I then compare these prices with average farmland rental rates in the region and estimated net income from growing field crops typically planted by dairy farmers (corn, soy, alfalfa/hay). By comparing this information, I suggest L. terrestris is the most profitable 'crop' that southwestern Ontario dairy farmers could grow, followed by a discussion of why more farmers decide not to engage with the industry. [ABSTRACT FROM AUTHOR]

The conversion from conventional tillage to no‐tillage soil management practices is generally associated with an improvement in aggregate stability and anecic earthworm populations. We worked with UK farmers who measured Lumbricus terrestris midden area (%) and earthworm numbers associated with middens compared to the general soil. They found that middens covered up to 42% of the soil surface. Middened soil (i.e., soil underlying the middens) was associated with significantly more earthworms than the general soil (i.e., non‐middened soil) in agreement with research from scientific field trials. We compared the biophysical properties of middened soil to general soil across an experimental field trial recently converted to no‐tillage soil management practices. We measured water‐stable aggregation, soil porosity at scales relevant to water storage and gas diffusion and invertebrate feeding activity. Middened areas covered up to 13% of the field trial and were associated with significantly improved aggregate stability and porosity compared to the general soil. Our findings highlight the importance of considering middens when surveying soil quality and health in arable systems. [ABSTRACT FROM AUTHOR]

The importance of earthworms for soil functioning is widely accepted and is mainly linked to their burrowing, feeding and casting behaviours. However, our knowledge of earthworm behavior is still limited by the lack of efficient and easy-to-use methods. In this work, we describe and test a new marker of earthworm bioturbation. Dense particles of tungsten, visible in X-ray images, were located at a certain depth in repacked soil cores inoculated by either Lumbricus terrestris or Aporrectodea caliginosa , alone or in combination. This marker was compared to the classical luminophore method (i.e. colored sand particles) generally used in aquatic ecology. The dynamics of both the burrow systems and the casting activities was followed using X-ray tomography every two weeks for a period of 10 weeks. Below ground casting activities could be assessed since parts of the casts excreted by the earthworms were marked by tungsten and appeared white in the images. The time dynamics of both burrow and cast productions were almost linear and significantly influenced by the earthworm species and the presence of litter. As expected, L. terrestris created larger (up to 50 cm3) and deeper burrow systems and made fewer macropores compared to A. caliginosa. Surprisingly, both species were equally influenced by the presence of litter, and this highlighted their behavioral plasticity. For example, A. caliginosa decreased by 32 % the volume of burrows in the presence of litter and the resulting burrow system was significantly shallower which showed that this endogeic species is indeed able to partly feed on surface litter. The use of tungsten particles is a promising new tool to accurately characterize the casting activities of earthworms in the soil and to study behavioral plasticity under the influence of environmental factors. • Tungsten (W) particles were tested s a new bioturbation marker visible in X-ray. • When W mixed with soil is egested by earthworms, casts appeared white in X-ray images. • W had no short-term toxicity for Lumbricus terrestris or Aporrectodea caliginosa. • Litter presence at the soil surface influences bioturbation dynamics for both species. [ABSTRACT FROM AUTHOR]

Soil aggregates are important for soil fertility and earthworms can support aggregate formation and stability during gut passage, burrowing activity and secretion of polysaccharides. To determine these effects in different soil tillage systems, soil properties, and the earthworm community associated with Lumbricus terrestris (Linnaeus, 1758) were evaluated in two long-term field experiments using plough, cultivator, or no-till. The aim was to investigate effects of earthworm populations on soil aggregate stability and to evaluate three methods, namely: water stable aggregate (WSA) index, MOULDER (formerly SLAKES) and SlakeLight. The WSA method wet-sieves aggregates for 3 min in distilled water and records mass of the dispersed aggregates. MOULDER uses a smartphone application to measure an increase in area of dispersed soil submerged in distilled water to measure slaking, while SlakeLight analyses light transmission corresponding to the area covered by the soil material. Soil samples were collected in autumn at three levels: i) middens, ii) 5 cm radius around burrows of L. terrestris (burrow-midden-complex), and iii) in bulk soil without burrows of L. terrestris. All samples were hand-searched for earthworms or air-dried for soil aggregate stability analyses. The hypothesis tested was that there is a gradient of earthworm worked soil, such that the level of earthworm activity away from a L. terrestris burrow decreases so that: midden > burrow-midden-complex > bulk soil. Total earthworm abundance (individuals level−1 ± standard deviation), mostly endogeic earthworms, was 3-times higher in the burrow-midden-complex (4.3 ± 2.7) than bulk soil for cultivator and doubled for burrow-midden-complex under a ploughing regime (3 ± 2.1), while no-till was only slightly increased (4.6 ± 2). With rising earthworm numbers, aggregate stability increased, with a higher effect for bulk soil than for burrow-midden-complex. At both sites, MOULDER identified a more stable soil in middens than in bulk soil, while other methods were not so discriminating in their outcomes of middens. However, WSA was more sensitive to interactions of soil tillage × earthworm abundance than SlakeLight or MOULDER and showed that ploughed soil and bulk soil aggregates stabilised the most with increasing earthworm activity. Comparison of the three methods showed that all can be used for earthworm-processed soil, but that selection of the method should depend on the research questions and on resource availability. [ABSTRACT FROM AUTHOR]

Biodegradable polylactic acid (PLA) mulch has been developed to replace conventional polyethylene (PE) mulch in agriculture as a response to growing concerns about recalcitrant plastic pollution and the accumulation of microplastics (MPs) in soil. Cadmium is a significant soil pollutant in China. MPs have been shown to adsorb metals. In this study the earthworm Lumbricus terrestris was exposed to either Cd (1.0–100 mg / kg) or MPs (PE and PLA, 0.1–3 % w / w), or a combination of the two, for 28 days. Cd bioavailability significantly decreased in the presence of MPs. In particular, at the end of the experiment, PLA treatments had lower measured Cd concentrations in both earthworms (2.127–29.24 mg / kg) and pore water (below detection limits - 0.1384 mg /L) relative to PE treatments (2.720–33.77 mg / kg and below detection limits - 0.2489 mg / L). In our adsorption experiment PLA MPs adsorbed significantly more Cd than PE MPs with maximum adsorption capacities of 126.0 and 23.2 mg / kg respectively. These results suggest that the PLA MPs reduce earthworm exposure to Cd relative to PE by removing it from solution and reducing its bioavailability. [Display omitted] • Realistic levels of MP in soils did not impact earthworm mortality or weight change. • The presence of MPs decreased Cd concentrations in both earthworms and pore water. • PLA MPs decreased Cd accumulation in earthworms relative to PE MPs. • PLA MPs adsorbed significantly more Cd than PE MPs. [ABSTRACT FROM AUTHOR]

Agronomic factors can affect mycotoxin contamination of maize, one of the most produced cereals. Maize is usually harvested at 18% moisture, but it is not microbiologically stable until it reaches 14% moisture at the drying plants. We studied how three agronomic factors (crop diversification, tillage system and nitrogen fertilization rate) can affect fungal and mycotoxin contamination (deoxynivalenol and fumonisins B1 and B2) in maize at harvest. In addition, changes in maize during a simulated harvest-till-drying period were studied. DON content at harvest was higher for maize under intensive tillage than using direct drilling (2695 and 474 μg kg−1, respectively). We found two reasons for this: (i) soil crusting in intensive tillage plots caused the formation of pools of water that created high air humidity conditions, favouring the development of DON-producing moulds; (ii) the population of Lumbricus terrestris, an earthworm that would indirectly minimize fungal infection and mycotoxin production on maize kernels, is reduced in intensive tillage plots. Therefore, direct drilling is a better approach than intensive tillage for both preventing DON contamination and preserving soil quality. Concerning the simulated harvest-till-drying period, DON significantly increased between storage days 0 and 5. Water activity dropped on the 4th day, below the threshold for DON production (around 0.91). From our perspective, this study constitutes a step forward towards understanding the relationships between agronomic factors and mycotoxin contamination in maize, and towards improving food safety. [ABSTRACT FROM AUTHOR]

Although awareness of the influence of earthworms on soil seed banks in Canadian forests is growing, there have been few direct field measurements. We used a novel pairing of field-collected earthworms from a central Great Lakes forest in Ontario with a laboratory seed egestion assay to obtain a snapshot of the number of seeds passing through earthworms compared with seeds found in the surrounding soil. We identified a pool of seeds egested by earthworms that accounted for 2.4% of all seeds found in the earthworms and the top 0-10 cm of soil. Individual earthworms contained 0-5 seeds. The large-bodied adult anecic non-native Dew Worm or Common Nightcrawler (Lumbricus terrestris) egested a disproportionate number of seeds for its abundance (50% of egested seeds from 17% of earthworms), but smaller earthworms were also an important source of egested seeds (the other 50%). This small-scale proof-of-concept study demonstrates a method of directly measuring earthworm-seed interactions in the field. It can also detect seeds egested by earthworms below ground that would otherwise be missed by other seed accounting methods and it highlights the importance of granivory by non-surface casting earthworms. [ABSTRACT FROM AUTHOR]

Phasmarhabditis hermaphrodita is a parasitic nematode of terrestrial gastropods that has been formulated into a successful biological control agent used on farms and gardens across Europe. There are reports of members of the Phasmarhabditis genus affecting the survival of non-target organisms under lab conditions e.g. earthworms. Therefore, we exposed two species of earthworm (Lumbricus terrestris and Eisenia hortensis) and insect (Galleria mellonella and Tenebrio molitor) to a range of doses of P. californica (0, 30 and 150 nematodes per cm2). P. californica did not affect earthworm or insect survival emphasising these nematodes are gastropod parasites that pose no risk to earthworms or insects (based on laboratory trials). [ABSTRACT FROM AUTHOR]

The soil microbiome, which is shaped by gut-related activities of earthworms, is affected by microplastic contamination. However, the influence of microplastics on earthworm gut and cast microbiomes has been poorly explored. Here, we investigated the influence of microplastics (1% in soil, w/w) on soil physicochemical properties and bacterial communities during gut passage and cast aging of Lumbricus terrestris. Microplastics used in agricultural film production were selected, i.e., low density polyethylene, polylactic acid and polybutylene adipate terephthalate (PBAT). Different niches, including pre-ingestion soil, gut content and aged casts (from 0 to 180 days), were studied. Results showed that microplastics possibly enhanced the gut passage-derived difference between pre-ingestion soil and fresh cast in terms of pH, ammonium, nitrate and nitrite, and dissolved organic carbon. But such effects mostly faded out after 180 days of aging. The composition, as well as the alpha and beta diversity of both the total (DNA) and active (RNA) bacterial communities were decisively shaped by their niche (R2: 0.22–0.63, p < 0.001, PERMANOVA), rather than the presence/absence or the types of MPs. Nevertheless, biomarkers indicative of PBAT treatment were identified, and functional prediction for the active community showed that bacterial communities of this treatment had higher potentials for hydrocarbon degradation (4.9–7.8 times that of the microplastic-free treatment in gut and aged casts). We also identified a "Soil-related core community" and a "Gut-related core community" (contributing to 39.2%–50.2% of the cast microbiome), which possibly neutralized microplastic impacts and maintained the structure and function of bacterial communities during the soil–gut–cast transit. Our findings indicate that the tested microplastics exerted a minor influence on the bacterial communities during the cast aging process, microplastics in aged casts might not necessarily have significant additional influence on the soil microbiome when they are incorporated into soils. Future studies testing different soils, polymers, and earthworm species, under field conditions are recommended to help enhance current knowledge of the influence of microplastics on earthworm cast microbiomes. [Display omitted] • Microplastics (MPs) influence on the aging of earthworm casts was studied. • MPs affected the physicochemical properties of fresh casts but not in the long term. • PBAT MPs had minor influence on the active community (RNA). • Soil- and Gut-related core communities were likely to buffer the impacts of MPs. • MP-containing casts may not cause additional effects on the soil microbiome. [ABSTRACT FROM AUTHOR]

Soil-associated invertebrates which are coprophagic are capable of acting as paratenic hosts for Toxocara species larvae eggs. The aim of the present study was to assess the role of Lumbricus terrestris earthworms as potential intermediate host for Toxocara species. A total of 240 earthworms were collected from the public places in four areas of Karaj, Alborz Province, Iran. The subjects of the study were digested to detect Toxocara species using microscopy and molecular analyses. Toxocara larvae and larval eggs were recovered from 1.7% (4/240) of the sampled earthworms. The recovery rate in Shah'Abbasi and Talaghani regions in the studied areas was higher than that of the other regions. In the mentioned area, 8.3% (4/48) of earthworms were revealed to be positive for Toxocara species by microscopic observation and only one was confirmed to be positive for Toxocara canis by polymerase chain reaction (PCR). This is the first molecular report of Toxocara canis infective larvae in Lumbricus terrestris earthworms that could be demonstrated in common environment.

Haemorrhagic shock is a leading cause of death worldwide. Blood transfusions can be used to treat patients suffering severe blood loss but donated red blood cells (RBCs) have several limitations that limit their availability and use. To solve the problems associated with donated RBCs, several acellular haemoglobin-based oxygen carriers (HBOCs) have been developed to restore the most important function of blood: oxygen transport. One promising HBOC is the naturally extracellular haemoglobin (i.e. erythrocruorin) of Lumbricus terrestris (LtEc). The goal of this study was to maximise the portability of LtEc by lyophilising it and then testing its stability at elevated temperatures. To prevent oxidation, several cryoprotectants were screened to determine the optimum formulation for lyophilisation that could minimise oxidation of the haem iron and maximise recovery. Furthermore, samples were also deoxygenated prior to storage to decrease auto-oxidation, while resuspension in a solution containing ascorbic acid was shown to partially reduce LtEc that had oxidised during storage (e.g. from 42% Fe 3+ to 11% Fe 3+ ). Analysis of the oxygen equilibria and size of the resuspended LtEc showed that the lyophilisation, storage, and resuspension processes did not affect the oxygen transport properties or the structure of the LtEc, even after 6 months of storage at 40 °C. Altogether, these efforts have yielded a shelf-stable LtEc powder that can be stored for long periods at high temperatures, but future animal studies will be necessary to prove that the resuspended product is a safe and effective oxygen transporter in vivo .

Introduced seed dispersers can shift seed predation dynamics in native species, impacting native plant establishment and spread. We studied the effect of the non‐native earthworm, Lumbricus terrestris, on seed loss dynamics in the large‐seeded native annual, Ambrosia trifida (giant ragweed), an expanding agricultural weed whose seeds are heavily predated by mice. Lumbricus terrestris may protect seeds against rodent predation by caching them in its burrows from which seedlings can emerge unharmed; however, little is known about the ability of earthworms to compete with rodents for seeds. We investigated this interaction and how environmental factors affected the competitive outcome.In a 2‐year field study, we analysed relative rates of seed removal by earthworms and mice for seeds dispersed at various times in habitats that varied in vegetative cover.Species‐specific responses to environmental conditions drove variation in the share of seeds taken by earthworms versus mice, with earthworms gaining relatively more seeds under warmer, wetter conditions and in low plant cover habitats, and mice obtaining more seeds under colder, drier conditions and in high cover habitats.Environmental factors also determined which competitor accessed seeds first, and this conferred a competitive advantage that was compounded over time.Earthworms cached some seeds under all experimental conditions, suggesting that L. terrestris can act mutualistically with giant ragweed in diverse environments.Synthesis and applications. Our results support the hypothesis that the non‐native earthworm Lumbricus terrestris behaves as a seed dispersal mutualist for the native annual giant ragweed by caching its seeds in its burrows, thereby reducing their availability to rodent seed predators. The data also support the view that interactions among the environment and competing seed predators determine the fate of seed pools in response to species‐specific environmental preferences. In crop fields where L. terrestris is abundant, additional efforts to prevent giant ragweed seed return may be warranted due to the likelihood that earthworms will increase giant ragweed soil seed pools. Lumbricus terrestris is expanding its range throughout temperate regions and may similarly affect secondary seed dispersal and seed predation dynamics of large‐seeded species in other plant communities. [ABSTRACT FROM AUTHOR]

The role of below-ground interactions between microbial biocontrol agents and soil fauna for combatting soil-borne plant diseases have not been studied sufficiently. This study tested the hypothesis that the beneficial bacterium Bacillus velezensis UCMB5113 and the anecic earthworm Lumbricus terrestris positively influence health and growth of peas (Pisum sativum L.) infested with the pathogen Aphanomyces euteiches causing root-rot disease. A greenhouse fully factorial experiment studied the effects of A. euteches, B. velezensis and L. terrestris on the emergence, growth and health of pea plants. The factors B. velezensis and L. terrestris resulted in taller plants (p = .003 and p = .030). B. velezensis treatment resulted in a higher biomass of shoots and roots (p ≤ .001 and p = .005). The effects increased with the presence of both factors (p = .036). Earthworms reduced the disease symptoms significantly (p = .032). The decreased disease symptoms caused by the earthworms might be due to the consumption of A. euteiches (direct effect) as well as soil disturbance (indirect effect). Interactions between the microorganisms added and the earthworms were shown. B. velezensis and L. terrestris can be useful for enhancement of plant growth and for biological control of root-rot in peas.

Non-native earthworms can alter ecosystems by modifying soil structure, depredating seeds and seedlings, and consuming soil organic matter, yet the initial responses of plant communities to earthworm invasions remain poorly understood. We assessed the effect of non-native earthworms on seedling survival during germination and after establishment using six native and six non-native plant species grown from seed in single- and multi-species experimental mesocosms. We examined the extent to which earthworms (1) influenced seedling survival, (2) selectively depredated native versus non-native plants, (3) impacted establishment based on seed size and/or root morphology, and (4) shaped community assembly. The effect of earthworms on seedling survival varied temporally and among species but inconsistently with respect to species origin. Differences in seed/seedling survival translated to changes in community assembly. Earthworms tended to reduce species abundance, richness, evenness, and diversity in multi-species mesocosms and led to the divergence of communities by treatment. In general, species with large seeds and fibrous roots dominated communities with earthworms present, whereas species with small seeds and taproots only persisted in multi-species mesocosms without earthworms. Our findings suggest that earthworms act as ecological filters in the early stages of invasion to shape community composition based on plant morphological traits. [ABSTRACT FROM AUTHOR]

Introduced earthworms alter the trajectory and composition of plant communities, for example, through their feeding, burrowing behaviour, and interactions with seeds. High densities of several earthworm species may decrease native biodiversity and disrupt restoration efforts in tallgrass prairies. This affects efforts to conserve and restore such habitat, which is of high conservation and restoration priority in eastern North America and typically restored through seeding events. To date, Lumbricus terrestris (Lumbricidae) and other species have remained largely undocumented in tallgrass prairies. We surveyed 22 tallgrass prairie sites in southern Ontario, Canada, to document earthworm density and species. Lumbricus terrestris was found at all sites. The average density was 66 ± 91 (SD) earthworms/m² across our sampling plots, mostly juveniles (~94%). The number of all earthworms per plot significantly increased with the number of earthworm middens in each plot (2 1 = 4.50, P = 0.034). Prairies with a large number of middens had high earthworm density, but middens alone appear to explain little variation in our data (linear mixed-effects model, marginal R² = 0.12) meaning there are other biologically important factors that affect their density. However, we found no effects of soil pH, organic matter content, or texture on the number earthworms per plot suggesting that earthworms can invade a range of tallgrass prairie soils with pH values between 5.27 and 7.67. [ABSTRACT FROM AUTHOR]

In no-till agroecosystems, presence of the earthworm Lumbricus terrestris L. can be a key driver in the replenishment of soil organic matter stocks post-harvest, through surface residue foraging and incorporation. The impact on such systems under different climatic conditions is, however, still unquantified. A field experiment was designed to determine incorporation of cereal harvest residues at three no-till agricultural sites in boreal conditions (SW Finland) focusing on L. terrestris impacts over the period from autumn harvest to spring sowing. Either spring barley, wheat or oats were cultivated at the sites. Following the harvests, representative masses of residues were applied on small experimental plots (0.25 m2) with cleaned soil surfaces in areas of inherently high (LT+: 10.6 ± 2.1 ind. 0.25 m-2) and low (LT-: 1.8 ± 0.7 ind. 0.25 m-2) L. terrestris density within the fields. Residues were covered with metal mesh caging and left until spring sowing, when changes in residue mass were recorded and plots sampled for earthworms. The reduction of straw residue mass varied between sites, from no difference between the LT+ and LT- treatments to 19 % and 59 % higher mass reduction in LT+. Amount of earthworm castings on the residues was also quantified and findings indicated a positive correlation with earthworm (also endogeic) density. For L. terrestris , earthworm species abundance relationships indicated competitive interaction with epigeics and positive interaction with endogeics. Results showed that L. terrestris foraging can enhance the incorporation of cereal surface residues outside of the boreal growing season and that earthworm surface casting also has a role in residue burial. However, the increase of incorporation by L. terrestris activity, interrupted by winter conditions, was moderate and did not lead to marked exposition of the soil surface by experimental end, even at those plots with the highest L. terrestris foraging. The incorporation rate estimates may have been unrepresentative due to the exceptionally late harvest during the study period. Investigations covering the whole year from multiple growing seasons are needed for a comprehensive assessment of earthworm impacts on crop surface residue dynamics. • Residue incorporation by L. terrestris studied outside the Boreal growing season. • Effects varied but incorporation rate up to 59 % higher when L. terrestris present. • Casting on residues by L. terrestris and other earthworms contribute to burial. • L. terrestris density had positive correlation with endogeics, negative with epigeics. • Free-residue approach presents an alternative in the study of earthworm foraging. [ABSTRACT FROM AUTHOR]

Abstract Biological invasions by cryptic ecosystem engineers can alter the ecological and socio‐economic values of ecosystems in ways that may take decades to detect. The invasion of North American glacial refuges by non‐native earthworms offers a prominent but understudied example of a cryptic invasion. Non‐native earthworms are known to alter carbon sequestration, disrupt mycorrhizal networks and homogenize plant communities, but natural resource managers still lack robust protocols to identify and safeguard high conservation value communities (HCVCs) from such invasions. In the absence of such protocols, or reliable methods to eradicate non‐native earthworm populations once established, there is an urgent need for methods to identify HCVCs at risk of or potentially shielded from earthworm invasion by the existence of abiotic barriers to their dispersal or persistence in such sites. We developed species distribution models (SDMs) using in situ field surveys and remotely sensed data to (1) identify factors limiting the occurrence of non‐native Lumbricus earthworms in imperilled coastal Douglas‐fir (Pseudotsuga menziesii) forest and Garry oak (Quercus garryana) and maritime meadow ecosystems endemic to glacial refugia of the Pacific Northwest of North America and to (2) evaluate their influence on plant species diversity and identify abiotic factors capable of preventing their dispersal or persistence at a site. As predicted, shallow, drier soils and steeper terrain limited earthworm occurrence and abundance in our highly heterogeneous study area, and earthworm presence appeared to reduce plant species richness. Our results indicated that HCVCs endemic to shallow‐soil (

Soil structure is closely linked to biological activities. However, identifying, describing and quantifying soil aggregates remain challenging. X‐ray micro computed tomography (X‐ray μCT) provides a detailed view of the physical structure at a spatial resolution of a few microns. It could be a useful tool to discriminate soil aggregates, their origin and their formation processes for a better comprehension of soil structure properties and genesis. Our study aims to (a) determine different X‐ray μCT‐based aggregate parameters for differentiating earthworm casts belowground (earthworm aggregates) from aggregates that are not formed by earthworms (non‐earthworm aggregates), and (b) to evaluate if these parameters can also serve as specific "tomographic signatures" for the studied earthworm species. For this purpose, we set up a microcosm experiment under controlled conditions during 8 weeks, including three species of earthworms tested separately: the epigeic Lumbricus rubellus, the anecic Lumbricus terrestris and the endogeic Allolobophora chlorotica. Our results show that X‐ray μCT analysis helps distinguish earthworm aggregates from non‐earthworm ones using (a) the relative volume of the components within aggregates and (b) the volumetric mass of aggregates and their global volume. In particular, the volume ratio of mineral grains within the aggregates is significantly different according to earthworm species. So, X‐ray μCT is a powerful and promising tool for studying the composition of earthworm casts and their formation. However, future research is needed to take into account the shapes and spatial distribution of the aggregates' components, in particular the different states of organic matter decomposition. Highlights: Can earthworm belowground casts be differentiated from other soil aggregates using X‐ray μCT?The use of X‐ray μCT for characterizing soil aggregates at a spatial resolution of a few microns.A combination of X‐ray μCT variables discriminates earthworm casts from non‐earthworm aggregates.X‐ray μCT, used alone, is relevant for defining species‐specific signatures of earthworm casts. [ABSTRACT FROM AUTHOR]

Background: Glyphosate-based herbicides (GBHs) are among the most often used pesticides. The hundreds of GBHs used worldwide consist of the active ingredient (AI) glyphosate in form of different salts, possibly other AIs, and various mostly undisclosed co-formulants. Pesticide risk assessments are commonly performed using single AIs or GBHs at standard soil conditions without vegetation. In a greenhouse experiment, we established a weed population with common amaranth (Amaranthus retroflexus) to examine the effects of three GBHs (Roundup LB Plus, Roundup PowerFlex, Touchdown Quattro) and their corresponding AIs (salts of glyphosate isopropylammonium, potassium, diammonium) on the activity and physiological biomarkers (glutathione S-transferase, GST; acetylcholine esterase, AChE) of an ecologically relevant earthworm species (Lumbricus terrestris). GBHs and AIs were applied at recommended doses; hand weeding served as control. Experiments were established with two soil types differing in organic matter content (SOM; 3.0% vs. 4.1%) and other properties. Results: Earthworm activity (casting and movement activity) decreased after application of glyphosate formulations or active ingredients compared to hand weeding. We found no consistent pattern that formulations had either higher or lower effects on earthworm activity than their active ingredients; rather, differences were substance-specific. Earthworm activity was little affected by soil organic matter levels. Biomarkers remained unaffected by weed control types; GST but not AChE was decreased under high SOM. Water infiltration after a simulated heavy rainfall was interactively affected by weed control types and SOM. Leachate amount was higher after application of formulations than active ingredients and was higher under low SOM. Glyphosate concentrations in soil and leachate were strongly affected by application of formulations or active ingredients and varied with SOM (significant weed control type x SOM interaction). Conclusions: We found that both commercial formulations and pure active ingredients can influence earthworms with consequences on important soil functions. Glyphosate products showed increased, reduced or similar effects than pure glyphosate on particular soil functions; soil properties can substantially alter this. Especially at lower SOM, heavy rainfalls could lead to more glyphosate leaching into water bodies. A full disclosure of co-formulants would be necessary to further decipher their specific contributions to these inconsistent effects. [ABSTRACT FROM AUTHOR]

Earthworms feed on organic matter present at the soil surface or within the soil. Thus, its distribution in the soil profile is likely to greatly influence earthworm behavior and, in turn, their burrow system. To test this idea, two anecic and two endogeic earthworm species were introduced into repacked soil cores (depth = 30 cm) upper half filled with a top soil containing 4% organic matter (0–15 cm) and lower half filled with a deep soil at 2% organic matter (15–30 cm). Earthworm behavior was studied using X-ray tomography combined with luminophores (colored particulate tracers of 63–125 μm size) placed at 0, 3, and 12 cm depth, a method widely used in sediment ecology. We observed that anecic and endogeic earthworms had contrasting reactions to the conditions with only endogeic species burrowing more intensively in the upper part. From a quantitative point of view, only a few percent of luminophores were displaced. However, luminophore displacements also provided qualitative information to complement the tomography: (i) endogeic species and especially Aporrectodea caliginosa bioturbated the most soil close to the surface (3 cm depth) and (ii) the two anecic species influenced the luminophore distribution differentially with Lumbricus terrestris displacing significantly more luminophores, whatever their initial depth, than Aporrectodea nocturna due to intense surface cast activity. Beyond methodological developments, our study found that endogeic earthworms burrow more in zones with higher organic matter contents and this explains why they are mainly found close to the soil surface in non-tilled soils. [ABSTRACT FROM AUTHOR]

A European badger (Meles meles Linnaeus, 1758) male was found killed on a road near the city of Český Krumlov (South Bohemian Region, Czechia) on May 12th, 2020. Investigation of its stomach content revealed the animal had been feeding on earthworms prior to its death. The earthworms were chewed up into pieces which were 7-49 mm long. Eleven specimens were identified as Lumbricus terrestris (Linnaeus, 1758) and one as Aporrectodea cf. caliginosa (Savigny, 1826). We surmise that the animal was hit by a car while picking up earthworms on the wet road after previous heavy rain. This hypothesis is supported also by the fact that the number of anterior and posterior earthworm body parts in the stomach was the same. It is well known that the earthworm's anterior parts are more common within stomach content, because when badgers pull the worms out of the soil, they will often tear them in two. We were unable to find any published information on badgers killed by traffic when exploiting food resources on the roads. We find this surprising because besides earthworms, badgers may take advantage of other road-kill. We propose that further studies on European badger road mortality should include investigation of the stomach content of dead animals. Moreover, any potential food resource located in the vicinity of a given traffic victim should be noted as well. [ABSTRACT FROM AUTHOR]

Soil-associated invertebrates which are coprophagic are capable of acting as paratenic hosts for Toxocara species larvae eggs. The aim of the present study was to assess the role of Lumbricus terrestris earthworms as potential intermediate host for Toxocara species. A total of 240 earthworms were collected from the public places in four areas of Karaj, Alborz Province, Iran. The subjects of the study were digested to detect Toxocara species using microscopy and molecular analyses. Toxocara larvae and larval eggs were recovered from 1.7% (4/240) of the sampled earthworms. The recovery rate in Shah'Abbasi and Talaghani regions in the studied areas was higher than that of the other regions. In the mentioned area, 8.3% (4/48) of earthworms were revealed to be positive for Toxocara species by microscopic observation and only one was confirmed to be positive for Toxocara canis by polymerase chain reaction (PCR). This is the first molecular report of Toxocara canis infective larvae in Lumbricus terrestris earthworms that could be demonstrated in common environment. [ABSTRACT FROM AUTHOR]

Earthworms are soil invertebrates that play an important environmental role and are often referred to as “ecosystem engineers”. These invertebrates can influence several organisms, from microscopic life forms to plants. Although many works had reported positive effects of earthworms on plant growth, studies combining these invertebrates and soil pathogens showed numerous positive interactions. Fusarium wilt is a global disease that can cause severe damage to strawberry fields. The aim of this study was to evaluate the effects of inoculation of earthworms (Lumbricus terrestris) and Fusarium wilt (Fusarium oxysporum f. sp. fragariae) in strawberry plants. This greenhouse experiment was carried out in the University of Seville School of Agricultural Engineering, Utrera City, Spain. Strawberries (Rooted cuttings) were planted in plastic pots and administered the following treatments: Control (absence of F. oxysporum f. sp. fragariae and earthworms), T1 (absence of F. oxysporum f. sp. fragariae, two L. terrestris per pot), T2 (inoculum of F. oxysporum f. sp. fragariae, absence of L. terrestris), and T3 (inoculum of F. oxysporum f. sp. fragariae and two L. terrestris). Weekly fruit production was measured for seven months. After this period the shoot fresh weight and the leaf nutrient content was measured. The results obtained showed no interaction between L. terrestris and F. oxysporum f. sp. fragariae on strawberry production. T1 treatment resulted in fruit production superior to other treatments, including the control. An absence of differences in dry shoot matter was observed with earthworm treatment, and small differences were found in the leaf nutrient content. The earthworm inoculation was unable to suppress the negative effects of Fusarium wilt in strawberry production. However, positive effects such as a reduction in the disease severity were found in the earthworm treated plants. In treatments without F. oxysporum f. sp. fragariae inoculation, the presence of earthworms increased plant productivity by 44.21 g per pot, compared with the control.

Previous works has shown that the heavy metal pollution is major in the region of Annaba (Northeast Algeria). The aim of this study was to assess the impact of anthropogenic activities on soil quality using Lumbricus terrestris as a bioindicator. Soil samples and earthworms were collected during the autumn and spring at two sites: Sidi Amar located near to several industrial factories, while El Tarf situated in a rural area far from any anthropogenic contamination. The activities of glutathione S-transferase (GST) and acetylcholinesterase (AChE), biomarkers of oxidative stress and neurotoxicity, respectively were measured in earthmorms. The concentrations of heavy metals (Pb, Zn, Mn, and Fe) in soils and earthworm tissues were analyzed using atomic absorption spectrophotometry. The GST and AChE activities and the heavy metal concentrations were found to vary between sites and by season. Marked biomarker responses are noticed during the automn at the site closest to potential sources of pollution. These bioindicative stress response correlated with increasing metal concentration detected in soil and tissue samples. Thus, the difference recorded between the two sites is linked to their level of pollution. while the effect of seasons may be due to rains which promote leaching of heavy metals in soils. L. terrestris could serve as an useful biological indicator of soil contamination. [ABSTRACT FROM AUTHOR]

Biochar is the degradation-resistant product generated by the pyrolysis of organic materials and is produced for the intended use of land application in order to promote carbon sequestration and soil improvement. However, despite the many potential benefits biochar application offers, it is important to quantify any ecological impacts that may result from soil amendment in order to avoid potentially causing negative effects upon soil biota which are crucial in the many ecosystem services provided by soil. Any impacts on earthworms in particular are important to evaluate because of their pivotal role in organic matter breakdown, nutrient cycling and soil formation. In this study, we conducted a series of ecotoxicological assays to determine lethal and sublethal (avoidance, mass change and moisture content) effects of heavy biochar applications that reflect levels that may be used in soil restoration efforts. Two earthworm species, Eisenia fetida, an epigeic species, and Lumbricus terrestris, an anecic species, were utilised as test organisms. Two types of biochar, produced from wheat straw and rice husk feedstocks, respectively, were applied to OECD artificial soil and to a natural soil (Kettering loam) at rates of up to 20% w/w. The influence of biochar application on soil porewater chloride, fluoride and phosphate concentrations was also assessed. The biochar applications induced only a subtle level of avoidance behaviour while effects on survival over a 4-week exposure period were inconsistent. However, death and physical damage to some individual earthworms at high biochar application rates were observed, the mechanisms and processes leading to which should be investigated further. Earthworm development (mean mass change over time) proved to be a more sensitive measure, revealing negative effects on L. terrestris at 10% and 20% (w/w) wheat biochar applications in OECD soil and at 20% (w/w) applications of both biochars in Kettering loam. The moisture content of E. fetida remained remarkably consistent across all treatments (~ 82%), indicating that this is not a sensitive measure of effects. The high rates of biochar application resulted in increased chloride (2 to 3-fold) and phosphate (100-fold) concentrations in simulated soil porewaters, which has important implications for soil fertility and production but also for environmental management. [ABSTRACT FROM AUTHOR]

The role of below-ground interactions between microbial biocontrol agents and soil fauna for combatting soil-borne plant diseases have not been studied sufficiently. This study tested the hypothesis that the beneficial bacterium Bacillus velezensis UCMB5113 and the anecic earthworm Lumbricus terrestris positively influence health and growth of peas (Pisum sativum L.) infested with the pathogen Aphanomyces euteiches causing root-rot disease. A greenhouse fully factorial experiment studied the effects of A. euteches, B. velezensis and L. terrestris on the emergence, growth and health of pea plants. The factors B. velezensis and L. terrestris resulted in taller plants (p =.003 and p =.030). B. velezensis treatment resulted in a higher biomass of shoots and roots (p ≤.001 and p =.005). The effects increased with the presence of both factors (p =.036). Earthworms reduced the disease symptoms significantly (p =.032). The decreased disease symptoms caused by the earthworms might be due to the consumption of A. euteiches (direct effect) as well as soil disturbance (indirect effect). Interactions between the microorganisms added and the earthworms were shown. B. velezensis and L. terrestris can be useful for enhancement of plant growth and for biological control of root-rot in peas. [ABSTRACT FROM AUTHOR]

We carried out mesocosm experiments using either the anecic earthworm Lumbricus terrestris or the endogeic earthworm Allolobophora chlorotica and loam, silt loam and sandy loam soils to investigate the differing impact of these earthworm of different ecotypes on aggregate formation (percentage water stable aggregates, %WSA) and soil water holding capacity (WHC), two soil properties that underpin many of the ecosystem services provided by soils. Earthworms significantly increased %WSA (by 16–56% and 19–63% relative to earthworm-free controls for L. terrestris and A. chlorotica, respectively). For L. terrestris, this increase was significantly greater in the upper 6.5 cm of the soil where their casts were more obviously present. Allobophora chlorotica treatments significantly increased WHC by 7–16%. L. terrestris only caused a significant increase in WHC (of 11%) in the upper 6.5 cm of the sandy loam soil. Linear regression indicated a consistent relationship between increases in %WSA and WHC for both earthworm species. However, for a given %WSA, WHC was higher for A. chlorotica than L. terrestris likely due to the known differences in their burrow structure. Overall, earthworms increased soil %WSA and WHC but the significant species/ecotype differences need to be considered in discussions of the beneficial impacts of earthworms to soil properties. [ABSTRACT FROM AUTHOR]

The effects of microplastic exposure in aquatic organisms have been widely reported. Nonetheless, there is limited evidence of the effects of exposure in soil systems. Thus, the objective of this study was to evaluate the effects of microplastic exposure using as a bioindicator the species Lumbricus terrestris, exposed to different concentrations of microplastic (2.5%; 5%, and 7% w/w). Avoidance bioassays were carried out for 48 h in soil with and without microplastic; the gastrointestinal tract—crop/gizzard, foregut, and midgut—was dissected and acetylcholinesterase (AChE) was used as a biomarker of neurotoxicity stress. In parallel, bioassays of microplastic ingestion were carried out, and after 48 h of initiating the ingestion assay, using a stereo and fluorescence microscope, the microplastic distribution was observed in the different earthworm segments. The results obtained in the avoidance assay indicated a lack of preference for either soil type; however, upon moving, the earthworms lost surface mucus, resulting in burns and lesions on their bodies, which were reflected in the increase in AChE enzyme levels, which was not directly related to microplastic ingestion, but rather likely acts as an external physical stress agent. The results of the ingestion bioassay showed that microplastic was present in all the earthworm segments, with a higher number of particles in the hindgut. The Lumbricus terrestris did not distinguish microplastics from soil particles, and given the high exposure concentrations, microplastics produced physical lesions on the mucus membranes of earthworms. Lumbricus terrestris showed to be a suitable bioindicator for testing the exposure to microplastic contamination in soil. [ABSTRACT FROM AUTHOR]

The invasive European earthworm, Lumbricus terrestris, is now widely distributed in North America. This success may result from high genetic diversity derived from multiple introductions from founder sources across Europe. Using a mitochondrial gene (COI) and microsatellite markers, L. terrestris from seven sites in the Champlain Valley of Vermont USA were scored for genetic diversity and population structure. This region has been a trading crossroads for centuries, thus likely to have received earthworms from multiple origins. COI sequences matched those reported for L. terrestris from Scotland, France, Austria, Denmark, Sweden, and Norway, and 2–5 haplotypes were found at each site. Genetic diversity (microsatellites) was great for each site, but not notably greater than for earthworm populations in general, possibly because there may be allele size homoplasy, or some restriction in the number of alleles possible at any locus. The earthworms were genetically differentiated among the Vermont study sites, even those 0.6–13 km distant. These results support the view that L. terrestris is a successful invasive earthworm because multiple introductions provided ample genetic variation for natural selection and local differentiation among locations in North America. Last, a large number of microsatellite markers is provided, including suggested PCR programs, for free use by future researchers. [ABSTRACT FROM AUTHOR]

The olive-oil industry generates large amounts of residues that, in the past, were accumulated in evaporating ponds in many Mediterranean countries. Currently, these open-air ponds pose a serious environmental hazard because of toxic chemicals that concentrate in their sediments. Bioremediation of olive mill waste (OMW) sediments has emerged as a viable option for managing this environmentally problematic residue. Here, we postulate that inoculation of an OMW-soil mixture with earthworms may be a complementary bioremediation strategy to that using native microorganisms only. A laboratory study assessed the ecotoxicity of OMW-amended soils (10%, 20%, 40% and 80% w/w) combining earthworm biomarker responses and soil enzyme activities. The doses of 40% and 80% were toxic to earthworms, as evidenced by the high mortality rate, loss of body weight and signs of oxidative stress after 30 d of soil incubation. Conversely, doses ≤ 20% w/w were compatible with earthworm activity, as indicated by the significant increase of soil enzyme activities. Total concentrations of phenolic compounds decreased by more than 70% respect to initial concentrations in 10% and 20% OMW treatments. These results suggest that OMW sediments intentionally mixed with soils in an up to 20% proportion is a workable bioremediation strategy, where earthworms can be inoculated to facilitate the OMW degradation. [ABSTRACT FROM AUTHOR]

Earth has a natural magnetic field that many animals use for orientation and navigation. With the development of technology, these natural systems have been exposed to high levels of man-made electromagnetism from the heavy usage of electric devices. This study aims to understand the possible effects of artificial magnetic fields on the behavioral responses of the earthworm, which is used in this study as a model organism in laboratory conditions. The 3 experimental groups, each composed of 20 earthworms, were exposed to 190-520 µT magnetic fields using a 1.5 V current for 1-h durations in a wire-wrapped vivarium. The experimental and control groups were kept in similar conditions. A camera recorded the positions of the earthworms every 5 min. The angles, in terms of the mean vector of each earthworm's position beginning in the center of the vivarium, were documented using the Adobe Photoshop CS6 program. The mean vectors and angles of different experimental designs and controls were compared using circular statistics. The orientations of the earthworms in the control (261.4° ± 101.6°) and experimental (251.2° ± 94.1°) groups were statistically different (P < 0.005), and a deviation of approximately 10° to the east was observed for the experimental group in comparison to the control group. [ABSTRACT FROM AUTHOR]

Microorganisms from L. terrestris gut previously exposed to different types of plastic (PET, LDPE, LLDPE, and PS) were studied to be used as probiotics of earthworms in plastic-contaminated soils (LDPE, LLDPE and recycled mulching film) at mesocosm-scale trials. The most abundant morphotypes with enzymatic capacities of interest were identified. Pseudomonas alkylphenolica (PL4) and Pseudomonas putida (PL5) strains were selected to be used as inoculants using Morus alba leaves as carriers to strengthen the intestinal microbiota of earthworms. Culture (selective cetrimide agar medium) and molecular (qPCR) techniques were used to trace the presence of the inoculum in the intestine of the earthworms. Additionally, a metataxonomic analysis was carried out to study the biodiversity and functionality of the earthworm microbiome, and their measure of survival and weight. Probiotics improved the survival rates of earthworms exposed to plastics, which also increased the abundance of microbial groups of interest in plastic bioremediation tasks. [Display omitted] • Exposure of earthworms to plastics for enrichment of the specialized microbiota. • Cultivar and molecular techniques for tracking probiotics in the gut microbiome. • Probiotics increased the abundance of functional microbiota in L. terrestris. • Plastics and probiotics modify microbial structure of L. terrestris gut. • Selected probiotics boosted plastic-exposed L. terrestris survival rate. [ABSTRACT FROM AUTHOR]

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Microplastic (MP) pollution constitutes an emerging type of pollution threatening both aquatic and terrestrial ecosystems. The impact on aquatic ecosystems has been extensively studied, but the effect on terrestrial ecosystems and their inhabitants is mostly underexplored. In this study, we explored the effect of MP pollution on gut bacterial microbiome of endogeic (Aporrectodea caliginosa) and anecic (Lumbricus terrestris) earthworms. The experiments were performed in sandy soil with 0.2% of low-density polyethylene MPs (LDPE MPs). We observed that the endogeic earthworms had 100% survival, while anecic earthworms survived 25 days in the control (i.e. in absence of MPs) and 21 days in the treatment with LDPE MPs. The main driver of shifts in the diversity and composition of the bacterial communities in the gut of tested earthworms was the lifestyle of the worms, followed by the presence of MPs. The bacterial microbiome diversity was significantly different among the two types of earthworms, and the highest bacterial diversity was found in the gut of the endogeic earthworms. The effect of MPs on gut bacterial microbiome was clearly observed in the changes in the relative abundance of several phyla and families of the bacterial communities in both types of earthworms, although it was most evident in the anecic earthworms. The Actinobacteriota, Proteobacteria, and Firmicutes were the main groups enhanced in the MP treatments, suggesting enrichment of the bacterial communities with potential plastic degraders., (© The Author(s) 2024. Published by Oxford University Press on behalf of FEMS.)

Abstract Herein, we examined whether synergistic effects of earthworms (Lumbricus terrestris) and pine needle-derived biochar result in biochar-coated burrows with enhanced carboxylesterase (CE) activity (a pesticide-detoxifying enzyme). Biochar was placed at the top of soil columns at two doses (2.5 and 5% w/w dry mass), with an additional biochar-free treatment as control. Carboxylesterase and dehydrogenase activities were measured in the burrow walls sampled at three depths (0–4, 8–12, and 18–22 cm). Biochar was recovered from these samples to confirm its vertical transport and enzymatic activation. We tested whether biochar protected CE activity against desiccation stress of burrow wall samples. Likewise, the role of earthworm mucus in stabilizing CE onto biochar surface was also investigated by measuring the enzyme activity in fresh biochar particles previously incubated in the presence of earthworm mucus and purified esterase. Finally, we checked for the sensitivity of biochar-bound CE activity against selected organophosphorus pesticides. The main results were: i) co-application of earthworms and biochar caused a significant increase of CE activity in the first 12 cm of the soil column, ii) recovered biochar particles displayed CE activity which was significantly higher in the particles collected from the bottom of columns, iii) soil desiccation decreased the enzymatic activity, although such effect depended on biochar treatment and column depth (22–77% inhibition). Nevertheless, CE activity still was higher in the samples from the 5%-biochar treatment than activity in control and 2.5%-biochar treatments, iv) earthworm mucus favored the retention of CE onto the biochar surface, and v) the activity of biochar-bound CE was sensitive to inhibition by chlorpyrifos-oxon. These results suggest that the joint application of L. terrestris and biochar may be a suitable vermiremediation strategy to inactivate OP pesticides. Graphical abstract Unlabelled Image Highlights • Synergistic effects of earthworms and biochar increased carboxylesterase activity. • Biochar particles displayed higher esterase activity in burrow bottom than in the surface. • Earthworm mucus facilitated adsorption of carboxylesterase to biochar surface. • Biochar-bound carboxylesterase inactivated organophosphorus pesticides. [ABSTRACT FROM AUTHOR]

Rotenone (ROT) was shown to affect cerebral ganglions (CGs) of Lumbricus terrestris as a pioneering observation in our earlier investigation. Though ROT is a well-known neurotoxin causing neurodegeneration (ND), the precipitation of movement dysfunction remains largely unknown. We have designed the current study to analyze motor abnormalities in worms by exposing them to different concentrations (0.0–0.4 ppm) of ROT for 7 days. GABA, cholinergic receptor, serotonin transporter (SERT), acetylcholine esterase (AchE), and dopamine–β-hydroxylase that are well known for their involvement in neuromuscular junctions were investigated by qRT-PCR. Further, neuronal mitochondrial genes (cytochrome C oxidase-2, NADH deydrogenase-1, cytochrome-b) and actin-1 that are essential for regeneration and calreticulin (phagocytosis) were investigated. The levels of neurotransmitters, lipids, ATPase, neuronal behavior analyses, and fluorescence analysis (lipid droplets) were performed in CGs which showed significant variations at 0.3 ppm. Ultrastructural changes in lipid droplet and neuromelatonin were prominent in 0.3 ppm. Dose-dependent effect of ROT on behavior alteration and expression of m-RNAs studied suggested that at 0.3 ppm, it could deteriorate motor and cognitive functions. We predict that perhaps, by virtue of its effect on cerebral ganglionic genes and their neurotransmitting potential, ROT may cause morbidities that resemble features characteristic of hemiparkinsonic degeneration. [ABSTRACT FROM AUTHOR]

Abstract Preservation of the soil resources stability is of high importance for ecosystems, particularly in the current era of environmental change, which presents a severe pollution burden (e.g. by heavy metals) to soil fauna. Gut microbiomes are becoming recognized as important players in organism health, with comprehension of their perturbations in the polluted environment offering new insights into the nature and extent of heavy metal effects on the health of soil biota. Our aim was to investigate the effect of environmentally relevant heavy metal concentrations of cadmium (Cd) on the earthworm (Lumbricus terrestris) gut microbiota. Our results revealed that Cd exposure led to perturbations of earthworm gut microbiota with an increase in bacteria previously described as heavy metal resistant or able to bind heavy metals, revealing the potential of the earthworm-gut microbiota system in overcoming human-caused heavy metal pollution. Furthermore, an 'indicator species analysis' linked the bacterial genera Paenibacillus , Flavobacterium and Pseudomonas , with Cd treatment, suggesting these bacterial taxa as biomarkers of exposure in earthworms inhabiting Cd-stressed soils. The results of this study help to understand the impact of anthropogenic disturbance on soil fauna health and will have implications for environmental monitoring and protection of soil resources. Highlights • Environmentally relevant concentrations of Cd alter earthworm gut microbiota. • Heavy metal resistant bacterial taxa increased in the gut as a result of Cd intake. • Several bacterial indicators were defined as potential biomarkers of exposure to Cd. • Many indicators belong to genera Paenibacillus , Flavobacterium and Pseudomonas. [ABSTRACT FROM AUTHOR]

Abstract Earthworms play an important role in soil organic matter (SOM) dynamics and soil structure formation, including soil porosity and aggregate stability. Earthworms feed on organic inputs such as crop residues (CR) which are displaced by mouldboard ploughing. In a 61-day mesocosm experiment, we investigated the effects of CR placement (surface-applied vs. incorporated) and different earthworm species (combinations) on: 1) the survival and biomass of the earthworm species Lumbricus terrestris , L. rubellus , and Aporrectodea caliginosa , representing anecic, epigeic and endogeic ecological groups, respectively; and 2) earthworm-mediated soil structure formation. Earthworms were present either as single species or as species mixtures combining anecics with each of the other groups. Incorporating CR reduced biomass of surface-feeders (L. terrestris : −30% of initial body weight vs. −9% when CR were surface-applied; L. rubellus : −74% vs. −24%, respectively). L. rubellus survival was also lower when CR were incorporated (50%) than when CR were surface-applied (92%). In surface-applied CR treatments, the amount of particulate organic matter (POM) > 250 μm in the soil profile was positively affected by L. terrestris in the soil upper 20 cm by 16.5%. A similar but weaker effect was found when CR were incorporated (9% increase). Large water-stable macroaggregates (>2000 μm) increased in the upper 20 cm soil only when CR were surface-applied and L. terrestris was present (from 2.7 to 13.1 g kg−1). Small water-stable aggregates increased with functional groups interactions at all soil depths, irrespective of the CR placement. Surface-applied CR increased soil porosity at 2.5–10 cm depth. Large water-stable macroaggregate formation by earthworms was hampered through the incorporation of CR, although CR incorporation increased porosity between 2.5 and 30 cm soil depth despite reduced earthworm biomass. Furthermore, small macroaggregate formation was hampered by single species, whereas combining functional groups stimulated their formation. Under field conditions residue incorporation might result in trade-offs between the contribution of surface-feeding earthworms to soil porosity and i) their fitness, as surface-feeding earthworms' body weight loss was larger than when crop residues were surface-applied; as well as ii) large water-stable macroaggregates formation, as no increase in those was found when CR was incorporated. Highlights • Incorporation of crop residues reduced biomass of surface-feeding earthworms. • Large water-stable aggregates increased only when residues were surface-applied. • Soil porosity increased at depth with residues incorporated. • L. terrestris affected SOM distribution only when residues were surface-applied. • Earthworm ecological group combinations increased water-stable macroaggregates. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Enhanced total antioxidant capacity in earthworms incubated in biochar-amended soils. • Long-term exposure to biochar increased the earthworm digestive enzyme activities. • The IBRv2 index was a suitable tool for assessing harmful effects of biochar. • The joint application of biochar and earthworms increased soil enzyme activities. Abstract Potential harmful effects of spent coffee grounds (SCGs)-derived biochar on earthworms (Lumbricus terrestris) were investigated through two complementary experiments, which assessed the avoidance response of earthworms to biochar-amended soils (experiment 1), and the response of oxidative stress biomarkers and digestive enzymes (experiment 2). The main results were: 1) the highest dose of biochar (5% w/w) caused a significant avoidance response of earthworms (75% individuals avoided these treated soils after 48 h); 2) signs of oxidative stress were early detected in earthworms exposed to biochar (1 and 5% w/w) as indicated by the integrated biological response index; 3) earthworms exposed to biochar-amended soils for 30 d experienced a significant increase of digestive enzyme activities measured in both the gastrointestinal tissue and the luminal content; 4) interaction between earthworms and biochar led to a higher soil extracellular enzyme activities in the 1% biochar treatment than that of control and 5% biochar treatments. These findings suggest that the joint application of SCG-biochar and L. terrestris is a workable approach for improving soil quality in terms of soil biochemical promotion, although earthworms may develop some physiological mechanisms of biochar tolerance (antioxidant defenses). [ABSTRACT FROM AUTHOR]