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This study aims to assess the impact of two pesticides commonly used in Algeria (Prosaro XRT and Decis 25 EC), as well as their combinations at recommended doses, on a non-target species bioindicator of soil pollution, the earthworm Aporrectodea caliginosa, using physiological (mortality and growth) and biochemical parameters (proteins, glutathione, catalase activity and glutathione S-transferase, acetylcholine esterase, lipoxygenase). The recommended dose and its double were tested individually and in combination for this. It should be noted that the protocol used and the initial concentrations selected are the same as those used in the field. After 7 and 14 days (7D/14D) of exposure, all dosages were administered. Our findings show that the pesticides tested had no effect on earthworm survival. However, a significant decrease in their growth rates depending on the different concentrations was observed for the different treatments over the entire exposure period of 7 or 14 D. The greatest reductions (31.62%, 35.04%) are reported after 14D for the high concentrations of Decis alone (D2) as well as for the combined treatment Prosaro/Decis (P2/D2). At the same time, an increase in total protein contents (more than 50% after 14D) as well as a decrease in acetylcholine esterase activity were reported for all treatments. We were also able to identify the induction of oxidative stress after xenobiotic exposure, which is more pronounced at the end of the treatment (14D), resulting in the stimulation of the antioxidant system (gluthione, glutathione S-transférase, catalase) as well as the induction of lipoxygenase, which is responsible for the oxidation of polyunsaturated fatty acids as well as the generation of reactive oxygen species (ROS) involved in the inflammatory phenomenon. Finally, it turns out that the species Aporrectodea caliginosa is sensitive to the different concentrations applied, even those used in the open field, and that Decis (deltamethrin) seems to be more toxic than Prosaro and that the combinaison P2/D2 is as toxic as Decis alone (D2). [ABSTRACT FROM AUTHOR]

Earthworms have great environmental importance; they occupy a great place among other soil invertebrates. Further, it contributes greatly to soil fertility and is a main component of the soil fauna. Various chemical pesticides are used that have multiple effects on plants in the soil ecosystem. Earthworms represent a strong bioindicator for the environmental toxicity analysis of soil pollution caused by pesticides. Chlorpyrifos is used in more than 100 countries and is applied annually to approximately more than a million acres of crops. The most beneficial crops include cotton, almonds, corn, fruit trees, oranges, bananas, and apples. In the present work, it was noticed that groups exposed to chlorpyrifos, an organophosphate pesticide, at doses of 0.05, 0.1, and 0.2 μg /cm² when compared with normal earthworms, it significantly affects the behavior of the worms, as it causes many distortions in the external appearance and also affects the stages of the earthworm life cycle, which lead to cocoon, juvenile, and adult death. When examining the histological sections, much damage to the tissues was observed. Even the pesticide led to much mortality among earthworms. [ABSTRACT FROM AUTHOR]

Silver nanoparticles (AgNPs) are increasingly used in consumer products and subsequently arrive in wastewater systems, accumulating as silver sulphide (Ag2S) in the resulting biosolids, which are commonly spread onto agricultural fields as a fertiliser. Experiments were performed to investigate the effect of AgNPs, using the endogeic earthworm Aporrectodea caliginosa as a test organism. In an acute toxicity experiment, A. caliginosa were exposed to soil containing different concentrations of AgNPs (0, 1, 5, 10, 50, 100, 250, 500, 750, and 1000 mg kg−1 dry soil) and Ag2S (0, 10, 50, 100, 500, and 1000 mg kg−1 dry soil). Earthworm biomass and mortality were monitored. Earthworms exposed to 500, 750 and 1000 mg kg−1 fresh AgNPs had mortality rates of 20%, 60% and 70%, respectively. Changes in biomass were directly related to AgNP concentration. Exposure to Ag2S did not affect biomass or mortality. Further experiments used 0, 10, 50, 100 and 250 mg kg−1 AgNPs and 0, 50, 100, 500, and 1000 mg kg−1 Ag2S to evaluate sublethal effects on A. caliginosa. Avoidance behaviour in a linear gradient was evaluated after 14 days. Earthworms significantly preferred soil that was free of either AgNPs or Ag2S. The same concentrations were used to assess effects on cocoon production of A. caliginosa exposed to AgNPs and Ag2S. In the first 3 months of AgNP exposure, higher concentrations had a negative effect on cocoon production, but this effect diminished thereafter. Ag2S had no discernible effect on reproduction. Overall, introduction of AgNPs into the soil through the application of biosolids appears to be of low concern to the tested endogeic earthworm. Highlights: High concentrations of AgNPs are toxic towards A. caliginosa. Earthworm mass affects susceptibility towards AgNP-toxicity. Aporrectodea caliginosa avoids low concentrations of AgNPs. Silver sulphide is less toxic to A. caliginosa than AgNPs. [ABSTRACT FROM AUTHOR]

Earthworm invasions often reduce biodiversity and affect the ability of ecosystems to perform ecosystem functions. Over the past few decades, European lumbricid species have spread widely in natural habitats in Western Siberia, without completely displacing the native species. The aim of the present experiment is to study the survival, reproductive potential, vertical distribution, abundance, and biomass of Aporrectodea caliginosa and Lumbricus rubellus invasive species for the region and the native species Eisenia nordenskioldi and their influence on each other. For this purpose, winter and vegetation experiments were conducted in mesocosms simulating the real situation of invasions in the same communities on the same types of soils with the same amount and composition of litter. The authors found that the native species was significantly inferior to A. caliginosa in reproduction rate, number of offspring, and final biomass, but had an advantage over L. rubellus. The native species was positively influenced by the presence of A. caliginosa. In the experiment, there was a significant rejuvenation of the populations of the studied species, as well as an increase in abundance and relative mass under interaction conditions compared to mono variants. The native species had advantages over the invasive species in terms of winter survival. The natural volume of litter used in the experiment was insufficient for L. rubellus. According to the results of the experiment, it can be assumed that the spread of L. rubellus will continue to be limited to non-freezing biotopes rich in organic matter. A. caliginosa will spread in natural communities and agrocenoses of Western Siberia. [ABSTRACT FROM AUTHOR]

Aporrectodea caliginosa (Savigny, 1826) is an earthworm species ubiquitously inhabiting a wide range of agricultural soils across temperate climate environments. Through its trophic activities, it shapes the microbial structure of the drillosphere within the rhizosphere, which may have a pronounced impact on processes occurring in the soil governed by microorganisms. This study aims to test a hypothesis that A. caliginosa guts serve as soil bioreactors where the processes of emergence of new bacterial and fungal taxa occur. Furthermore, we have found that this earthworm species is an accelerator of the growth of endophytic bacteria across the rhizosphere. We assessed microbes that are promoted and those that are partially or totally exterminated by this species using metagenomics. Additionally, new ecological indicators were proposed as single-value tools for assessing the effect of changing the biodiversity of the soil microbiome caused by the earthworms. Collectively, our results showed that (i) A. caliginosa caused a 37.80 % reduction of fungal DNA amplicon read abundance (mainly Basidiomycota, Rozellomycota, Monoblepharomycota, Mucoromycota, Ascomycota, and unidentified fungi) in casts in comparison to the abundance in the soil samples; inversely, the relative DNA read abundance of bacteria (mainly Bacteroidota, Proteobacteria, Actinobacteria, and Verrucomicrobia) were enhanced by 16.75 % after the gut transit. The mutualistic endosymbionts of A. caliginosa accounted for 10.76 % relative DNA read abundance, most of which were assigned to cereal endophytes (6.76 % relative DNA read abundance). Further studies are needed to confirm the tendencies in shaping microbial structure of the casts donated by this earthworm and their influence on cereal endophytes population in soil. • Aporrectodea caliginosa earthworm can serve as a soil manager of agroecosystem. • caliginosa cause a reduction of fungi abundance by 37.80 % and enhancement of bacteria abundance by 16.75 % in casts. • The trophic activity of the earthworm increases the reservoir of plant endophytes. • Action of the earthworm in soil resulted that 11.66 % of all bacteria was emerged. • New ecological indicators measuring the impact of earthworms on soil microbial biodiversity were proposed. [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]

In this paper a batch of earthworms from Afghanistan was studied and previous reports on the earthworm fauna of the country were evaluated. In the present study, earthworms were collected by digging and hand sorting, and fixed in 80% ethanol. Six species belonging to three families were identified. They are Aporrectodea caliginosa, Ap. rosea, Eiseniella tetraedra, Drawida annandalei, Amynthas corticis, and Metaphire bahli. Among them A. corticis, Ap. caliginosa, D. annandalei, and M. bahli are new records for the country. Nine species have previously been reported from Afghanistan of which two were collected in the current survey as well. Therefore, this study in Afghanistan increased the number of earthworm species registered for the country from 9 to 13 belonging to nine genera and three families. Out of the 13 species, 10 (Ap. caliginosa, Ap. jassyensis, Ap. trapezoides, Ap. rosea, Bimastus parvus, Dendrobaena byblica, D. fedtschenkoi, Eisenia fetida, Eis. tetraedra, and Lumbricus rubellus) belong to the Holarctic family Lumbricidae, two species (M. bahli and A. corticis) to the family Megascolecidae, and one species (D. annandalei) to Moniligastridae. Most of the species (10) are peregrine and only three of the lumbricid species in Afghanistan are regarded as autochthonous, viz., Ap. jassyensis, D. byblica, and D. fedtschenkoi. The diversity and distribution of earthworms in Afghanistan is far from complete. To fill this gap in our knowledge on the earthworm fauna of the studied region more detailed investigations are needed to explore the earthworm fauna of this vast country.

Numerous studies have confirmed the damage caused by excessive exposure to ultraviolet-A rays. Malignant melanoma and skin cancer are two of the most serious health consequences. Thus, the UV-A protectant is intended to protect the skin, especially the two primary layers of skin (epidermis that represents the interface between the body and its surroundings and dermis). Spider silk is the most powerful natural fibre due to its regeneration, biocompatibility, antimicrobial, wound healing, antiseptic, and blood clotting properties. This work targeted to determine the protective effect of spidroin extract against UV-A radiation damage. Earthworms Aporrectodea caliginosa were collected from Assiut University's farm. Each set of ten earthworms was separated into six groups and placed in a plastic container. Webs of spiders collected from trees and old houses. Spidroin was extracted and utilised in this work to determine the potential effects of topical application on UV-A protection. The experiment is divided into two sections: (1) UV-A exposure and (2) the use of spidroin extract to protect the earthworms from ultraviolet radiation. Two control groups (1،2) of worms were not received UV-A exposure, and four groups (3,4,5,6) were exposed to UVR-A. In contrast, groups (5,6) were received spidroin extract before exposure to UV-A. Each group from the groups (3,4,5,6) was exposed for three consecutive days (¼ hour/day, ½ hour/day, and 1 h/day), using a UV-Lamp with a wavelength of 366 nm. The histopathological changes revealed that after 1⁄4 h of UV exposure, the cuticle was swollen with a slightly detached epithelium. The cuticle was down after 1⁄2 h of exposure, and the epidermis was totally damaged and necrosed. After 1 h, the exposure showed destruction of the epidermis in the circular muscle with a loss of muscle filament integrity, varying size, and altered nucleus form, along with mild disintegration of longitudinal muscle. Spidroin extract is critical for earthworm protection against UV-A radiation damage and able to regeneration. For the first time, morphological and histological analysis was established to detect the Spidroin extract evaluated for topical application on earthworms. Earthworms can be considered as a robust human skin model prior to UV-A exposure. It induces a complete protective effect against UV-A radiation damage in earthworms. [ABSTRACT FROM AUTHOR]

The availability of conventional linear mineral phosphorus (P) fertilization will become lower as phosphate rock stocks are limited and strongly concentrated in a few locations. Therefore, we need to increase agronomic P use efficiency and find alternative, recycled, sources of P. Two possible solutions mentioned in the literature are (i) using struvite, a mineral circular P fertilizer; and (ii) making use of earthworm activity, which has been shown to increase P availability. Here, we study the interaction between these two approaches, with the hypothesis that earthworms could increase the P availability from the poorly soluble struvite. We set up a field-based mesocosm experiment in a sandy soil with a low agronomic P status with 13 different treatments combining three earthworms species (Lumbricus rubellus Hoffmeister, Aporrectodea caliginosa Savigny and A. longa Ude alone or in a threes species mixture), different P fertilizers (no P, Triple Super Phosphate (TSP) and struvite). The experiment lasted 13 months (five fertilisation-harvest cycles). We found that, in field conditions, the yield and P uptake of Lolium perenne did not differ between fertilization with struvite or TSP. Earthworms only played a minor role in explaining ryegrass P uptake compared to fertilisation. We did not see either positive nor negative interactions between earthworms and struvite, meaning that earthworms did not further increase the P availability from struvite. The equal performances of struvite and TSP are explained by an enhanced effort from plants to actively take up P through a modification of root traits. This includes increased arbuscular mycorrhizal fungi colonisation and the production of finer and longer roots. Our results show that struvite performs comparably to TSP under realistic field conditions, making it a viable alternative to phosphate rock-based fertilizers. • Struvite is just as effective as triple superphosphate under field conditions. • Earthworms do not further increase the effectiveness of struvite-P. • Struvite leads to a slight P limitation, triggering root P acquisition strategies. • Struvite increases arbuscular mycorrhizal fungi colonisation. [ABSTRACT FROM AUTHOR]

Permanent grasslands provide a healthy and undisturbed environment. We investigated how mulching altered the soil physicochemical parameters, earthworm abundance, biomass, species composition and vegetation cover compared to grassland and cultivated alfalfa field. Microplots (2 × 2 m) were mulched with either weed control fabric (WF) alone or WF combined with straw (WF + S) on a grassland to grow tomato in Ősagárd (Nógrád county, Hungary) between 2018 and 2021. We had two other microhabitats: a conventionally cultivated alfalfa field (CA) and grassland (GR). We measured soil parameters (physical: soil moisture content (SMC), soil penetration resistance (SPR); chemical: pH, soil organic matter; and biological: earthworm abundance, biomass, species composition and vegetation). SMC was significantly higher on covered plots (WF; WF + S) compared to CA and GR. SPR values were the highest in CA and GR at 20 cm depth. The abundance and biomass of earthworms were the highest in GR and lowest in CA in all seasons. Plant abundance was highly influenced by season and habitat. Despite the higher compaction and lower SMC figures, grass vegetation still provided a more suitable environment for earthworms than mulched plots (WF, WF + S). Therefore, where there is agricultural production on grassland, we suggest leaving uncultivated and uncovered patches as biodiversity corridors. [ABSTRACT FROM AUTHOR]

In this paper a batch of earthworms from Afghanistan was studied and previous reports on the earthworm fauna of the country were evaluated. In the present study, earthworms were collected by digging and hand sorting, and fixed in 80% ethanol. Six species belonging to three families were identified. They are Aporrectodea caliginosa, Ap. rosea, Eiseniella tetraedra, Drawida annandalei, Amynthas corticis, and Metaphire bahli. Among them A. corticis, Ap. caliginosa, D. annandalei, and M. bahli are new records for the country. Nine species have previously been reported from Afghanistan of which two were collected in the current survey as well. Therefore, this study in Afghanistan increased the number of earthworm species registered for the country from 9 to 13 belonging to nine genera and three families. Out of the 13 species, 10 (Ap. caliginosa, Ap. jassyensis, Ap. trapezoides, Ap. rosea, Bimastus parvus, Dendrobaena byblica, D. fedtschenkoi, Eisenia fetida, Eis. tetraedra, and Lumbricus rubellus) belong to the Holarctic family Lumbricidae, two species (M. bahli and A. corticis) to the family Megascolecidae, and one species (D. annandalei) to Moniligastridae. Most of the species (10) are peregrine and only three of the lumbricid species in Afghanistan are regarded as autochthonous, viz., Ap. jassyensis, D. byblica, and D. fedtschenkoi. The diversity and distribution of earthworms in Afghanistan is far from complete. To fill this gap in our knowledge on the earthworm fauna of the studied region more detailed investigations are needed to explore the earthworm fauna of this vast country. [ABSTRACT FROM AUTHOR]

Earthworms are considered ecosystem engineers and, as such, they are an integral part of the soil ecosystem. The movement of earthworms is significantly influenced by environmental factors such as temperature and soil properties. As movement may directly be linked to food ingestion, especially of endogeic species like Aporrectodea caliginosa , changes in those environmental factors also affect life history traits such as growth and reproduction. In our laboratory studies, earthworms showed a decrease in burrowing activity with decreasing moisture levels and, to some extent, the organic matter content. The burrowing activity of earthworms was also affected by temperature, for which the casts produced per earthworm was used as a proxy in laboratory experiments. We integrated changes in earthworm movement and life histories in response to temperature, soil organic matter content and the moisture level, as observed in our experiment and reported in the literature, through dynamic energy budget (DEB) modelling. The joint parametrization of a DEB model for A. caliginosa based on movement and life history data revealed that food ingestion via movement is an integral part of the earthworms' energy budgets. Our findings highlight the importance of soil properties to be considered in the model development for earthworms. Furthermore, by understanding and incorporating the effect of environmental factors on the physiology, this mechanistic approach can help assess the impact of environmental changes such as temperature rise or drought. [ABSTRACT FROM AUTHOR]

Copyright of Egyptian Journal of Experimental Biology (Zoology) is the property of Egyptian Society of Experimental Biology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Earthworm invasions often reduce biodiversity and affect the ability of ecosystems to perform ecosystem functions. Over the past few decades, European lumbricid species have spread widely in natural habitats in Western Siberia, without completely displacing the native species. The aim of the present experiment is to study the survival, reproductive potential, vertical distribution, abundance, and biomass of Aporrectodea caliginosa and Lumbricus rubellus invasive species for the region and the native species Eisenia nordenskioldi and their influence on each other. For this purpose, winter and vegetation experiments were conducted in mesocosms simulating the real situation of invasions in the same communities on the same types of soils with the same amount and composition of litter. The authors found that the native species was significantly inferior to A. caliginosa in reproduction rate, number of offspring, and final biomass, but had an advantage over L. rubellus. The native species was positively influenced by the presence of A. caliginosa. In the experiment, there was a significant rejuvenation of the populations of the studied species, as well as an increase in abundance and relative mass under interaction conditions compared to mono variants. The native species had advantages over the invasive species in terms of winter survival. The natural volume of litter used in the experiment was insufficient for L. rubellus. According to the results of the experiment, it can be assumed that the spread of L. rubellus will continue to be limited to non-freezing biotopes rich in organic matter. A. caliginosa will spread in natural communities and agrocenoses of Western Siberia.

Aporrectodea caliginosa is a universally distributed and highly abundant peregrine earthworm that is the object of many ecological and ecotoxicological studies. Molecular phylogenetic analysis suggested that A. caliginosa consists of three highly diverged genetic lineages. In this study, we investigated morphological diversity within a sample of these three lineages from Belarus. We detected a variety of forms with different degrees of pigmentation and a shift in the clitellum position. The three genetic lineages of A. caliginosa demonstrated different propensity to particular morphological variants, including size, colour, and the clitellum position, yet no character could be used to distinguish among the lineages with sufficient accuracy. Thus, our results suggest that identification of the genetic lineage should be recommended for ecological studies involving A. caliginosa to account for possible differences between them. [ABSTRACT FROM AUTHOR]

The growing usage of plant protection products in agroecosystems questions their unintentional deleterious effects on non-target organisms such as earthworms and their related ecological function. The aim of this study was to investigate the turnover of soil microbiota during the gut transit of two endogeic earthworms (Aporrectodea caliginosa and Allolobophora chlorotica) and how it is possibly affected by the organophosphorus insecticide ethyl-parathion (Pt). We measured prokaryotic and micro-eukaryotic community composition and abundances using two different soil types in the continuum of bulk soil, gut and casts samples collected during and after one week exposure to Pt. The presence of earthworm and Pt had limited effects on the soil microbiota, although Pt altered temporarily soil microbial abundances in the presence of earthworms, not in their absence. The earthworms' gut harbored a remarkably low prokaryotic diversity, dominated by two molecular Operational Taxonomic Units (mOTUs) affiliated to Rhodococcus and Pseudarthrobacter. Contrastingly, gut micro-eukaryotic communities were maintained at diversity levels similar to that of the soil, yet Pt augmented their diversity and changed their composition. Fresh casts collected out of the soil revealed evident variation of abundance, diversity and community composition according to the soil origin and the earthworm species. In particular, following gut transit casts were enriched with Bacteroidia and γ-Proteobacteria while depleted of Acidobacteria. Exposure to Pt increased the diversity and relative abundance of depleted mOTUs, which paves the way for future investigations on the role of Pt in rising microbial consumption due to an over-excitation of gastrointestinal motility. • The earthworms' gut microbiome shows restricted bacterial and diversified micro-eukaryotic compositions. • The stimulation of specific micro-eukaryotes in casts depends on the earthworm species. • Microbial taxa depleted from soil during digestion reveal the earthworms' opportunistic feeding strategy. • Ethyl-parathion mostly affects the soil and casts microbiota and marginally micro-eukaryotes of the gut microbiota. • Ethyl-parathion modifies the digestive capacities of earthworms by enhancing depletion of microbes from soil. [ABSTRACT FROM AUTHOR]

Geographical parthenogenesis describes phenomenon when parthenogenetic hybrid forms or species have larger distribution areas or higher abundance than their amphimictic parental species, especially in climatically unfavorable conditions. This phenomenon was studied in Ukraine for the pair species of earthworms Aporrectodea caliginosa (Savigny, 1826) s. l. We found that the hermaphroditic amphimictic A. caliginosa clearly predominates in the northern and western regions, and the apomictic parthenogenetic A. trapezoides (Duges, 1828) in the southern and eastern regions with a continental arid climate. In the sample sets of A. caliginosa-A. trapezoides group, usually one of the species sharply predominated, and the equality of their abundance was very rare. The reason for this fact is both the alternative geographical distribution and the ability of A. trapezoides to form populations in habitats unfavorable for A. caliginosa. In general, the situation in this group agrees with the classical model of geographic parthenogenesis and confirms the high adaptive potential of apomictic organisms. This fact once again raises the question of non-adaptive reasons for the exclusion of the apomictic reproduction in highly organized animals. [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]

To achieve the EU's targets for reducing energy production from fossil fuels, the use of energy crops, such as Miscanthus × giganteus, is increasing resulting in a corresponding increase in waste ash from incineration. The chemical properties of Miscanthus ash (e.g. phosphorus and potassium content) may allow this waste material (currently landfilled) to be used as a fertiliser, but no information exists on the effect of the ash on the biological properties of soil. The main aim of this study was to determine the potential impact of Miscanthus ash on earthworms by assessing the effect on survival, change in biomass, reproduction and avoidance behaviour of the geophagous, soil dwelling earthworm, Aporrectodea caliginosa. Tests utilised a range of Miscanthus ash doses from 0 to 50 t ha−1 (0, 1, 2.5, 5, 10, 25, 50). Results showed that Miscanthus ash had no significant impact on A. caliginosa survival, biomass and reproduction, but negative trends were observed for biomass from 2.5 t ha−1 and for reproduction from 10 t ha−1. In contrast, a significant avoidance response was observed in the 25 and 50 t ha−1 treatment and according to ISO guideline 17512 there is a negative impact of the Miscanthus ash on soil habitat function at 25 t ha−1 and above as more than 80% of earthworms were in the control soil. It is suggested that this negative effect on soil habitat function could be attributed to a range of factors including the presence of heavy metals in the ash and a change in substrate pH, texture and/or osmotic stress. Further laboratory-based studies conducted over extended time periods with a more refined range of ash doses and associated field-based studies are required to validate the results and determine a more precise assessment of the threshold ash value inducing a loss of soil habitat function. [ABSTRACT FROM AUTHOR]

Copyright of Egyptian Journal of Experimental Biology (Zoology) is the property of Egyptian Society of Experimental Biology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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.)

In temperate ecosystems, earthworms and ants are the most important organisms for bioturbation. Little is known about how these groups contribute to bioturbation in different environments and to what extent overall bioturbation depends on their diversity. We developed a formula that allows quantification of annual earthworm bioturbation, thereby taking differences between earthworm ecotypes into account. With this formula, we calculated earthworm bioturbation at three sites, each with vegetation types typically found in Northern Europe. Earthworm bioturbation was low (1 Mg dry soil ha−1 y−1) in Scots pine and Norway spruce forests with acidic soil (pH 3.9–4.4) and high (between 15 and 34 Mg dry soil ha−1 y−1) in broadleaf forests, grasslands, alder carr and spruce forests on calcareous soil. Burrowing (endogeic and anecic) earthworms accounted for most of the earthworm bioturbation, and these worms had the highest population densities at moderate-to-high soil pH (pH 5–7.2). Estimates of ant bioturbation at the same sites were based on nest abundance, size and residence time. Mean ant bioturbation varied between 0.2 and 1 Mg dry soil ha−1 y−1, but individual plots had up to 2.4 Mg dry soil ha−1 y−1. In soils with pH higher than 5, the relative contribution of ants to total bioturbation was only 1–5%. Ant bioturbation was higher than earthworm bioturbation only in some forest soils with pH 3.9–4.4. Thus, earthworms appear to be the dominant cause of bioturbation in most types of terrestrial ecosystems in the cold-temperate areas of Europe and when information on local earthworm communities and monthly soil temperatures is available, bioturbation can be quantified using the presented 'earthworm bioturbation formula'. [ABSTRACT FROM AUTHOR]

In the Pampas region of Argentina agriculture is dominated by intensive no-till (NT) soybean cropping which produce negative consequences on soil quality. A group of farmers started to use the Good Agricultural Practices (GAP) which include a higher crop rotation, use of winter cover crops and nutrient restoration. In this NT system earthworms have a significant role in soil functioning, particularly in organic matter cycling and soil structure formation. The aim of this paper was to examine the contribution of earthworm activity to the process of C incorporation and soil structure maintenance in soils with different NT variants of: NT with GAP for 30 years (NT + r30); NT with some of the GAP for 12 years (NT-r12) and NT with soybean monoculture (NTm). Also a natural grassland (NA) was sampled as a reference. Earthworm aggregates were obtained by gently separating them from surrounding soil. Fine (HOC) and coarse (POC) organic matter fractions, water-stable aggregates (WSA) and mean weight diameter (MWD) were calculated for earthworm aggregates and bulk soil. In all sites only one species (Aporrectodea caliginosa) was found, with higher density in the NA, followed by NT + r30, that had about 9 times more earthworms than NTm. The number of earthworm aggregates was higher in the NT + r30 followed by the NA, both showing differences with the other NT systems. The earthworm aggregates in NA and NT + r30 had significantly more POC than the surrounding soil (230% increase in NA and 100% NT + r30). Earthworm casts had higher values of MWD and WSA than physical soil aggregates in both NA and NT + r30 management treatments. Our results show the existence of a positive feedback loop we called earthworm-driven virtuous cycle. The increase in earthworm abundance promotes higher production of earthworm aggregates which are richer in organic matter and more water stable than the surrounding soil. This has favourable results in terms of soil quality but also increase crop yields (57% in maize and 18% in soybean), by means of biologically mediated soil processes, which is a highly desirable way to sustainability of agricultural production. Farmers, politicians and the whole society should pay more attention to soil as a key component supporting agricultural production by means of internal biological soil functioning. • The only earthworm species present in all treatments was Aporrectodea caliginosa s.s. • No-till with good agricultural practices (NT + r30) had 9 times more earthworms than NT monoculture. • Cast density was higher in NT + r30 followed by the natural grassland (NA) and NT monoculture. • Particulate organic matter content was 230 in NA and 100% in NT + r30 higher in casts than in bulk soil. • In both, NA and NT + r30, casts were more stable to water than physical aggregates. [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]

Ecotoxicological tests with earthworms are widely used and are mandatory for the risk assessment of pesticides prior to registration and commercial use. The current model species for standardized tests is Eisenia fetida or Eisenia andrei. However, these species are absent from agricultural soils and often less sensitive to pesticides than other earthworm species found in mineral soils. To move towards a better assessment of pesticide effects on non-target organisms, there is a need to perform a posteriori tests using relevant species. The endogeic species Aporrectodea caliginosa (Savigny, 1826) is representative of cultivated fields in temperate regions and is suggested as a relevant model test species. After providing information on its taxonomy, biology, and ecology, we reviewed current knowledge concerning its sensitivity towards pesticides. Moreover, we highlighted research gaps and promising perspectives. Finally, advice and recommendations are given for the establishment of laboratory cultures and experiments using this soil-dwelling earthworm species. [ABSTRACT FROM AUTHOR]

Soil invertebrates are crucial for agroecosystem functioning yet sensitive to agricultural practices, including fertilization. Considering the postulates of circular phosphorus economy, the use of fertilizers from secondary raw materials is likely to return and increase and may even become obligatory. The effects of recycled fertilizers on soil fauna communities, however, remain poorly understood. In this paper, the effect of phosphorus fertilizer (RecF) and biofertilizer (RecB) from sewage sludge ash and dried animal (porcine) blood on earthworm’s occurrence in soil is discussed. RecB is RecF activated by phosphorus-solubilizing bacteria, Bacillus megaterium. Waste-based fertilizers were assessed in field experiments against commercial superphosphate and no P fertilization. Three levels of P doses were established (17.6, 26.4, and 35.2 kg P ha−1). Earthworms were collected after the test crop harvest (spring or winter wheat). In the experiments two earthworm species, Aporrectodea caliginosa and Aporrectodea rosea, were identified. A large proportion of juvenile individuals were recorded in 2017. The recycled fertilizers used in the experiments used in recommended doses, similarly to superphosphate, did not alter the density, biomass, species composition, and structure of earthworms. Further long-term field research is recommended.

Earthworms are important and useful soil organisms, but in agricultural soils, they are potentially exposed to a wide variety of pesticides. Insecticides represent the highest threat to earthworms and many are neurotoxic. There is a need for a reliable, relevant, simple biomarker to assess the sub-lethal effects of neurotoxic insecticides on earthworms under laboratory or field conditions. The Aporrectodea caliginosa earthworms were exposed to 0 (control), 0.5×, 1× (normal field application rate), and 5× concentrations of a carbamate (Pirimor®) and an organophosphate (Lorsban®) insecticides. The nerve conduction velocity (NCV) of the medial giant fibers of A. caliginosa earthworm was recorded on days 0, 1, 2, 3, 4, and 7 to quantify sub-lethal neurotoxic effects. Acetylcholinesterase (AChE) enzyme activity of A. caliginosa homogenates was measured at the conclusion of the experiment. Pirimor® but not Lorsban® induced a significant decrease in NCV on days 3, 4, and 7 at 1× and 5× doses. A significant dose-dependent decrease was observed on AChE activity to Pirimor® at the doses used but not Lorsban®. A clear relationship is observed between AChE activity and NCV in the case of Pirimor®. This study showed that NCV is a sensitive biomarker that correlates well with classical biomarker measurements such as AChE enzyme activity. This technique could be used to study the impact of insecticides on earthworms and also their recovery. [ABSTRACT FROM AUTHOR]

Earthworms are common organisms in the soil toxicity-testing framework, and the epigeic Eisenia andrei and E. fetida are the recommended species. However, Eisenia species are rarely found in agricultural soils and recent studies have pointed out endogeic species are more sensitive to pesticides than Eisenia . Allolobophora chlorotica and Aporrectodea caliginosa are two endogeic soil-dwelling species that are abundant in the agroecosystem. However, knowledge on pesticide impact on this ecological group of earthworms is still incipient. Herein, we compared the biochemical (acetylcholinesterase [AChE] and carboxylesterase [CbE] activities) and behavioral (burrowing, casting and feeding) biomarker responses of these two endogeic earthworm species exposed for 7 days to soils contaminated with 0.1, 1 and 10 mg kg −1 ethyl-parathion. The results showed marked species-specific differences in both groups of biomarkers, suggesting A. caliginosa the most sensitive species to this organophosphorus pesticide under the exposure conditions in this study. Moreover, an in vitro inhibition trial with ethyl-paraoxon evidenced a higher sensitivity of A. caliginosa AChE activity compared with that of A. chlorotica . This finding suggested that this molecular target endpoint could contribute to the interspecific differences of behavioral responses rather than CbE activity; this latter considered a potent mechanism of OP removal. Our results suggest the inclusion of more than one endogeic earthworm species to assess toxicity from organophosphorus insecticides. However, the use of A. caliginosa in the environmental risk assessment framework of organophosphorus contamination is highly recommended because of its higher sensibility to this class of pesticides, in addition to its abundance in the agroecosystem. [ABSTRACT FROM AUTHOR]

The 20-year dynamics of Aporrectodea caliginosa spring population parameters—the average density (ind./0.25 m2) and proportion of nonreproductive individuals (among earthworms found in 12 soil samples)— and the 10-year dynamics of their summer and autumn values were studied in an annually flooded alder forest in the Voronezh reserve. Three complete 3-year cycles and one complete 6-year cycle were revealed in the 20-year dynamics of spring population density. The 20-year series of average values of spring population density and proportion of nonreproductive individuals were found to be closely correlated with each other. A close correlation was also revealed between the 10-year series of summer density values and the corresponding dynamic series of summer precipitation. [ABSTRACT FROM AUTHOR]

The study aims to analyse the effects of the herbicide glyphosate (Roundup 360 ® ) on three key earthworm species. The taxa collected from treated and untreated sites were subsequently bred in uncontaminated soil terraria with serial concentrations of the herbicide. The chosen taxa included two anecic ( Lumbricus terrestris and Octodrilus complanatus ) and one endogeic ( Aporrectodea caliginosa ) earthworms. Lumbricus terrestris collected from uncontaminated soil (Lt1) and in a conventionally managed vineyard (Lt2). Aporrectodea caliginosa and Octodrilus complanatus collected from the same uncontaminated site where L. terrestris (Lt1) were collected. Uncontaminated natural grassland soil filling the terraria was characterized for physical-chemical properties. The reproduction rate expressed in earthworms cocoon production was the measure for the effects on worms survival after 21 and 42 days of exposure to 0.59, 2.9, 5.79 g/m 2 of glyphosate, where the dose applied in vineyards in the North-East of Italy goes from 0.72 g/m 2 to 4.32 g/m 2 . Earthworms in untreated terraria were found all alive, while specimens exposed to glyphosate (Roundup 360 ® ) showed a decreasing survival rate and a sharp decline in the number of cocoons. L. terrestris (Lt2) showed a survival rate between 64% and 92% after 21 days, and between 44% and 76% after 42 days. L. terrestris (Lt1) showed a lower resistance to herbicide (survival rate: 36%–84% after 21 days and 12%–76% after 42 days). A. caliginosa was also affected (survival rate: 32%–76% after 21 days and 12%–68% after 42 days). Glyphosate demonstrated severe effects on Oc. complanatus, collected on non-contaminated soils, with the lowest values of survival rate (33% after 21 days and 7% after 42 days of exposure). A significant reduction in the cocoons number (about 70%) was observed for L. terrestris (Lt1) and A. caliginosa after 21 days of exposure, whereas L. terrestris (Lt2) showed about 50% of cocoon production. Results indicate the occurrence of some resistance mechanisms on anecic earthworms in vineyards that have been exposed to glyphosate for at least three decades. However in spite of the long period of application of glyphosate the impact of this largely applied herbicide is still serious (up to 26% of mortality) especially on the deep-burrowing earthworms species ( Oc. complanatus and L. terrestris ). [ABSTRACT FROM AUTHOR]

Fermentation in combination with subsequent composting of biowaste is a preferred method for municipalities to recycle organic byproducts and transform them into useful end products for soil amelioration or plant fertilization. These compost products, especially if obtained from household wastes, can be a source of hazardous components, e.g. heavy metals, pathogens, synthetic chemicals or toxic organic compounds. An avoidance test with two earthworm species (Eisenia fetida and Aporrectodea caliginosa) was conducted to assess the impact of differently processed biowaste based digestate products on soil invertebrates. Body weight changes were recorded, as well as differences in effects on adult versus juvenile earthworms. While E. fetida showed no avoidance towards the digestate products (negative avoidance, meaning that the tested products were preferred, of 80 to 100 %), A. caliginosa rejected the crude biowaste digestate compost in higher concentrations (avoidance of 45 %), but not the agglomerated or pelletized variants. A clear weight gain of up to 25 % was observed only for individuals of E. fetida. The developmental stages of the worms were not crucial for the outcome of the avoidance test. Based on the results of this study the application of biowaste products on arable land cannot be recommended without constraints. [ABSTRACT FROM PUBLISHER]

Biological control of plant diseases through the addition of microbial biocontrol agents and the promotion of earthworms can be an environmentally friendly alternative to the chemical control of plant diseases. However, possible risks with biocontrol agents and their interactions with earthworms and other soil biota have not been well studied. The aim of this study was to assess whether the beneficial bacterium Bacillus amyloliquefaciens and the earthworms Aporrectodea caliginosa or Aporrectodea longa could reduce disease in oilseed rape ( Brassica napus ) challenged with the pathogen Alternaria brassicae. Plant growth and productivity were measured as plant survival, height, biomass, and flower development as well as disease index. A second objective was to assess whether the presence of the bacterium at high concentrations would influence the survival, growth, and reproduction of the earthworms. One outdoor and one greenhouse experiment were performed with Br. napus plants challenged with Al. brassicae inoculated to the plant leaves in the presence or absence of Bacillus amyloliquefaciens inoculated to the root environment and in the presence or absence of earthworms ( Ap. caliginosa or Ap. longa ) added to the soil. All treatments were replicated three times. In the outdoor experiment, inoculation with Al. brassicae reduced the growth of plants and the addition of Ap. caliginosa increased plant height. In the greenhouse experiment, pairwise comparisons of plants challenged with Al. brassicae showed that treatment with B. amyloliquefaciens led to significantly lower disease index than the treatment with Ap. caliginosa plus B. amyloliquefaciens , while other treatments had intermediate disease indices. The addition of Al. brassicae or B. amyloliquefaciens increased the survival and mass increment of Ap. caliginosa as a main effect when used separately but not when used in combination. This study did not give any clear indication of the usefulness of B. amyloliquefaciens for biocontrol of plant pathogens such as Al. brassicae when growing plants in natural soil. In addition, no significantly positive effects from the tested earthworm species were seen. [ABSTRACT FROM AUTHOR]

Fresh casts of endogeic earthworms are considered a hotspot of microbial activity that exhibit greater carbon mineralization (C min ) than the bulk soil. While cast properties depend on the ingested soil material, little is known about how earthworm feeding behavior and digestive processes interact with those properties to determine the C min in fresh casts egested by endogeic earthworms. Two laboratory experiments were designed to (i) assess the short-term changes in C min of soil and fresh casts after the soil or soil physical size fractions passed through the gut of Aporrectodea caliginosa , a common endogeic species in temperate agroecosystems, and (ii) to determine whether these changes depended on initial properties of the ingested materials. In the first experiment, we determined how C min was affected by gut passage (i.e., casts vs. bulk and surrounding soil) and soil type (three sandy-loam soils with variable content of light fraction organic matter (LF): the Courval, St. Amable and Chicot soil series). In the second experiment, we related C min in casts to the interactive effect of the gut passage and soil fraction size (Courval soil series only). Six soil treatments were examined: whole soil and five-soil fraction size classes (2000–1000 μm, 1000–500 μm, 500–250 μm, 250–53 μm and <53 μm). As hypothesized, the earthworm gut transit increased C min in casts by two to three-fold relative to the bulk soil and surrounding soil, and the increase in cast C min was soil- and soil fraction size-specific. The C min in casts was significantly (p < 0.05) greater in the finest soil fraction (<53 μm) and lowest in the intermediate fraction (500–250 μm) compared to the whole soil and other soil fractions. Additionally, the priming effect of earthworm ingestion and digestion processes, estimated by the normalized C min for casts (which subtracts the baseline C min flux from the bulk soil or soil fraction) was positively correlated (p < 0.05) with the C concentration of the LF in the ingested soil. This suggests that A. caliginosa derive their nutrition from the LF, and that the 500–250 μm fraction is the optimal size to support their nutritional requirements. [ABSTRACT FROM AUTHOR]

Partitioning tissue metal concentration into subcellular compartments reflecting toxicologically available pools may provide good descriptors of the toxicological effects of metals on organisms. Here we investigated the relationships between internal compartmentalization of Cd, Pb and Zn and biomarker responses in a model soil organism: the earthworm. The aim of this study was to identify metal fractions reflecting the toxic pressure in an endogeic, naturally occurring earthworm species (Aporrectodea caliginosa) exposed to realistic field-contaminated soils.After a 21 days exposure experiment to 31 field-contaminated soils, Cd, Pb and Zn concentrations in earthworms and in three subcellular fractions (cytosol, debris and granules) were quantified. Different biomarkers were measured: the expression of a metallothionein gene (mt), the activity of catalase (CAT) and of glutathione-s-transferase (GST), and the protein, lipid and glycogen reserves. Biomarkers were further combined into an integrated biomarker index (IBR).The subcellular fractionation provided better predictors of biomarkers than the total internal contents hence supporting its use when assessing toxicological bioavailability of metals to earthworms. The most soluble internal pools of metals were not always the best predictors of biomarker responses. metallothionein expression responded to increasing concentrations of Cd in the insoluble fraction (debris + granules). Protein and glycogen contents were also mainly related to Cd and Pb in the insoluble fraction. On the other hand, GST activity was better explained by Pb in the cytosolic fraction. CAT activity and lipid contents variations were not related to metal subcellular distribution. The IBR was best explained by both soluble and insoluble fractions of Pb and Cd.This study further extends the scope of mt expression as a robust and specific biomarker in an ecologically representative earthworm species exposed to field-contaminated soils. The genetic lineage of the individuals, assessed by DNA barcoding with cytochrome c oxidase subunit I, did not influence mt expression. [ABSTRACT FROM AUTHOR]

Earthworm activity can strongly influence soil structure and organic matter (OM) dynamics of agricultural soils. Several short-term studies (≤90 days) have shown that earthworms can increase incorporation of residue carbon (C) into soil aggregates, suggesting reduced decomposition in the longer term. In contrast, another body of short-term studies reported that earthworms can increase carbon dioxide (CO 2 ) emission from soils, thus suggesting increased decomposition in the longer term instead. To solve this controversy, we measured the effect of the epigeic Lumbricus rubellus (Hoffmeister) and the endogeic Aporrectodea caliginosa (Savigny) on the soil C balance in a unique 750-day mesocosm experiment, where loess soil was surface-applied with maize ( Zea mays L.) residues every six months. Carbon inputs and outputs were strictly controlled: no soil C input through growing plants and no leaching of soil organic C. Flux measurements of CO 2 were taken regularly and aggregate size distribution and total C and residue-derived C in the aggregate fractions (using the natural δ 13 C signature of maize) were measured after 185, 565 and 750 days. Both earthworm species increased cumulative CO 2 emissions by at least 25%, indicating a higher C loss compared to the no-earthworm control. Yet, both earthworm species also increased the amount of soil C associated with the macroaggregate fraction after 750 days. L. rubellus increased the amount of residue-derived C in the macroaggregate fraction after 565 and after 750 days, whereas A. caliginosa increased residue-derived C in all the measured soil fractions after 750 days. Our results show that earthworms can simultaneously enhance CO 2 emissions and C incorporation in aggregate fractions. However, over 750 days the presence of earthworms resulted in a lower total C content due to a higher overall OM decomposition rate. We therefore propose that under the most realistic incubation conditions so far (longer term and multiple residue applications), earthworms stimulate the mineralization of freshly added and older OM to a greater extent than that they stabilize residue-derived C inside biogenic aggregates. Future studies should focus on the balance between these processes in the presence of growing plants. [ABSTRACT FROM AUTHOR]

It is difficult to obtain non-destructive information on the seasonal dynamics of earthworms in northern forest soils. To overcome this, we used a Rhizotron facility to compile 7 years of data on the activity of anecic ( Lumbricus terrestris) and endogeic ( Aporrectodea caliginosa complex) earthworms in two contrasting soil/plant community types. We hypothesized that L. terrestris burrows would be used for longer than a typical L. terrestris lifetime, and that the distribution and activity pattern of the two earthworm species would respond differently to changes in soil moisture and temperature. For 7 years we recorded earthworm distribution and activity state bi-weekly to a depth of 1.5 m, tracked L. terrestris burrows using images captured annually, and measured soil temperature and moisture. Activity and vertical distribution of earthworms was closely linked to earthworm species and soil temperature in the fall, winter and spring. Lumbricus terrestris typically remained active through the winter, whereas the A. caliginosa complex was more likely to enter an aestivation period. Activity of all earthworms decreased substantially in July and August when soil temperature was at its highest and soil moisture at its lowest for the year. Most L. terrestris burrows were used continuously and moved very little during the 7-year study, likely creating spatiotemporally stable hotspots of soil resources. The different patterns of response of these species to soil temperature and moisture suggests that endogeic earthworms are more likely than anecic earthworms to adjust activity states in response to climate change mediated shifts in soil moisture and temperature. [ABSTRACT FROM AUTHOR]

Mild electrostimulation of earthworms is commonly used for harvesting celomocyte-containing celomic fluid. We have noticed that frequent electrostimulations of worms can lead to the autotomy of posterior segments followed by their regeneration. Our present study aim was to develop an autotomy model in the eco-physiologically contrasting species, Eisenia andrei and Aporrectodea caliginosa, using direct current (DC), pulsating direct current (PDC), or immersion in the noxious anaesthetic MS222. A. caliginosa was clearly more susceptible to autotomy than E. andrei, with both electrostimulation regimes and MS-222 exposure inducing autotomy in the former species but only repeated PDC stimulations inducing segment loss in the latter. The observations lend credence to the hypothesis that autotomy in earthworms is caused by factors impinging upon the nervous system; they also indicate that repeated PDC stimulations could be an effective and reproducible means of facilitating segmental autotomy so that the fundamental cytological and molecular-genetic mechanisms underpinning the tissue loss event and subsequent regeneration can be studied in depth.