Different Species Of Earthworms Research Articles

Xenobiotic Bioconcentration in Terrestrial Oligochaetes to Evaluate Soil Quality

Excessive use of pesticides, heavy metals, and detergents may have negative effects on non-target organisms in soil and water and may seriously harm ecosystems. A total of 181 earthworm specimens from various habitats were gathered from three separate locations, namely the Anthikkad and Chalakudi locality in the Thrissur district and the Meenangadi locality in Wayanad. We were able to identify four different earthworm species which belonged to two distinct families and four different genera. Thereafter from this study it was clear that the Density of different species of earthworm (P. sansibaricus and L. mauritii) collected from study areas are same. Pb was found to be undetectable in earthworm samples from study sites out of the four pollutants evaluated. Earthworm samples from Anthikkad and Meenangadi sites had the greatest levels of the heavy element Zn. Of the 32 pesticides tested, 4 organochlorine pesticides and 4 organophosphorus pesticides were found to be at in samples collected from two different districts. By statistical analysis it was concluded that soil samples from all the sites (As, Cs & Ms) were homogeneous. It is not essential to be exposed to a large concentration of xenobiotics for the bodily tissues to become toxic; by extending the exposure period, the concentration can rise to dangerous levels. One more sensitive and early-warning biomarker of ecosystem health is the observation of earthworm immunological capability.

Earthworms increase soil greenhouse gas emissions reduction potential in a long-term no-till Mollisol

Earthworm activity and plant residues in the soil can strongly influence soil organic carbon (SOC) dynamics. However, studies on how earthworms, especially epigeic and endogeic species alone or together, affect the main soil greenhouse gas (GHG) emissions (CO2 and N2O) and SOC under the long-term no-till (NT) and conventional tillage (CT) in Mollisols in Northeast China are unclear. The effects of two different species of earthworms (epigeic, Eisenia nordenskioldi; endogeic, Metaphire tschiliensis) on the soil GHG emissions and the SOC content were studied in NT and CT soils in a 337-day mesocosm experiment. The presence of earthworms enhanced the soil cumulative CO2 and N2O emissions in both NT and CT soils, and the soil GHG emissions (expressed in terms of the global warming potential, GWP) were increased by 20.43 %–42.99 % in NT soil and by 0–55.62 % in CT soil, respectively. Compared to E. nordenskioldi, the presence of M. tschiliensis (endogeic species) significantly increased soil GHG emissions. Earthworms in NT soil induced less soil GHG emissions than those in CT soil. The presence of earthworms did not increase the SOC content in CT soil but significantly increased the SOC content in NT soil. Our study suggests that earthworms in the long-term no-till soil can contribute to the reduction of soil GHG emissions. This research helps to understand the effects of different ecological categories of earthworms on soil GHG emissions and SOC dynamics under different tillage systems and to mitigate soil GHG emissions.

Responses of earthworms exposed to low-density polyethylene microplastic fragments

The interest in the effect of microplastics (MPs) on the terrestrial environment has been increasing recently. Different species of earthworms have been used to study the effects of MPs on different aspects of earthworm health. However, there is still a need for more studies because different studies report different effects on earthworms depending on the properties (e.g., types, shapes, sizes) of MPs in the environment and exposure conditions (e.g., exposure period). This study used Eisenia fetida as a test earthworm species to investigate the effect of different concentrations of low-density polyethylene (LDPE) MPs (≤125 μm) in soil on the growth and reproduction of earthworms. The exposure of the earthworms to the different concentrations of LDPE MPs (0–3% w/w) for 14 d and 28 d neither caused death of the earthworms nor showed significant effects on the earthworm weights in this study. The number of cocoons produced by the exposed earthworms were also similar to that of the controls (i.e., no exposure to MPs). Some previous studies reported similar results to what have been observed in this study, while some studies reported different results. On the other hand, the number of ingested MPs by the earthworms increased with increasing MPs concentrations in soil, suggesting a potential for damage to digestive tract. Also, the earthworm skin surface was damaged after exposure to MPs. The ingested MPs and the skin surface damage suggest that there is a potential for adverse effects on the earthworm growth after a longer-term exposure. Overall, the results of this study show that the effects of MPs on earthworms need to be studied using various endpoints including growth, reproduction, ingestion, and skin damage and such effects can be different depending on the exposure conditions such as MPs concentration and exposure period.

Optimization and scale up of the enzymatic hydrolysis of Californian red worm protein (Eiseniafoetida)

Although the best-known use of the different species of earthworm is the production of organic fertilizer, they can also be considered a rich source of biologically and pharmacologically-active compounds, for use in the treatment of various diseases. In recent decades, with the development of biochemical technologies, research on the pharmaceutical effects of compounds extracted from different species of earthworms has begun. Enzymatic hydrolysis is the most common and widely used technique for producing bioactive hydrolysates, because it uses moderate operating conditions, with a certain specificity for the substrate. In the present study, the objective was to optimize and scale up the enzymatic hydrolysis of Eisenia foetida protein to obtain peptides with biological activity. The substrate characterization was carried out according to AOAC, a response surface design was performed for the optimization of the enzymatic hydrolysis and then the scaling was performed by means of dimensional analysis. The results show that the major component of the paste is protein, 65% of which is albumin, and the absence of pathogenic microorganisms was also found. Regarding optimization, it was found that the optimal hydrolysis conditions are achieved with pH = 8.5; temperature = 45 °C; amount of substrate = 125 g and volume of enzyme = 1245μL. For the scaling, 4 dimensionless pi-numbers were calculated which describe the process with no statistically significant differences between the model and the prototype; it can be concluded that the enzymatic hydrolysate of Eisenia foetida presents high values of antioxidant activity evaluated by different methodologies.

NEUROSECRETION IN OLIGOCHAETES - A LESS STUDIED SUBJECT IN INVERTEBRATE RESEARCH

The concept of neurosecretion was first developed by Ernst Scharrer (1905-1965) and Berta Scharrer (1906-1995) between 1928 and 1937. The neurosecretory cells are neuronal in structure and glandular in function. Typically, the neurosecretory cells are “tear drop” in appearance with a long axon. The neurosecretory products (neurosecretion/neurohormone) are proteinaeous in nature which is consistent with the ultrastructure of the cells
 In earthworm species, irrespective of their ecological categories, the neurosecretory cells in their distribution, structure and functions in the central nervous system are more or less similar in different species of earthworms. The central nervous system in tropical earthworms reveals mainly two types of neurosecretory cells: A type (outer cortical tier of deeply stained AF positive cells with distinct axonal processes) and B type (light stained cells lying in between A type cells and central fibrous neuropile). In addition to A and B cells, an “islet” of neurosecretory cells called S cells or Hubl cells are present at the base of circum esophageal connectives of subesophageal ganglia. Both A and B cells discharge their secretion (neurohormone) at the margin of highly vascularised fibrous neuropile called “zone of accumulation” which may be considered as “elementary neuro-haemal organ”. Neurosecretion in Oligochaetes has great role in food intake, osmoregulation, thermal acclimation, regeneration, copulation and cocoon production.

Molecular Characterization and Phylogenetic Analysis of Earthworm Species Collected from Different Soil Habitats of Poonch Division Azad Jammu and Kashmir Pakistan.

This study aims to analyze molecular characterization and phylogenetic analysis of earthworm species collected from different soil habitats of Poonch division Azad Kashmir Pakistan by using CO1 gene partial sequencing methodology. Samples gathered randomly from 18 study sites (127 localities) by digging and hand sorting methods were preserved in pure ethanol at -20°C. The modified CTAB (Cetyltrimethyl ammonium bromide) method extracted high quality DNA from region of representative earthworm's caudal region. This extracted DNA was used to amplify the 700 bp partial region of the cytochrome oxidase I (COI) gene with LCO1490 and HCO2198 universal primers. All of the obtained amplified gene sequences were aligned, edited and analyzed using MEGA X software to characterize different species of earthworms. Thirty-eight (38) Barcoding sequences belonging to 11 different strains of earthworms were successfully generated. Their phylogenetic analysis revealed that 7 Barcoding sequences gave maximum similarity with the available online database, while the rest of the 4 sequences gave lower similarity than the maximum threshold level. The collected DNA barcode sequences were also clustered together by the maximum likelihood method and the resultant phylogenetic tree revealed they belong to different family lineages. Moreover the identified earthworm species have a close evolutionary link with the earthworm fauna of south and central Asia instead of Europe, which might be due to similar climate of both regions.

An annotated checklist of Earthworms from India

Earthworms belong to Phylum Annelida, Class Oligochaeta are truly coelomate animals and are known to be swell dwellers. They are exposed to pathogens in the soil. Global in distribution, they reveal biodiversity across India. We have studied the earthworm fauna of India and present here a total distribution of different species of earthworm from India, highlighting their biodiversity and ecology. The study of diversity and earthworm distribution across different states of India and different soil conditions, included under 20 agroeconomic zones (AEZ) of India including 14 families and 445 valid species is an intriguing study, being reported for the first time from India.

Do organic additives stimulate specific body weight gain and reproductive parameters of Earthworms Eisenia fetida and Aporrectodea caliginosa?

Food resource availability is one of the most important factors affecting the performance and different activities of earthworms. Thus the present study focuses on testing the biological responses of two different species of earthworms one of them represents an epigeic forms Eisenia fetida and the other belongs to edaphic (Aporrectodea caliginosa) towards a mixture of organic substances of rice straw, cow dung, leaf litter, sawdust, banana peel, and kitchen waste. Specific body weight gain (SBWG) and different reproduction parameters were measured in relation to the diet quality of organic additives. Significant effects of the used organic additives on different studied parameters of both worm species could be recorded. The two earthworm species showed different responses toward the organic additives. In conclusion, it could be suggested that species specificity, worm’s ecotype, as well as food resource availability, are the main factors controlling worm biomass and different earthworm activities.

A novel high-rate vermicomposting machine for downstream processing of biorefinery waste and other forms of organic solid waste

A novel machine, with the acronym HEVSTOW (high-efficiency vertically stacked vermicomposting system for treating organic waste), of which a patent has recently been granted, is described. It is capable of rapid, inexpensive, and emission-free processing of biorefinery waste and other forms of organic solid waste. The machine is based on the paradigm of high-rate vermicomposting earlier developed by the authors. It makes it possible to rapidly process biorefinery waste of plant origin, as also paper, which the conventional vermireactors are not able to handle without elaborate pre-treatment and/or augmentation of animal manure. The machine also makes it possible to simultaneously vermicompost different forms of biowaste as also use different species of earthworms in such a manner that each batch operates independently without one batch interfering with the other. The applicability of the machine has been demonstrated by its application in simultaneous yet independent processing of a biorefinery waste, and paper waste, each with two epigeic species of earthworms Eisenia andrei and Lumbricus rubellus.

Avoidance behavior of Eisenia fetida and Metaphire posthuma towards two different pesticides, acephate and atrazine

The avoidance behavior is regarded as the method that provides first hand information about the behavior of an organism in the presence of contaminants in the soil. Very little data is found in literature regarding the effect of pesticides on tropical earthworms. Two pesticides, acephate and atrazine which are widely used in Indian tropical area were investigated for their avoidance behavior on standard species, E. fetida (ISO 2007) and on a tropical species, M. posthuma. The avoidance tests are rarely replicated on tropical species, M. posthuma in comparison to standard species, E. fetida or E. andrei. The standard avoidance test (ISO 2007) was taken into consideration for two different species of earthworm. Significant difference in the distribution of earthworms in the control and test soils was found depicting that soil composition plays a vital role in affecting the distribution of worms. The results also show higher sensitivity of E. fetida in comparison to M. posthuma in terms of avoidance response for both the pesticides. For risk assessment, the soil types and indigenous soil species of earthworms must be taken into consideration for evaluation of soil contamination. Avoidance tests forms the basis to study the molecular mechanisms underlying the receptor proteins responsible for the process of chemesthesis in annelids.

Interaction of land use history, earthworms, soil chemistry and tree species on soil carbon distribution in managed forests in Vermont, USA

Forest soils store a globally important pool of carbon (C) and reforestation has the potential to increase this pool. Past land use, tree species composition, and current management are known to affect carbon storage rates and amounts. Another important factor, especially in the vertical distribution of soil C, is the presence or absence of earthworms. We investigated these interactions in eighteen managed forest sites in Vermont that have varied land use history (cultivation, pasture, woodlot, continuous woodland) and a range of time since reforestation from 60 to 100+ years. Soils were sampled to about 1 m, or shallower if bedrock was reached, and both C and exchangeable cation pools quantified. Earthworms were enumerated to a depth of 20 cm and identified by species. Basal area by tree species was also measured and aboveground C calculated. Detailed land use history was documented using archival sources. Forest type was primarily northern hardwood, with a few lowland spruce-fir sites included. Eleven different species of earthworms were found, representing all ecotypes, and numbers ranged from 0 (at 8 of the 18 sites) to 319 individuals/m2. Carbon pools in the forest floor (1.5–30.1 Mg/ha) were greater with higher site elevation (range of 154–651 masl) and also greater with lower numbers of earthworms. Besides elevation, the best predictor of earthworm presence or absence, and overall numbers, was the soil exchangeable calcium (Ca) pool in the Oa and A horizons (range of 9.4–1288 cmolc/m2). Because soil exchangeable Ca and aluminum (Al) pools were inversely related, higher exchangeable Al was associated with lower earthworm numbers. In the mineral soil, the C pool (82.1–210.8 Mg/ha) was best explained by the thickness of the B horizons with the exchangeable Al pool as a positive, secondary factor. The thickness of the A horizon (0–16.3 cm), and its contribution to the entire profile C pool (0–54.7 Mg/ha), decreased relative to past land use in the order: cultivated < pasture < woodlot. No earthworm metric was strongly related to the C pool in either the mineral soil or the full soil profile. Dramatic differences in the vertical distribution of carbon were related to past land use and earthworm presence, which in turn was negatively correlated with elevation and the presence of conifers. While it is clear that earthworms and prior land-use have a long-lasting effect on the forest floor C pool, it is less clear whether or not there is an effect on full profile C sequestration over time.

Fate of chemical constituents of prosopis leaves during the conversion of the leaves into an organic fertiliser

ABSTRACT When the otherwise toxic and allelopathic leaves of prosopis (Prosopis juliflora) are vermicomposted, the end product becomes a benign organic fertiliser. This paper describes extensive analytical studies, based on Fourier transform infrared spectroscopy, thermal analysis, and gas chromatographic-mass spectroscopic analysis, carried out to identify the change in the chemical composition of prosopis leaves that occur as the leaves go through biodegradation. All the studies indicate that a transformative change is seen to occur, leading to the breakdown of allelochemicals and other toxic ingredients into simpler molecules that are not known to be toxic. There is also a major shift in the arrangement of the molecules. Vermicompost derived from six different species of earthworms yielded similar results indicating the general applicability of the present findings. Scanning electron microscopy revealed that vermicomposting causes the otherwise robust and regular surface of prosopis leaves to get withered, thereby increasing their surface areas and making them more amenable to biodegradation.

Potential utilization of various organic waste additives in vermicomposting using two different earthworm species

The aim of the present study is to test the null hypothesis that the composting potential of the adult earthworm is mainly species-specific processes. In order to realize this hypothesis, two different species of earthworms; one epigeic; Eisenia fetida, and the other edaphic; Aporrectodea caliginosa were chosen in this study. Different organic additives were used consisting of (rice straw, leaf litter, sawdust, kitchen waste, and banana peel) to enrich bedding for vermicomposting systems in addition to cow dung. Vermicompost formed were assessed across different periods during vermicomposting process. The obtained results revealed that the addition of organic additives to vermicomposting system increase the moisture content and nutrient concentrations (N, P, K and Ca) in produced vermicompost. Contrarily, pH, OM, OC and C/N ratio decreased significantly during vermicomposting process. The quality of vermicompost was higher in vermicomposting processed by E. fetida than in case of A. caliginosa. Moreover, organic additives enhanced the characteristics of end product of vermicomposting process.

Assessment of earthworm activity on Cu, Cd, Pb and Zn bioavailability in contaminated soils using biota to soil accumulation factor and DTPA extraction.

The study aims to investigate effect of earthworm activity on metal bioavailability in soils using their BSAF-metals. Based on a microcosmic laboratory experiment, epigeic species Amynthas corticis (A. corticis) and endogeic species Amynthas robustus (A. robustus) were cultured in two types of soils contaminated by Cd, Zn, Pb and Cu for 120 days. Earthworm characteristics (i.e. numbers, biomass and BSAF), soil properties (i.e. pH, organic C and N contents along with their components such as mineralization and microbial masses) and DTPA extracted metals in soil were determined. After the incubation, the biomass and survival numbers of both earthworm species decreased significantly (P<0.05). The accumulation of Cd, Zn and Pb in earthworm tissues and BSAF-metals were earthworm species dependent. According to two-way ANOVA, BSAF-Pb clearly showed the effect of different species of earthworms while BSAF-Cu indicated an interactive effect of earthworms and soil type. Earthworms changed soil properties significantly, especially for mineralized C (Cmin), dissolved N (Ndis) and pH (P<0.05). Earthworm activity increase DTPA extracted Zn and Cu, and the effect of A. robustus were stronger than for A. corticis. Redundancy analysis (RDA) showed that BSAF-Cu and BSAF-Pb contributed for respectively 51.9% and 51.7% of soil properties and DTPA metal changes, indicating that the effects of BSAF-Cu and BSAF-Pb on soil properties and on metal bioavailability in soil were similar. BSAF-Cu, indicating the interactive effect of earthworms and soil, accounted for 38.5% and 45.1% of soil properties and soil metal bioavailability changes. BSAF-Pb, representing the effect of earthworm species, accounted for 13.3% and 6.6% of soil property and soil metal bioavailability variations. Stepwise regression indicated that earthworm might change soil properties through their activities and interactions with soil, and hence increase heavy metal bioavailability. It suggested that BSAF is an important indicator for evaluating the effect of earthworm activity on soil metal bioavailability and designing remediation strategies.

Insilico Studies on Antimicrobial Peptides (AMPs) from Earthworm

The immune system of earthworm is very robust despite being in a primitive invertebrate organism. The immune system confers protection against pollutants and pathogens (Ghosh in Environ Sci Pollut Res 25:6196, 2018) and the cells and molecules in the earthworm coelomic fluid are reported (Bilej et al. In: Madame Curie bioscience database [Internet]. Landes Bioscience, Austin, TX, 2000–2013) to play antibacterial, antitumoral and anti trypanosomal role and contain immune molecule including coelom cytolytic factor (CCF), lyesenin and antimicrobial peptides (AMPs). Due to their diverse and advanced roles, they find importance for study both from the point of view of basic sciences and applied biological sciences. Although the immune molecules are reported from different species of earthworm, the physiochemical proteins of AMPs are yet to be studied. Therefore, we performed an insilico study of the different AMPs reported from different species of earthworm from the NCBI. We report for the first time, diversity amongst the AMPs of different species of earthworms, despite functional similarities.

Earthworm Diversity in Laterite and Regur Soil of Deccan Trap of Hyderabad–Karnataka Region, Karnataka, India

Earthworm survey was conducted across Bidar district that contains solidified lava and forms the part of Deccan trap of Hyderabad–Karnataka Region. Earthworm samples along with their habitat soil were collected by digging and hand sorting method from the selected spots like gutter, garbage, near bore well, near tap, garden, pasture, drainage system and fields. Ten different species of earthworms were identified viz., Eudrilus eugeniae of the family EUDRILIDAE; Lampito mauritii and Perionyx sansibaricus of the family MEGASCOLECIDAE; Dichogaster bolaui, D. modiglianii, Eudichogaster ashworthi, E. prashadi, E. poonensis, Octochaetona beatrix and O. paliensis of the family OCTOCHAETIDAE. Among these the genus Eudichogaster is found to be the most dominant and widely distributed earthworm in Bidar district. Eudichogaster poonensis is reported for the first time from South India. Soil chemical characteristics of their habitat were pH 6.7–8, electrical conductivity (EC) 0.28–1.16 mohs/cm, organic carbon (OC) 0.75–3.54%, nitrogen (N) 25.2–118 kg/acre, phosphorous (P) 6.6–48.8 kg/acre and potassium (K) 79–354 kg/acre. Earthworms inhabiting in the laterite soil showed wider range in the soil chemical characteristics, pH ranged from slightly acidic to alkaline; whereas earthworms inhabiting in regur soil of this region showed narrow range in the soil chemical characteristics.

The release and earthworm bioaccumulation of endogenous hexabromocyclododecanes (HBCDDs) from expanded polystyrene foam microparticles

Hexabromocyclododecanes (HBCDDs) are common chemical additives in expanded polystyrene foam (EPS). To evaluate the bioaccumulation potential of endogenous HBCDDs in EPS microparticles by earthworms, two ecologically different species of earthworms (Eisenia fetida and Metaphire guillelmi) were exposed to soil added with EPS microparticles of different particle sizes (EPS2000, 830–2000 μm and EPS830, <830 μm). To clarify the accumulation mechanisms, leaching experiments using EPS microparticles in different solutions were conducted. After exposure to EPS microparticles-amended soils (S-EPS) for 28 d, the total concentrations of HBCDDs reached 307–371 ng g−1 dw in E. fetida and 90–133 ng g−1 dw in M. guillelmi, which were higher than those in earthworms exposed to the soil that was artificially contaminated with a similar level of HBCDDs directly (ACS). The accumulation of HBCDDs in earthworms was significantly influenced by EPS microparticles' size and earthworms' species. The total concentrations of HBCDDs in earthworms' cast were significantly higher than the theoretical concentration of HBCDDs in S-EPS, which suggested that EPS microparticles can be ingested by earthworms. The release rate of HBCDDs from EPS5000 (2000–5000 μm) into water-based solutions (<1%) after a 3.5-h incubation was far lower than that into earthworm digestive fluid (7%). These results illustrated that the ingestion of EPS microparticles and consequent solubilization of HBCDDs by digestive fluid play an important role in the accumulation of HBCDDs contained in EPS microparticles in earthworms. After a 28-d incubation with the soil solution, 4.9% of the HBCDDs was accumulatively leached from the EPS5000, which indicated that HBCDDs can be released from EPS microparticles to soil environment, and then accumulated by earthworms. Moreover, similar to those exposed to ACS, the diastereoisomer- and enantiomer-specific accumulation of HBCDDs in earthworms occurred when exposed to S-EPS. This study provides more evidence for the risk of microplastics to the soil ecosystem.

Phenanthrene Mitigates Cadmium Toxicity in Earthworms Eisenia fetida (Epigeic Specie) and Aporrectodea caliginosa (Endogeic Specie) in Soil.

In classical toxicology studies, the interaction of combined doses of chemicals with dissimilar modes of toxic action in soil is complex and depending on the end point investigated and the experimental protocol employed. This study was used to examine the interactive effect of phenanthrene and Cadmium on two ecologically different species of earthworms; Eisenia. fetida and Aporrectodea. caliginosa. This interactive effect was scrutinized by using the acute toxicity test with the concentrations of 2.51 mg kg−1 and 3.74 mg kg−1, respectively, being lethal for 50% of E. fetida and A. caliginosa. The results showed that in the mixture treatment, phenanthrene at 5, 10, 15 and 20 mg kg−1 significantly mitigated both earthworms species mortality and body-mass loss. Moreover, the factor of Cd accumulated in E. fetida and A. caliginosa tissues was significantly decreased by about 12% and 16%, respectively. Linear regression correlation coefficient revealed that the reduction of both earthworm species mortality was negatively and significantly correlated (r2 = 0.98 ± 0.40 and 1 ± 3.9 p < 0.001) with phenanthrene concentration in soil. However, over 20 mg kg−1 of phenanthrene, both organisms mortality rate increased again, as was the Bioaccumulation factor of phenanthrene. Thus, this study proposes that the antagonistical effect of phenanthrene on Cd at a degree of concentration can be used to mitigate Cd effect on soil living organisms. However, as an implication of these results, the interpretation of standardized toxicity bioassays, including whole effluent toxicity tests and single-compound toxicity tests, should be performed with caution. In addition, risk assessment protocols for environment pollution by a mixture of metals and polycyclic aromatic hydrocarbons should include robust methods that can detect possible interactive effects between contaminants to optimize environmental protection.

Vermicomposting of aquatic weeds: A quick review

Aquatic plants play an important role in ecosystem functioning and services but they can also be deleterious if present in excess. The different anthropogenic activities result in accumulation of nutrients in aquatic ecosystems leads to eutrophication with massive weed growth and associated diverse adverse effects. Effective control/management of weeds in different aquatic systems is not only difficult but of short duration. The commonly used methods to manage/control the aquatic weeds are biological, chemical and mechanical, in addition to habitat manipulation. However, these methods can be highly disruptive causing adverse environmental effects and are relatively inefficient. On the other hand different species of earthworms can feed on wide range of weeds and convert them into stable product called vermicompost, rich in plant nutrients. Among different aquatic weeds the most extensively vermicomposted weed is water hyacinth (Eichhornia crassipes (Mart.) Solms), using different earthworm species. Among different earthworm species used for vermicomposting of aquatic weeds, Eisenia fetida (Savigny) is the most commonly used species. Vermicomposting is an efficient ecobiotechnological process that converts the aquatic weeds into nutrient rich material that can acts as suitable plant growth media for sustainable agroecosystems. Further large scale utilization of aquatic weed based vermicompost in horticulture can solve their management and disposal issues along with restoration of organic matter and nutrient depletion at low input basis.

EARTHWORM BIODIVERSITY IN DIFFERENT LAND USE SYSTEM

Researches have proved that the occurrence of different species of earthworms in good numbers is a positive sign of healthy soil. Establishment of earthworm population makes the soil more compact and the poor structure of deep soil changes in to friable top soil. Twenty two species of earthworms are identified from different land use systems. The potential soil reclaiming species are Eutyphoeus incommodus, Eutyphoeus nicholsoni, Eutyphoeus waltoni, Octochaetona surensis, Amynthas morrisi, Metaphire posthuma and Lampito mauritii. Metaphire posthuma is very abundant in garden soils. Eutyphoeus nicholsoni is mostly confined to garden litter soil with medium and low population as deep burrowing species. Octochaetona surensis is very common in dense bamboo plantations. Amynthas morrisi is mostly confined to decomposing paddy straw and composting litter. The cultivated soils of sugarcane and jowar, the species association index of Eutyphoeus incommodus and Ramiella naniana is very high though Ramiella naniana is purely a geophagous species. Seeds of earthworms can easily be transported if they are properly packed in vials with water soaked filter paper. The seeds will not hatch out within 10 days from the date of their laying.