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An experiment was carried out to determine the effect of replacing dietary fish meal protein with earthworm meal protein on growth performance, whole-body composition, and hematology of butter catfish (Ompok pabda). This experiment was conducted in 15 glass aquaria (200 L) with five treatments, each having three replications. Each of the aquaria was stocked with 40 fishes (average weight 0.62 g). The fish were fed with iso-nitrogenous diets having 35% protein (21% protein from fish meal and/or earthworm meal) twice a day up to satiation with the experimental diets, where fish meal protein was replaced by earthworm meal protein at 0% (control), 25%, 50%, 75%, and 100% in the treatments E0, E25, E50, E75, and E100, respectively. At the end of the 8-week rearing period, the best growth performances including weight gain (5.23 ± 0.14 g), percent weight gain (844.15 ± 6.38%), and specific growth rate (4.00 ± 0.11% day−1), and best feed utilization parameters, viz., feed conversion ratio (1.57 ± 0.03) and protein efficiency ratio (2.87±0.04), were found in treatment E75, where 75% of fish meal protein in the diet was replaced with earthworm meal protein. The hematological parameters showed no abnormality due to supplementation of earthworm meal in the diets. At the end of the experiment, whole-body carcass composition, viz., protein, lipid, and ash contents (15.93 ± 0.19%, 7.22 ± 0.60% and 2.14 ± 0.10%, respectively), of O. pabda was higher in treatment E75 compared to control (14.8 2± 0.34, 6.16 ± 0.27, 1.89 ± 0.10, respectively). The results imply that earthworm meal can be used as a protein-rich source to replace fish meal, the major protein source, in the diet of O. pabda up to 75% level without compromising growth, immunity, and body composition.

Present study deals with cocoon biology of tropical epigeic earthworm Perionyx excavatus (Perrier), Perionyx ceylanensis (Michaelsen) and Eudrilus eugeniae (Kinberg). Ultra structure observed under Scanning Electron Microscope (SEM) revealed that wall of the cocoon is porous (which helps in aeration) and the terminal part of the cocoon is softer than that of middle part which facilitates the hatching process. The size of the cocoon varies among the species and is related to the diameter and length of the clitellum. All the epigeic species under study are continuous breeder with high fecundity. Among the studied species shortest incubation period, highest fecundity and highest hatching rate were observed in P. ceylanensis. Cocoon production in these three epigeic species increases in summer and monsoon season and decreases in the winter season. Temperature is the limiting factor for cocoon production as well as incubation period of cocoon. Cocoon production was affected by temperature and body weight of the earthworm. Thus it can be considered that cocoon production in epigeic earthworm species depends on biological factor (body mass), as well as, ecological factor (temperature). Continuous breeding strategy, high fecundity, high rate of cocoon production, as well as high hatching rate, indicates greater usefulness of P. ceylanensis followed by E. eugeniae than P. excavatus in the vermiculture based biotechnology in North-East India.

Paddy is one of the most important food crops in India. In Tripura of north east India, paddy covers 78–90% of cultivable areas with hydromorphic clay-rich acidic soils. As earthworms have important role in above-ground crop production, the present study deals with the earthworm communities in the soils of wet land paddy agro-ecosystem of West Tripura (India). The study was conducted during May 2015 to August 2017. Earthworms were collected from the paddy fields by TBSF monolith (25 × 25 × 30 cm) digging and hand sorting method. Temperature, moisture, pH and organic matters were estimated from 0 to 15 cm depth soils. Biological parameters such as density, biomass, relative abundance and ecological parameters such as indices of diversity, dominance etc. were measured. A total of 7 earthworm species belonging to 4 families and 5 genera were recorded: [Almidae Glyphidrilus sp. (near to gangeticus)], Moniligastridae (Drawida assamensis, Drawida papillifer papillifer and Drawida sp.), Megascolecidae (Metaphire houlleti, Perionyx excavatus) and Glossoscolecidae (Pontoscolex corethrurus). The average density and biomass of earthworms in the paddy plantations were 163 ind. m−2 and 56 g m−2 respectively. Diversity and dominance indices of earthworms of paddy plantations were 0.46 and 0.60 respectively. Glyphidrilus sp. contributed more than 50% biomass and density of earthworm community and probably had a great role in paddy production due to enormous deposition of casts (‘cast hills’) in the rhizosphere zone of paddy plants.

Recovering the nutrients from organic solid residues is an ever demanding approach in terms of eco-friendly management. In this study, the efficiency of the earthworms, Perionyx ceylanensis and Perionyx excavatus in recycling and recovering plant nutrients from urban and agricultural biomass residues was investigated. Vermicomposting of four different types of organic biomass resources in combination with cowdung (1:1) for 50 days was conducted using the earthworms, P. ceylanensis, and P. excavatus. Physico-chemical, microbiological and maturity characteristics of the final product were analyzed. Results showed a decrease in pH, organic matter content (OMC), total organic carbon (TOC), cellulose, lignin, carbon to nitrogen (C/N) and carbon to phosphorus (C/P) ratios, and an increase in total Kjeldahl nitrogen (TKN), phosphorus (TP), potassium (TP), calcium and sodium in vermicomposts over composts (prepared without earthworms). TKN increase in vermicomposts over composts was insignificant between P. ceylanensis and P. excavatus, while it was significant for TP, TK, and total microbial population (P

Maintaining genomic stability is inevitable for organism survival and it is challenged by mutagenic agents, which include ultraviolet (UV) radiation. Whenever DNA damage occurs, it is sensed by DNA-repairing proteins and thereby performing the DNA-repair mechanism. Specifically, in response to DNA damage, H2AX is a key protein involved in initiating the DNA-repair processes. In this present study, we investigate the effect of UV-C on earthworm, Perionyx excavatus and analyzed the DNA-damage response. Briefly, we expose the worms to different doses of UV-C and find that worms are highly sensitive to UV-C. As a primary response, earthworms produce coelomic fluid followed by autotomy. However, tissue inflammation followed by death is observed when we expose worm to increased doses of UV-C. In particular, UV-C promotes damages in skin layers and on the contrary, it mediates the chloragogen and epithelial outgrowth in intestinal tissues. Furthermore, UV-C promotes DNA damages followed by upregulation of H2AX on dose-dependent manner. Our finding confirms DNA damage caused by UV-C is directly proportional to the expression of H2AX. In short, we conclude that H2AX is present in the invertebrate earthworm, which plays an evolutionarily conserved role in DNA damage event as like that in higher animals.

Background Earthworm communities are generally very sensitive to physico-chemical properties of the soil in different agro-ecosystem i.e. cultivated or non-cultivated which directly or indirectly influence the earthworm survival. The difference in physico-chemical properties of soil at different sites contributed to the formation of population patches for earthworm species. Understanding the physico-chemical properties of soil at a particular site could facilitate the prediction of earthworm species at that site. The objective of the present study was to investigate the diversity, abundance, and distribution of earthworms in cultivated and non-cultivated agroecosystems and their physico-chemical properties affecting the earthworm diversity and abundance. Results Total 10 species of earthworms i.e. Amynthas alexandri, Amynthas morrisi, Eutyphoeus incommodus, Eutyphoeus waltoni, Metaphire birmanica, Metaphire houlleti, Metaphire posthuma, Octochaetona beatrix, Perionyx excavatus, and Polypheretima elongata, were reported. Out of all the reported species, Metaphire posthuma was found to be the most abundant earthworm species in both cultivated and non-cultivated agroecosystems with the occurrence at 56.81% sites. The Shannon-Wiener index (H), Margalef species richness index (DMg) and Pielou species evenness (E) was ranged from 0 to 0.86, 0 to 0.64 and 0.78 to 1 respectively. The principal component analysis resulted in four principal components i.e. PC1, PC2, PC3 and PC4 which contributing variance (%) of 22.96, 19.37, 14.23 and 10.10 respectively. The principal component analysis also showed that physico-chemical parameters of soil such as EC, pH, TDS, texture, OC, moisture, etc. play a critical role in earthworm distribution. Conclusion The conventional farming system has a negative effect on the earthworm diversity in the soil while the physico-chemical properties of soil also have a determinant effect on the same. Earthworms abundance in the present study have significant direct relation with soil properties at a particular site and vice versa. The diversity indices also change due to the conventional farming system which directly affects the earthworm abundance.

Carbon to nitrogen (C/N) ratio influences substrate combinations and earthworm performance in vermicomposting systems. To elucidate these factor effects, a comparative evaluation of species, C/N ratio combined with feed rate, was conducted on three local earthworm species: Perionyx excavatus, Eudrilus eugeniae, and Dichogaster annae. Earthworms were stocked at similar densities and fed shredded paper (SP), cattle manure (CM), and lawn clippings (LC) combined to form C/N ratios of 28, 36, and 53. Earthworms were fed at rates of 1, 1.25, and 2 g feed (dry wt.)/g worm/day for a period of 8 weeks. Percent vermiconversion, earthworm adult and juvenile biomass, and vermicast quality were measured. Vermicast production was significantly affected by the combination of C/N ratio and feed rate and varied among species. All treatment combinations resulted in > 70% conversion, except E. eugenaie fed at the medium rate. Vermiconversion increased for P. excavatus and D. annae with increasing C/N ratio but decreased with increasing the feed rate. Vermicast EC, pH, and C/N ratio was strongly affected by species, relative to other experimental factors. D. annae showed the greatest change in biomass, which peaked at the highest feed rate and lowest C/N ratio. Average adult biomass decreased for P. excavatus with increasing feed rate, while differences were nonsignificant for E. eugenaie and D. annae. Significant increases in average juvenile biomass were only evident for D. annae in response to increasing feed rates. Feed rate had a greater influence on earthworm population dynamics and vermicast quality compared to initial feedstock C/N ratio.

The earthworm Perionyx excavatus is a species highly capable of bidirectional regeneration. Pair-rule genes are thought to have an ancestral function in arthropod segmentation. However, orthologs in annelids (i.e. Capitella teleta) do not exhibit segmental expression in the ectoderm or mesoderm. Their role in regeneration is currently unclear. Here, we report the expression profile of primary pair-rule genes (Pex-EvxA, Pex-EvxB, Pex-RuntA, Pex-RuntB, Pex-Hes1A, Pex-Hes1B, Pex-Hes4A, and Pex-Hey) found in P. excavatus using semi-quantitative reverse transcription-polymerase chain reaction. Our results indicated these genes showed variable expression during bidirectional regeneration. Six of these genes might play diverse and potentially critical roles in head and/or tail regeneration.

The aim of this study was to recycle and reuse the enormously available unutilized lignocellulosic solid organic waste resource, cashew leaf litter (CLL) admixed with various animal dungs, cowdung, sheepdung and horsedung by employing predominantly available indigenous epigeic earthworm—Perionyx excavatus (Perrier, 1872) and produce quality vermifertilizer. Four different combinations of each [(100 % dung alone, 3:1 (75 % dung + 25 % CLL), 2:2 (50 % dung + 50 % CLL) and 1:3 (25 % dung + 75 % CLL)] vermibeds were allowed for vermicomposting process under laboratory conditions. After 60 days, the worm worked vermicompost and worm unworked normal compost were harvested and characterized. The earthworm activity—growth, reproductive performance (cocoon production and hatchling number) and recovery of vermicompost was also studied. The obtained results clearly showed that vermicompost from CLL admixed with cowdung at 2:2 ratio had lower pH, organic carbon, C–N ratio, C–P ratio, lignin, cellulose, hemicellulose and phenol content, and higher nitrogen, phosphorus, potassium dehydrogenase and humic acid content than the raw substrates and worm unworked normal compost. In addition, pronounced and better earthworm activity was found in the above combination. Through vermitechnology way of producing agronomic valid vermicompost using natural waste resources like CLL and animal dungs can be used as bio-organic fertilizer. These vermiresources have vast and diversified potential for maintaining sustainable soil health, fertility, productivity, waste degradation, soil reclamation, land restoration practices and environment health.

Triphenyl phosphate (TPHP) is one of the most highly utilized organophosphorus flame retardants, and has been frequently detected in various environmental matrices, including soil. So far, limited information is known regarding the potential toxicity of TPHP to the earthworm-soil ecosystem. We investigated the metabolism of TPHP and the perturbation of the endogenous metabolome in the earthworm, Perionyx excavatus, using gas chromatography mass spectrometry (GC-MS) and liquid chromatography quadrupole time-of-flight (LC-QTOF)-based untargeted metabolomics approach after acute exposure to TPHP for one and two days through a filter paper contact test, as well as after chronic exposure for 28 days in a soil microcosm experiment. TPHP showed low bioaccumulation potential in the earthworm-soil ecosystem at concentrations of 10 mg/kg and 50 mg/kg. Identified phase I metabolites include diphenyl phosphate, mono-hydroxylated and di-hydroxylated TPHP. Two groups of phase II metabolites, thiol conjugates (including mercaptolactic acid, cysteine, cysteinylglycine, and mercaptoethanol conjugates) and glucoside conjugates (including glucoside, glucoside-phosphate, and C14H19O10P conjugates), were putatively identified. Only acute TPHP exposure caused significant perturbations of the endogenous metabolome in earthworms, featuring fluctuations in amino acids, glucose, inosine and phospholipids. These results reveal novel phase II metabolism and toxicity of TPHP in P. excavatus.

Present study revealed the presence of 16 earthworm species belonging to 11 genera and four families viz. Megascolecidae (Amynthus alexandri, Metaphire houlleti, Lampito mauritii, Kanchuria sp1, Perionyx excavatus), Octochaetidae (Eutyphoeus gigas, Eutyphoeus comillahnus, Eutyphoeus orientalis, Octochaetona beatrix, Dichogaster bolaui, Lennogaster chittagongensis, Lennogaster yeicus), Moniligastridae (Drawida papillifer papillifer, Drawida assamensis, Drawida nepalensis) and Glossoscolecidae (Pontoscolex corethrurus) in the soils of five bamboo species [Bambusa balcooa (Sil Barak), Melocanna baccifera (Muli), Bambusa polumorpha (Bari), Bambus cacharensis (Bom) and Bambus bambus (Katabarak)] of West-Tripura. While four earthworm species viz. Metaphire houlleti, Drawida assamensis, Drawida papillifer papillifer and Pontoscolex corethrurus were common to all species of bamboo plantations, the rest showed restricted distribution. Among the earthworm species 4 were exotic (Amynthus alexandri, Metaphire houlleti, Dichogaster bolaui and Pontoscolex corethrurus) and the others were native to the Indian sub-continent. In general, earthworms under the bamboo plantations occurred within temperature range of 21.6 °C–28.0 °C, pH 4.0–7.0, organic matter 0.56–5.99 %, moisture 9.6–31.7 %, water holding capacity 14.6–43.9 % and bulk density 0.7–1.8 g cm−3. The average density and biomass of the earthworms in the studied places were 108 ind m−2 and 44 g m−2 respectively. Earthworm diversity, dominance and evenness indices showed the values 1.00, 0.47 and 0.70 respectively. Earthworm density and biomass showed a negative correlation with temperature whereas those had a strong positive correlation with pH, moisture and organic matter of the soils.

The aim of this study was to investigate the biochemical responses in three earthworm species, Eudrilus eugeniae, Perionyx ceylanensis and Perionyx excavatus induced by exposure to pesticide (carbaryl) and metal (lead) in soil. Earthworms were exposed to increasing concentrations of carbaryl (12, 25 and 50 mg kg −1) and Pb (75, 150 and 300 mg kg −1) in the soil for different periods of time and the biochemical changes were determined. The protein content was slightly increased in E. eugeniae, P. ceylanensis when exposed to the lower concentration of Pb (75 mg kg−1). But decreased protein content was observed in P. excavatus at the higher concentration of carbaryl (50 mg kg−1), and with exposure to 300 mg kg−1 Pb in P. ceylanensis. The changes in the levels of antioxidant enzymes glutathione-S-transferase (GST), glutathione peroxidase (GPx), reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) were used as functional biomarkers to determine the effect of pesticides and metals on earthworms. Among these, GST exhibited more sensitive response to both carbaryl and Pb as compared to the control. Other antioxidant enzymes showed little variation at the time of exposure. The results of our study suggested that both carbaryl and Pb induced the production of Reactive oxygen species (ROS) by causing oxidative damage to cells. Due to an adaptive response of earthworms in contaminated soils, they could be used as significant biomarkers to asses the toxicity in the environment of the soil ecosystem. This is the first report on the comparative study of antioxidant enzyme activities in three earthworm species under normal and stress induced conditions.

The aim of the study was to examine safe reuse and recycling of organic waste digestate obtained from a biogas plant (5 % total solid) with enhanced nutrient value through vermitechnology. Two indigenous epigeic earthworm species Perionyx excavates and Perionyx sansibaricus were tried individually for this purpose. The results clearly show a significant increase in pH values from 6.5–7.4, electrical conductivity (21.3–21.7 %), total N (84.5–94.6 %), total P (35.9–47.1 %), total K (49.8–52.6 %), Ca (41.9–41.9 %) and a significant decrease in total organic C (17.1–22.4 %), C/N ratio (7.2–6.9), C/P ratio (20.3–20.6), COD (51.9–55.7 %), BOD (85.5–91.2 %). Similarly, indicator organisms (fecal coliforms and fecal streptococci) showed decrement at the end of the composting period (60 days). Fecal Coliforms reduce to nil, while in fecal streptococci a 6 log reduction was observed. Oxygen uptake rate dropped to 67.4–70 % for vermireactors. Overall, the aforementioned findings highlighted that the indigenous earthworm species could enhance the nutrient value of the anaerobic digestate, which could be utilized as an efficient soil conditioner.

Present studies on the community characteristics of earthworms revealed the occurrence of 11 species of earthworms in the pineapple (Ananus comosus) and 14 species in the mixed fruit plantations of west Tripura (India). While 9 species of earthworms namely Drawida assamensis, Drawida papillifer papillifer, Drawida nepalensis, Kanchuria sp., Metaphire houlleti, Eutyphoeus gigas, Eutyphoeus scutarius, Eutyphoeus comillahnus and Pontoscolex corethrurus are of common occurrence to both the pineapple and the mixed fruit plantations, two and five earthworm species namely Kanchuria sumerianus, Eutyphoeus sp. and Metaphire posthuma, Perionyx excavatus, Lampito mauritii, Amynthus alexandri, Eutyphoeus gammiei are restricted to the pineapple and the mixed fruit plantations respectively. Earthworms were found mostly within 15 cm depth of soils having temperature 25–25.8 °C, moisture 18.8–22.4 %, water holding capacity 26–31.7 % and organic matter content 2.4–4.0 %. Mean earthworm densities (158 ind. m−2) was significantly higher (p < 0.01, t = 9.67) and biomass (36.67 g m−2) significantly lower (p < 0.01, t = −5.98) in the pineapple plantation than the mixed fruit plantation (density 93 ind. m−2, biomass 56 g m−2). High density value of earthworms in pineapple plantation is linked with dominance of D. assamensis and high biomass value in mixed fruit plantation was due to the higher relative abundance of larger species like E. gigas, E. scutarius, E. comillahnus and E. gammiei. Compared to the mixed fruit plantation, significantly (p < 0.05) higher index of dominance, lower index of diversity, species richness index and species evenness were recorded in the pineapple plantation.

Epigeic earthworms (Oligochaeta) have been appeared as key organisms to convert organic waste resources into value-added products, i.e., vermicompost and worm biomass. The assessment of reproduction potential of composting earthworm may be beneficial for large-scale earthworm production. Although, the waste minimizing potential of Perionyx excavatus and Perionyx sansibaricus is well proved, but little information is available about their fecundity rate. In this study, the efforts have been made to explore the growth and reproduction biology of P. excavatus and P. sansibaricus, using cattle waste solid as culture substrate, under laboratory conditions. Earthworms were weighed weekly and number of cocoons produced per week assessed. Biomass productions, fecundity, maturation, natality all were significantly different between P. excavatus and P. sansibaricus. The highest mean individual biomass was 767.7 ± 18.4 mg and 612.6 ± 20.6 mg, respectively in P. sansibaricus and P. excavatus. However, the highest cocoon numbers occurred in P. excavatus (492.3 ± 13.6), significantly higher than P. sansibaricus (269.6 ± 17.1). Fecundity was slightly different in both species: 1.38 ± 0.77 cocoons adult worm−1 week−1 (P. excavatus) and 1.58 ± 0.74 cocoons adult worm−1 week−1 (P. sansibaricus). The hatchling success rate (%) was highest in P. excavatus. Overall natality (juveniles adult−1 week−1) was highest in P. sansibaricus (1.52) than P. excavatus (1.26), which suggests that P. sansibaricus may be a better candidate for rapid propagation of earthworms in cattle waste solid.

The composting potential of two epigeic earthworms (P. excavatus and P. sansibaricus) was studied in 2002 to breakdown the domestic waste under laboratory conditions. The experimental container with P. sansibaricus showed maximum mineralization and decomposition rate than that of P. excavatus. Except for exchangeable K (it was higher (P = 0.004) in a container with P. excavatus), the domestic waste processed by P. sansibaricus showed about 6% more total nitrogen (P = 0.002) and about 7% more available P (P = 0.269) at the end than by P. excavatus. As compared with the initial level organic C content as well as C:N ratio showed a considerable reduction that was noted higher in substrate with P. sansibaricus than those by P. excavatus (organic C, t-test: P = 0.870; C:N ratio, t-test: P = 0.002). The growth (biomass increase) and reproduction parameters such as mean individual live weight, maximum individual growth rate (mg wt./worm/day), number of cocoons and reproduction rate (cocoon/worm/day) were higher in bedding with P. sansibaricus. The maximum earthworm mortality was in vermibed having P. sansibaricus (∼50% higher than by P. excavatus) (t-test: P = 0.423), since both species did not show a drastic difference in waste mineralization rate, but comparatively, P. excavatus exhibited better growth and reproduction performance, which further support the suitability of the species for large scale vermiculture operations.

The practice of vermiculture is at least a century old but it is now being revived worldwide with diverse ecological objectives such as waste management, soil detoxification and regeneration and sustainable agriculture. Earthworms act in the soil as aerators, grinders, crushers, chemical degraders and biological stimulators. They secrete enzymes, proteases, lipases, amylases, cellulases and chitinases which bring about rapid biochemical conversion of the cellulosic and the proteinaceous materials in the variety of organic wastes which originate from homes, gardens, dairies and farms. The process is odour free because earthworms release coelomic fluids in the decaying waste biomass which has anti-bacterial properties which kills pathogens. The species used in India were Indian blue (Perionyx excavatus), African night crawler (Eudrilus euginae) and the Tiger worm (Elsinia foetida). E. foetida was used in Australia. E. euginae was found to have higher feeding, growth and biodegradation capacity compared to other two species.

One-week-old juveniles of Perionyx excavatus were cultured in urine-free cow manure for 16 weeks in three different seasons to find out the influence of environmental factors on growth and reproduction. The biomass of worms increased gradually until the 16th week in all seasons. There was no significant (F=2.51) variation in biomass between the three seasons; however, the growth rate varied significantly (F=50.49, P

The life cycle of Perionyx excavatus has been studied and the potential of this epigeic earthworm species for breaking down and processing organic wastes is well known. Understanding of its optimal environmental requirements is required in order to optimize and accelerate the vermicomposting process. The rates of growth and reproduction of P. excavatus, on a variety of organic wastes, were evaluated in these experiments. The time of maturation and the rates of growth of this species, under various population density pressures and temperatures between 15 °C and 30 °C, were also assessed. Increasing temperatures up to 30 °C accelerated the growth of earthworms and lessened the time to sexual maturity. However, the highest rates of reproduction occurred at 25 °C both in cattle solids and sewage sludge. The mean time to egg hatching decreased and the degree of hatching success increased with increasing temperature. Earthworms grew at similar rates in cattle solids, pig solids and aerobically digested sewage sludge, but the earthworms did not grow well in horse solids and grew only poorly in turkey wastes. The maximum individual growth rates as a function of earthworm population and the maximum earthworm weights as a function of time with a constant food supply at four different temperatures were assessed.

A ParaHox gene cluster is composed of three genes (Gsx, Xlox, and Cdx). It has been proposed that all three ParaHox genes were present in the last common ancestor to the lophotrochozoan protostomes and the deuterostomes and that gene loss event has occurred in the ecdysozoan lineage. In this paper, we report the existence of all three ParaHox genes in Perionyx excavatus, a clitellate annelid. Although orthologs of each of the three ParaHox genes were previously discovered from other lopotrochozoan taxa, this study constitutes the first reported isolation of all three ParaHox genes in the same clitellate species.

An outdoor study was undertaken using polyethylene containers to assess the suitability of different organic residues, soybean straw (Glycine max L. Merril.), wheat straw (Triticum aestivum L.), maize stover (Zea mays L.), chickpea straw (citer arietinum L.) and city garbage, as food for the tropical epigeic earthwormPerionyx excavatus, and to assess the influence of this earthworm on the decomposition of these materials. Maize stover was found to be the most suitable of the food materials used. Population growth ofP. excavatus was enhanced by addition of these organic materials in the temperature range 24°-30°C, while the population was adversely affected above 30°C in a vermiculture system. Addition of earthworms accelerated the breakdown of residues, which ultimately resulted in a lowering of the C:N ratio, water-soluble carbon and carbohydrates, and increased ash percentage and cation exchange capacity compared with their respective controls.

The casts of earthworms contain greater amounts of extractable inorganic phosphate than underlying soils. Casts contain higher phosphatase activity than that occurs in undigested soil, which increases the inorganic phosphorus released by mineralization. Of the 4 species compared,Perionyx excavatus showed a higher faecal phosphatase activity. Composition of casts vary with species. pH increases and nutrients accumulate in worm-activated soils. Based on the data on surface cast production, it is estimated that grasslands around Bangalore show a phosphorus turnover of about 55 kg ha−1 y−1, and the woodlands, 38 kg ha−1 y−1.

The biology of the oriental vermicomposting species, Perionyx excavatus, is poorly understood. Quantitative observations were made at 25°C in urine free cattle manure in order to study the growth of this species. The rate of maturation and cocoon production were studied under conditions of favourable moisture and nutrition over a period of 250 days. The results obtained showed that while P. excavatus grows relatively slowly compared to other vermicomposting species, it attains sexual maturity much earlier and maintains a relatively high cocoon production rate. The study revealed that copulation is not a prerequisite for production of viable cocoons, indicating that P. excavatus may be parthenogenetic and possibly capable of alternating between modes of reproduction.