Philosamia Ricini Research Articles

Incidence of superparasitism in the egg parasitoid, Ooencyrtus kuvanae Howard (Hymenoptera: Encyrtidae)

ABSTRACTThe encyrtid Ooencyrtus kuvanae is a solitary parasitoid of the gypsy moth, Lymantria dispar L. (Lepidoptera-Lymantridae) that is used in biological control programmes and whose mass rearing is influenced by superparasitism. The purpose of this study was to investigate the effect of the self-superparasitism of O. kuvanae at different host densities (5, 10, 15 and 20), female ages (3 and 5 days) and durations of exposure (1 and 5 days) under various laboratory conditions (25°C ± 1°C, RH 60 ± 5% and a 16:8 h light:dark photoperiod) as well as in a new laboratory host, Philosamia ricini (Danovan) (Lepidoptera: Saturniidae) of O. kuvanae. In this study, we determined the rate of egg superparasitism and adult emergence and recorded development time, longevity and body weight. Superparasitism increased with female age and the duration of exposure to parasitoids when females had access to five host eggs. Superparasitism increased the number of parasitoid offspring, but it resulted in male-biased (56.90%) progeny. Furthermore, superparasitism caused deleterious effects to the fitness of the progeny by prolonging the developmental process, and decreasing longevity. For example, we found that when four adults can emerge from one superparasitised host egg, the body size of the parasitoid offspring decreases significantly. Hence, superparasitism should be avoided when mass rearing O. kuvanae.

Antioxidant potential of mulberry and non-mulberry silk sericin and its implications in biomedicine

Sericin, a principal constituent of silk, is widely used in various biomedical applications. In addition, conferring protection against free radicals and oxidative damage add more value to its therapeutic potential. However, the antioxidant (AO) properties of silk sericin (SS) remains contingent on extraction procedures. In the present study, we have evaluated the effect of different extraction methods (conventional, autoclaving, urea, alkali and acid-degradation) on AO properties of SS from three Indian silk varieties [Antheraea assamensis (AA), Philosamia ricini (PR) and Bombyx mori (BM)]. The physico-chemical characterization studies revealed that the molecular weight of SS isolates of each method ranged from 10 to 220kDa along with varied protein structural biochemistry. SS extracts using urea-degradation (BM, PR and AA), conventional method and alkali-degradation (BM) displayed high percentage of β-sheets, random coils and turns. Acid-degraded SS (PR, followed by AA and BM) showed the highest total flavonoid content while conventional method (PR), autoclaving (AA) and alkali-degradation (BM) displayed lowest flavonoid levels. Interestingly, SS extracted by autoclaving (BM and AA), acid-degradation (PR), conventional and alkali-degradation (BM, AA and PR) methods exhibited 50% reduction of 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical. Moreover, the efficacy of antioxidant potential of SS extracted by different methods was found to be in the order of “alkali>autoclaving>conventional” as demonstrated in L929 cells. Correspondingly, the anti-lipid peroxidation activity of SS extracted by alkali method (AA, BM and PR) further confirmed better AO properties amid others. Thus, the present study demonstrates that the extraction methods may significantly affect AO activity of SS which might be of importance for potential cosmetic applications.

Cypermethrin Formulation (Ustad-10 EC) Induces Genotoxicity via Apoptosis, Affects Nutritional Physiology, and Modulates Immune Response in Silkworm Philosamia ricini (Lepidoptera: Saturniidae).

Cypermethrin is a pyrethroid insecticide with high insecticidal activity, low mammalian toxicity, and biodegradability. The present study aimed to determine the acute toxicity and evaluate the secondary toxic effects of a commercial formulation of cypermethrin on silkworm Philosamia ricini Hutt of Northeast India. The potential genotoxicity of cypermethrin on silkworm hemocyte was examined by comet assay, caspase activation, and annexin V affinity assay. Alteration in nutritional physiology and histoarchitecture of the gut region was evaluated. Additionally, immunotoxicological effect of cypermethrin was studied by phenoloxidase (PO), lysozyme assay, and abundance of circulating hemocytes. The LC50 value at 24-, 48-, 72-, and 96-h exposure period was recorded as 185.96, 105.34, 72.42, and 58.41 µg/liter, respectively. Approximately sevenfold increase in mean comet tail length was observed at 24 h posttreatment with sublethal concentrations of cypermethrin. Cypermethrin also induced apoptosis and activated caspase reaction in silkworm hemocytes. Moreover, a significant decrease in digestive enzyme activity was observed at higher concentrations of cypermethrin. In cypermethrin-exposed groups, alteration in histoarchitecture was also observed in the form of ruptured microvilli and thin, deformed, fused mucous layer. The PO enzyme and lysozyme enzyme activity was also altered with sublethal concentration of cypermethrin. Total hemocyte count was reduced to 10587.10, 10052.30, 9234.30, and 8842.60 per mm3 with 10, 20, 30, and 40 µg/liter, respectively. The results offer new insights into the negative consequences of very low concentrations of cypermethrin formulations on nonmulberry silkworm of Northeast India.

A new substitute host and its effects on some biological properties of Ooencyrtus kuvanae.

Lymantia dispar (L.) (Lepidoptera: Lymantriidae), commonly known as the gypsy moth, is a serious forest pest, and beneficial insects are particularly important for reducing its population numbers. Ooencyrtus kuvanae (Howard) (Hymenoptera: Encyrtidae) is an arrhenotokous, solitary egg parasitoid of L. dispar. In this study, we evaluated a new substitute host, Philosamia ricini (Danovan) (Lepidoptera: Saturniidae) for O. kuvanae. We investigated some of the biological effects of O. kuvanae on P. ricini eggs. In this context, the importance of the age of the female parasitoid (1, 3 or 5 days old), host age (1-2 and 3-4 days old) and host number (40, 60 and 80 host eggs) were examined under laboratory conditions (25 ± 1 °C, 65 ± 5% relative humidity and a 16 : 8 h photoperiod [light : dark]). The highest rate of offspring production (89.90%) occurred with 40 (1-2-day-old) host eggs and 5-day-old females. The mean developmental period ranged from 16.5 ± 0.08 days to 18.7 ± 0.08 days. The mean lifespan of the parasitoid was 51.10 ± 1.1 (n = 60) days with bio-honey and 3.92 ± 0.14 (n = 60) days without food. The mean fecundity was 68.88 ± 3.22 offspring/female. Peak adult emergence occurred between 2 and 9 days. The mean oviposition and mean post-oviposition periods of the female parasitoid were 22.76 ± 1.37 days and 13.64 ± 1.40 days, respectively. O. kuvanae was reared for more than ten generations on the eggs of P. ricini. Based on our findings, P. ricini can be used to rear O. kuvanae for the biological control of L. dispar.

Time Course Studies on Impact of Low Temperature Exposure on the Levels of Protein and Enzymes in Fifth Instar Larvae of Eri Silkworm, Philosamia ricini (Lepidoptera: satuniidae)

Lactate dehydrogenase (LDH; EC 1.1.1.27) and malate dehydrogenase (MDH; EC 1.1.1.37) are the enzymes involved in energy metabolism of Eri silkworm, Philosamia ricini. However, no previous study has been reported about effect of low temperature exposure on their levels in different tissues of Eri silkworm. The present study was aimed to the time-course effects of low temperature (~10°C) exposure of 5th instar P. ricini on the levels of protein and energy metabolism enzymes of three major tissues (haemolymph, silk gland and fat body). The Eri silkworm larvae, reared on fresh leaves of castor-oil-plant (Ricinus communis), were divided into 4 groups: a control group reared at 25 ± 2°C along with three experimental groups reared at 10 ± 1°C containing 50 larvae in each, for varying durations (2, 4 and 7 days). The cell free extract was prepared by centrifuging the tissue homogenate at 9000 g and used for biochemical estimations (total protein content, lactate dehydrogenase and malate dehydrogenase activities). For isozyme analysis, another set of homogenates (20% w/v) was prepared in buffer (0.2 M Tris HCl, pH 7.0) containing 0.2 M sucrose and 10 mM EDTA, and analyzed by native-PAGE followed by activity staining. The activities of lactate dehydrogenase and malate dehydrogenase showed significant decrease in haemolymph, whereas in fat bodies both enzymes showed increased activity. In silk gland, Lactate dehydrogenase activity decreased uniformly, whereas malate dehydrogenase activity increased at all exposure durations. The isozyme analysis revealed significant perturbations in their expression profiles. The low temperature exposure resulted into accumulation of protein content in haemolymph and depletion in silk gland and fat body tissues. Fat bodies emerged as the main energy producing organ under this condition. Lactate dehydrogenase and malate dehydrogenase displayed presence of only one isozyme in all the tissues tested. The isozyme behaviour of lactate dehydrogenase and malate dehydrogenase towards low temperature varied in different tissues. These results suggested that alterations in expression and functions of these enzymes might be associated to the acclimation of larvae at low temperature.

Opportunities and Challenges in Exploring Indian Non-Mulberry Silk for Biomedical Applications

Owing to innate desirable features like biocompatibility, mechanical robustness, tunable biodegradability and amenability to multiple formatting, silk (christened as the ‘queen of textile’) has carved a unique niche in the realm of regenerative medicine. Silkworms, being the major source of silk are generally classified as mulberry and nonmulberry types depending on their feeding habit. Over the years, numerous patents and publications on mulberry based silk for various biomedical applications have been added to the scientific repository. In sharp contrast to this, the (immense) potential of the nonmulberry silk for biotechnological applications has been realised quite late and as such only a very few scientific documentations exists. In this article, we have presented the prospects and the recent endeavors to exploit nonmulberry silk (encompassing both fibroin and sericin) extracted from Antheraea mylitta ( tasar ) , Antheraea assamensis ( muga ) , Philosamia ricini ( eri ) etc. for fabrication of different formats of biomaterials (including, scaffolds, films, hydrogels, nanoparticles etc.) in applications like 3D tissue engineering (bone, skin etc.) and drug delivery, amongst others. The focus of the article is to highlight the prospective avenues of exploring nonmulberry silk in biomedical domain, reflected through some of our select research works along with few recent endeavors of our colleagues. The compilation is presented with the impetus that siphoning of non mulberry silk from the textile industry to the domain of biomaterial science can provide a fillip to the otherwise dwindling seri-industries of pockets like North East India.

The effect of different photoperiod on the weight of different larval Instars of Eri Silkworm (Philosamia ricini) L (Saturniidae: Lepidoptera)

The effects of different photoperiod on the weight of different larval Instars of Eri Silkworm (Philosamia ricini) in gram were studied. The experiments were performed in Zoology Department of Govt. P.G. M.V.M. Ujjain. The disease free laying (DFL’S) were collected from Govt. Sericulture Dept. Indore. Worms were reared under hygienic laboratory condition. The optimum temperature 25±2ºC and relative humidity 75±5% were maintained during complete experiment. The IInstar larvae attained maximum weightat 12hr. light and 12hr. dark. The II, III and IV Instars attained maximum weight in complete darkness and lowest weight in complete light.The V Instarlarvae attained maximum weight at 8hr. light and 16hr. dark.

Larval Exposure to Chlorpyrifos Affects Nutritional Physiology and Induces Genotoxicity in Silkworm Philosamia ricini (Lepidoptera: Saturniidae).

Chlorpyrifos is a most widely used organophosphate insecticide because of its cost effectiveness and degradable nature. However, this pesticide enters and contaminates the environment either by direct application, spray drifts or crop run off and shows adverse effect on the non-targeted organisms. Philosamia ricini (eri silkworm), one of the most exploited, domesticated and commercialized non mulberry silkworm is known for mass production of eri silk. The silkworm larvae get exposed to pesticide residues on the leaves of food plants. The present study investigates the effect of commercial formulation of chlorpyrifos (Pyrifos-20 EC) on eri silkworm. Initially the LC50 value of chlorpyrifos was determined at 24–96 h and further experiments were carried out with sub lethal concentrations of the chlorpyrifos after 24 h of exposure period. The potential toxicity of chlorpyrifos was evaluated as a fuction of metabolism and nutritional physiology in 3rd, 4th, and 5th instar larvae. Alteration in histoarchitecture of 5th instar eri silkworm gut exposed to sub lethal concentration of chlorpyrifos formulation was also studied. Chlorpyrifos induced genotoxicity in silkworm hemocytes was also investigated by single cell gel electrophoresis, micronuclei assay, and apoptosis assay. Herein, LC50 values of chlorpyrifos were calculated as 3.83, 3.35, 2.68, and 2.35 mg/L at 24, 48, 72, and 96h respectively. A significant decrease in trehalose activity along with digestive enzyme activity was observed in chlorpyrifos affected groups (P < 0.05). Further, genotoxicity study revealed higher tail percentage, tail length and tail moment of the damage DNA in chlorpyrifos exposed groups (P < 0.001). Moreover, at 2.0 mg/L concentration, ~10 fold increases in tail length was observed as compared to the control. Results showed activation of caspase activity following 24 h chlorpyrifos exposure (1.5 and 2.0 mg/L) in a dose-dependent manner. Moreover, in control group less number of apoptotic cells was detected, however in both chlorpyrifos exposed groups' numbers of apoptotic cells were statistically higher (P < 0.001). Taken together, this study provides evidence that chlorpyrifos pollution might have adverse effect on overall nutritional physiology and genotoxicity of eri silkworm that could lead to reduced survivability of this economically beneficial insect.

Role of non-mulberry silk fibroin in deposition and regulation of extracellular matrix towards accelerated wound healing

A facile fabrication of a ready-to-use bioactive wound dressing capable of concomitantly accelerating the healing process as well as deposition of the extracellular matrix (ECM) to circumvent further scarring complicacies has become a focal point of research. In this backdrop, our present work is based on non-mulberry silk fibroin (NMSF) electrospun antibiotic loaded semi-occlusive mats, mimicking the ECM of skin in terms of morphology, topology, microporous structure and mechanical stiffness. Regulation of ECM deposition and isotropic orientation evinced the potential of the mat as an instructive platform for skin regeneration. The unique peptide motifs of NMSF assisted the augmented recruitment of fibroblast, keratinocytes and endothelial cells leading to accelerated wound healing. Early progression of mature granulation, faster re-epithelialization and angiogenesis in the wounds in in vivo rabbit model forwarded the blended nanofibrous mats of NMSF and PVA ferrying EGF, apt for scarless healing.

Silk-silk blend materials

Silk fibroin materials can be used as various kinds of biomedical materials. Here, we report a comparative study of silk-silk blend materials using thermal analysis and infrared spectroscopy. Four groups of silk-silk blend films were fabricated from aqueous solutions by blending Chinese Bombyx mori (Mori) with Indian Antheraea mylitta (Tussah) silk fibroin (Mori-Tussah), Mori with Antheraea assama (Muga) silk fibroin (Mori-Muga), Mori with Philosamia ricini (Eri) silk fibroin (Mori-Eri), and Mori with Thailand mulberry (Thai) silk fibroin (Mori-Thai), respectively. These silk-silk blend systems exploit the beneficial material properties of both silks. Glass transition temperatures (T g), heat capacity increments at T g, and degradation temperatures (T d) of these water-based silk-silk blend films were measured by differential scanning calorimetry (DSC) and temperature-modulated DSC (TMDSC). It was found that those silk-silk film systems were well-blended without macrophase separation. And glass transition temperatures and degradation temperatures of those silk-silk blend films can be controlled by changing the mass ratio of different silks in the blend system. Fourier transform infrared spectrometer (FTIR) was used to characterize secondary structures of silk-silk blends. The contents of alpha-helix and random coils are tunable through changing the contents of Tussah, Muga, Eri, or Thai silk in the blend system. The study demonstrates that Mori silk are fully miscible with Tussah, Muga, Eri, and Thai silk at different mass ratios, and the features of Mori silk combined with the attributes of Tussah, Muga, Eri, and Thai silk offer a useful suite of materials for a variety of applications in the future.

Supplementary effect of yeast (Saccharomyces Cerevisiae) on rearing performance of Eri Silkworm (Philosamia Ricini) in respect of some larval parameter

Silkworm need higher protein & probiotic in their diet to help its body repair cell & to make fiber exclusively at V instar. Nutrition of silkworm is sole factor which at most individually quality and quantity of silk (Laskar and Datta, 2000). Hence in the present investigation an attempt is made to study the impact fortification of castor leaf with certain food probiotic microorganism Yeast Saccharomyces cerevisiae on some larval weight & larval length of Eri silkworm Philosamia ricini. Data is collected and subjected to the statical analysis. The results indicate that there is a better larval weight and larval length when yeast (probiotic) were used. Silkworm were fed 3 different doses of yeast (Saccharomyces cerevisiae) along with castor leaf (100ppm, 200ppm, 300ppm foliar spray) and one control at Once a day , Twice a day and Trice a day.

Mimicking Form and Function of Native Small Diameter Vascular Conduits Using Mulberry and Non-mulberry Patterned Silk Films.

Autologous graft replacement as a strategy to treat diseased peripheral small diameter (≤6 mm) blood vessel is often challenged by prior vein harvesting. To address this issue, we fabricated native-tissue mimicking multilayered small diameter vascular graft (SDVG) using mulberry (Bombyx mori) and Indian endemic non-mulberry (Antheraea assama and Philosamia ricini) silk. Patterned silk films were fabricated on microgrooved PDMS mold, casted by soft lithography. The biodegradable patterned film templates with aligned cell sheets were rolled onto an inert mandrel to mimic vascular conduit. The hemocompatible and mechanically strong non-mulberry films with RGD motif supported ∼1.2 folds greater proliferation of vascular cells with aligned anchorage. Elicitation of minimal immune response on subcutaneous implantation of the films in mice was complemented by ∼45% lower TNF α secretion by in vitro macrophage culture post 7 days. Pattern-induced alignment favored the functional contractile phenotype of smooth muscle cells (SMCs), expressing the signature markers-calponin, α-smooth muscle actin (α-SMA), and smooth muscle myosin heavy chain (SM-MHC). Endothelial cells (ECs) exhibited a typical punctuated pattern of von Willebrand factor (vWF). Deposition of collagen and elastin by the SMCs substantiated the aptness of the graft with desired biomechanical attributes. Furthermore, the burst strength of the fabricated conduit was in the range of ∼915-1260 mmHg, a prerequisite to withstand physiological pressure. This novel fabrication approach may eliminate the need of maturation in a pulsatile bioreactor for obtaining functional cellular phenotype. This work is thereby an attestation to the immense prospects of exploring non-mulberry silk for bioengineering a multilayered vascular conduit similar to a native vessel in "form and function", befitting for in vivo transplantation.

Differential Expression of Middle Silk Gland Proteins Caused by Cold Stress in Philosamia ricini

This study reports differentially expressed proteins in the middle silkglands of normal and cold stress treated 5th instar Philosamia ricini larvae by using high resolution two-dimensional polyacrylamide gel electrophoresis. About 300 protein spots were resolved in both type of the larvae. Most of the proteins were shown to be distributed in the area from 20 to 70 kDa ranging between pH 4 and 8. Six proteins showed considerably decreased expression in cold stress treated samples. Three proteins displayed increased level of expression after cold stress treatment, while two other proteins were expressed exclusively in cold stress treated silkgland tissues.

Tendency and consequences of superparasitism for the parasitoid Ooencyrtus pityocampae (Hymenoptera: Encyrtidae) in parasitizing a new laboratory host, Philosamia ricini (Lepidoptera: Saturniidae)

The tendency for self-superparasitism and it's effects on the quality of the parasitoid Ooencyrtus pityocampae (Mercet) (Hymenoptera: Encyrtidae) in parasitizing a new laboratory host, Philosamia ricini (Danovan) (Lepidoptera: Saturniidae), were investigated. In this study, female parasitoids of various ages (1-, 3- and 5-day-old) were tested individually. Parasitoids were provided with 1-day-old P. ricini eggs at ratios of 5, 10, 20, 30 and 40 host eggs per wasp. The tendency to superparasitize was dependent on the female's age and host density. Five-day-old females showed a strong tendency to superparasitize at low host densities. The development time of wasps in superparasitized eggs was longer than that of wasps in singly parasitized eggs. The size and longevity of adult parasitoids decreased significantly with superparasitism. This work contributes to the development of an efficient mass rearing and laboratory rearing of the parasitoid O. pityocampae using a new host.

Effect of Spirulina (Nutritional supplement) on rearing performance of Eri Silkworm (Philosamia ricini) in respect of some larval parameter

Spirulina is a blue-green microalgae. It contains 18 amino acids and vital vitamins like Biotin, Tocopherol, Thiamine, Riboflavin, Niacin, Folic acid, Pyrodozoic acid, Beta-carotene and Vitamin B12 etc. These nutrients are very easy to digest Protein (biliprotein) &amp; Carbohydrates. Other different minerals and trace minerals, Beta-carotene, Chlorophyll, GLA Omega-3 fatty acid are also found in Spirulina. For this study we have conducted the experiments to know the effect of Spirulina (with different Concentration &amp;dosages) on the rearing performance of Eri-silkworm Philosamia ricini.We have grouped the worms along with their control and then the experimental groups were treated with the different dosages of Spirulina specially to find the effect on the larval and cocoon parameter (Larval length, Larval weight). Then the collected datas were subjected to statistical analysis .All the results were found significant.

Milled non-mulberry silk fibroin microparticles as biomaterial for biomedical applications

Silk fibroin has been widely employed in various forms as biomaterials for biomedical applications due to its superb biocompatibility and tunable degradation and mechanical properties. Herein, silk fibroin microparticles of non-mulberry silkworm species (Antheraea assamensis, Antheraea mylitta and Philosamia ricini) were fabricated via a top-down approach using a combination of wet-milling and spray drying techniques. Microparticles of mulberry silkworm (Bombyx mori) were also utilized for comparative studies. The fabricated microparticles were physico-chemically characterized for size, stability, morphology, chemical composition and thermal properties. The silk fibroin microparticles of all species were porous (∼5μm in size) and showed nearly spherical morphology with rough surface as revealed from dynamic light scattering and microscopic studies. Non-mulberry silk microparticles maintained the typical silk-II structure with β-sheet secondary conformation with higher thermal stability. Additionally, non-mulberry silk fibroin microparticles supported enhanced cell adhesion, spreading and viability of mouse fibroblasts than mulberry silk fibroin microparticles (p<0.001) as evidenced from fluorescence microscopy and cytotoxicity studies. Furthermore, in vitro drug release from the microparticles showed a significantly sustained release over 3 weeks. Taken together, this study demonstrates promising attributes of non-mulberry silk fibroin microparticles as a potential drug delivery vehicle/micro carrier for diverse biomedical applications.

Comparative studies of regenerated water-based Mori, Thai, Eri, Muga and Tussah silk fibroin films

Silk materials from different silkworm species can be utilized in various medical and material applications. In this study, five types of silk proteins: Indian Antheraea mylitta (Tussah), Philosamia ricini (Eri), Antheraea assamensis (Muga), Thailand and Chinese Bombyx mori mulberry (Thai, Mori) were successfully regenerated in the aqueous solution and were fabricated into films. Differential scanning calorimetry (DSC) and temperature-modulated DSC were used to identify glass transition temperatures (Tg), heat capacity increments at Tg and degradation temperatures of these silk films. Besides this, the bound water contents and the thermal degradation mechanisms of different silk systems were quantified using thermogravimetric analysis. In addition, Fourier transform infrared spectrometer was also utilized to investigate the structural differences of these silk films. Compared with the mulberry silk films, wild silk films showed higher thermal stabilities, and variable degradation and structural profiles. These comparative studies offered a new pathway to understand the tunable properties of silk-based biomaterials and would provide important insights for the development of novel silk-based functional materials with controllable physical and biochemical properties in the future.

Effects of temperature and relative humidity on rearing performances of Eri Silkworm (Philosami aricini)

Eri Silkworm (Philosamia ricini) is a delicate, domesticated insect which cannot tolerate diurnal and seasonal fluctuations in the environmental condition. The life cycle of silkworm is influenced by bio-ecological stress during larval period. Deviations in humidity and temperature levels below and above certain critical limits affect larval growth and development of Eri silkworm. In present study, several experiments were performed in four temperatures 20±3ºC, 24±3ºC, 28±3ºC and 32±3ºC each with three relative humidity 50%, 70% and 90% on rearing of Eri silkworm (Philosamiaricini) to study the effect of temperature and relative humidity on larval, cocoon and grainage parameter.Our findings clearly indicated that the 28±3ºC temperature and 70% relative humidity are the best for larval, cocoon and grainage parameter of Eri silkworm (Philosamia ricini).

Impact of light and dark exposure on life cycle duration (days) of Eri silk worm, Philosami aricini l (Saturniidae: Lepidoptera)

The impact of dark and light exposure on life cycle duration (days) were studied on Eri silk worm (Philosamiaricini) at Zoology Department Govt. P.G. Madhav Science College Ujjain. The diseases free laying (DFL’s) were collected from Govt. Sericulture Dept. Indore. Worms were reared under hygienic laboratory conditions. The optimum 25± 2°C temperature and 75±5% Relative humidity were maintained during complete in control, dark (24 hours) and complete light (24hours) condition. The duration of life cycle of the larvae reared in dark was significantly better than the larvae kept in light condition.

Rearing performance of Philosamia ricini (Eri silkworm) in different seasons of Ujjain district

India has the unique distinction of being only country producing all the five commercially traded varieties of natural silk namely Mulberry, Eri, Muga, Temperate tasar and Tropical tasar. The silk produced by Philosama ricini is called Eri silk. Eri silk is known as Non Violence silk or Piece silk. It is also said to be Poor Person’s silk. The Eri silkworm (Philosamia ricini) is multivoltine, holometabolus, non-mulberry, completely domesticated and feed on castor (Ricinus communis) leaves.We observed the effect of different seasons on rearing performance of Eri silkworm in respect of different larval parameters (larval weight, larval length, ERR% and pupation) and cocoon parameter (cocoon weight, pupae weight, shell weight &amp; shell %). Our findings clearly indicated that the rearing performance of Eri silkworm was better in spring season than winter and autumn season of Ujjain district M.P.