International Journal of Latest Trends in Engineering and Technology Vol.(10)Issue(2), pp.150-152 DOI: http://dx.doi.org/10.21172/1.102.24 e-ISSN:2278-621X EFFECT OF EXTRINSIC FACTORS ON THE EGG LYING BEHAVIOR OF SILK PRODUCING

Kumari Shobha Rani1

Abstract- Silk is the beautiful gift of nature which has great commercial importance. Production of silk is directly dependent on eggs of silk insects .Laying of eggs by silk insects depends upon so many factors. So, the relative impacts of extrinsic factors namely different temperature, photoperiod and humidity on the egg laying of three different non-mulberry silk (tasar, eri and muga) have been evaluated in this project. Result will help our poor people in the production of more silk. This project had been taken in consideration especially to enhance the growth of silk industry. Keywords-Silk insects, Temperature, Photoperiod and Humidity.

1. INTRODUCTION Silk is the beautiful gift of nature which has great commercial importance and plays vital role for the invigoration of our rural economy and social development. Silk producing insects belonging to families Bombicidae band of order are famous for producing beautiful silk of great commercial interest. These silk producing insects are abundant in tropical and temperate silk producing belts of our country and are usually reared on the foliages of mulberry and non- mulberry food plants under domesticated, semidomesticated and wild conditions during different seasons. Our country has the unique distinction of being the only country in the world which produces all the four popular varieties of natural silk namely mulberry, tasar, eri and muga. Among these mulberry silk is produced by Bombyxmori under domesticated condition and these insects are reared on the chopped foliages o0f mulberry food plants known as Morus alba and Morus indica. A part from this three others silk producing insects such as tasar, eri and muga constitute the non-mulberry sector and these insects are usually reared on the foliages of different food plants in the forest areas as under wild or semidomesticated conditions. Thus the silk world is constituted of mulberry, non-mulberry and other products. It is interesting that the climatic and environmental characteristics of India make her the homeland of various silk producing insects and their food plants. Among the non-mulberry sector the golden yellow muga silk of Assam is secreted by a multivoltine caterpillar known as assamensis. This species is widely distributed and cultured in Bramhaputra valley on Som.(Machilusbombycida). The brick red or white eri silk of India is produced by Philosomia ricni a multivoltine silkworm feeding mainly on castor leaves(Ricnus communis). Tasar silk is produced by different species of Antheraea. The prominent among them are Antheraea mylitta, Antherae pernyi, Antheraea yamamai, Antheraea roylri, Antheraea proylei and many others. These species are wild and polyphagous and are usually reared on the foliages of different tasar host plants found in the forest areas in different regions of the world. At the global level the principal tasar producing countries are China, India, Japan and Sri Lanka. We rank second among global producer of tasar silk.

2. MATERIAL AND METHOD The relative impacts of extrinsic factors namely different temperature, photoperiod and humidity on the egg laying of three different non-mulberry silk moths (tasar, eri and muga) have been evaluated.The relative impacts of different temperatures such as 10oC, 15oC, 20oC, 25oC, 30oC and 35oC, different photoperiods, 0hr., 6hrs., 12hrs., 18hrs., and 24hrs. as well as different humidity 60%, 70%, 80%, and 90% on the breeding manifestations of three different non-mulberry silk insects have been observed during the present experiment.

3. RESULTS The relative effects of different temperatures, photoperiods and relative humidity on the egg laying behaviors of three different types of saturniidae silk moths have been examined and results so obtained have been presented in the table 1, 2 and 3.

1 P.G. Department of Zoology, Magadh University, Bodh Gaya. India Effect Of Extrinsic Factors On The Egg Lying Behavior Of Silk Producing Insects 151

Table: 1 Table showing the relative effect of different temperatures on the egg lying behavior of three different non-mulberry silk moths Significant at 0.5 S.NO. Different Silk moths % level Temperatures Tasar Eri Muga

1 10oC - +- --

2 15oC +- +- ++

3 20oC +- + + H.S.

4 25oC + ++ +-

5 30oC ++ + +-

6 35oC +- +- -

Table : 2 Table showing the relative effect of different photoperiods on the egg lying behavior of three different non- mulberry silk moths Significant at 0.5 S.NO. Different Silk moths % level Photoperiods Tasar Eri Muga

1 0hrs +- - +

2 6hrs ++ + +

3 12hrs + ++ +- H.S.

4 18hrs +- +- +-

5 24hrs - +- +-

Table : 3 Table showing the relative effect of different humidity on the egg lying behavior of three different non-mulberry silk moths Significant at 0.5 S.NO. Different Silk moths % level Humidity Tasar Eri Muga

1 60% +- + ++

2 70% + ++ +- Kumari Shobha Rani 152

3 80% +- +- +- H.S.

4 90% + +- +-

++ : Highest -+ : Normal + : Average - : Nil H.S. : Highly Significant

Tables indicates that tasar moths prefer high temperatures of 30oC, eri moths moderate temperature of 25oC and muga moths preferred low temperatures of 15oC for maximum fecundity. As far as photoperiods were concerned the tasar moths preferred short day photoperiod of 6hr. and eri and muga moths 12hrs. for maximum fecundity. The relative humidity of 80% for tasar, 70% for eri and low humidity of 60% for muga had been observed to be the suitable R.H. for three different silk moths. It is, thus clear that different moths differ in respect of said factor for their egg laying performances.

4. DISCUSSION Sericulture is the science that deals with the production of silk by rearing of silkworm. Silk is called the queen of textiles due to its glittering luster, softness, elegance, durability, and tensile properties. So, it is very important to take proper care of this from the very beginning i.e. write from egg laying behavior of silk insects. So that more and more healthy insects could be produced. and that will give strong support in enriching the silk industry. Tasar moths prefer high temperatures of 30oC, eri moths moderate temperature of 25oC and muga moths prefer low temperatures of 15oC for maximum fecundity. Ahsan et al (1975), Henneberry, T.J. and Leal, M.P. (1979) also worked on the effect of temperature on egg laying behavior of silk producing insects. . Purihot, M.L., Khetri, A.K. and Aggarwal R.K. (1975) shown their work on effect of nutrition on Fecundity, longevity and egg viability of silk insects. While Thomas, A. et al (1982) worked on the relationship between pupal size and egg production in reared female Antiheroes Polyphemus. Vishwakarma, S. R. et al (1976) very beautifully showed the effect of photoperiod on egg laying in A. proylei.. Vishwakarma, S. R. et al (1976) discussed in details about the role of temperature and humidity on growth and development of silkworm including recent studies on heat shock protein. Study also discusses the influence of air and light on silkworm development. V. K. Rahmathulla, also described about the management of climatic factors during silkworm rearing. S. K. Mathur, D. R. Pramanik, S. K. Sen, and G. S. Rao, 1988described very wee about the effect of seasonal temperature and humidity on ovulation, fecundity and retention of eggs in silk moth, Bombyx mori L.(Lepidoptera:Bombycidae),”

5. REFERENCES [1] Ahsan et al (1975) : Effect of temperature and RH on egg laying behavior of tasar silk worm, A. Mylitta D. Annual report C.T.R.S Ranchi, Govt. of India Proj. 2-3. [2] Biram, N. M.(2002) : How silkworms lay eggs in monolayers Indian silk, 44(1) : 8. [3] Henneberry, T.J. and Leal, M.P. (1979) : Effect of temperature, photoperiod, light intensity moth age and mating frequencies on oviposition and egg via ability on pink ball worm Pectinophora J. Econ. Ent, 72 : 489-492. [4] Purihot, M.L., Khetri, A.K. and Aggarwal R.K. (1975) : Effect of nutrition on Fecundity, longevity and egg viability of Laphygma exiqua Hb.(Lepi : Noctuidae). Ind. J. Ent. 37(1) : 7-10. [5] S. K. Mathur, D. R. Pramanik, S. K. Sen, and G. S. Rao, (1988. )“Effect of seasonal temperature and humidity on ovulation, fecundity and retention of eggs in silk moth, Bombyx mori L.(Lepidoptera:Bombycidae),” in Proceedings of the National Seminar on Advances in Economic Zoology, p. 48, Jodhpur, India, [6] Thomas, A. et al (1982) : Relationship between pupal size and egg production in reared female moth Antheraea Polyphamus. Ann. Ent. Soc. Amer., 75(1) : 107. [7] Vishwakarma, S. R. et al (1976) : Effect of photoperiod on egg laying in A. proylei. Ann. Rep. CTRS, pp. 18-21. [8] V. K. Rahmathulla (2012), Management of Climatic Factors for Successful Silkworm (Bombyx mori L.) Crop and Higher Silk Production: A Review, Psyche, Volume Article ID 121234, 12 pages [9] V. K. Rahmathulla,( 1999) “Management of climatic factors during silkworm rearing,” The Textile Industry and Trade Journal, pp. 25–26,