Protein stimulatory activity of mikania micrantha, ricinus communis on the silk gland of vth instar eri silk worm samia ricini donovan.

Dr. Mainu Devi / International Journal of Advances in Engineering, Science and Technology (IJAEST) Protein Stimulatory Activity of Mikania
micrantha, Ricinus communis on the Silk
gland of Vth instar Eri silk worm Samia
ricini Donovan.
Department of Zoology, Diphu Govt. College, Karbi Anglong, Assam, India. ABSTRACT
Impact of feeding of Japanese weed leaves (Mikania micranhta),Castor leaves (Ricinus communis) and their combination on the silk gland protein of eri silk worm, Samia ricini Donovan has been investigated. The rearing was conducted at laboratory condition. The larvae were reared on four experimental treatments (Ex tr. 1 – host plant- Mikania micrantha from I instar till maturity; Ex tr. II – host plant- Ricinus communis from I to IV instar larva, the V instar larva fed on Mikania micrantha & Ricinus communis in equal proportion till maturity; Ex tr. III – the host plant - Ricinus communis from I to II instar larvae, the III instar larvae fed on Mikania micrantha till maturity; Ex tr.IV – the host plant - Ricinus communis from I to V instar larvae- the control). In spite of heavy mortality (90%) of 1st instar larva of Ex tr.- I, the survivors (10%) were highly adapted to the new environment of food plant Mikania micrantha. The concentrations of protein in the posterior silk gland (PSG) during V instar larval development were studied. Significantly higher concentrations of protein in posterior silk gland (76.50 ±2.43) during the spinning stage was recorded in the lavae fed on Japanese weed leaves from III instar onward followed by Japanese weed fed larvae from I instar larvae till maturity (75.62±2.72) and control group (73.90±2.78). However, the lowest posterior silk gland protein (66.58±3.90) was recorded in Ex tr.- II. Thus, M. micrantha, a commonly available weed all over can be commercially exploited for better growth and development of eri silkworm and hence the silk productivity and fecundity. Key words : Mikania micrantha, Samia ricini and silkgland protein
I. INTRODUCTION
The eri silkworm is a polyphagous insect and its growth varies with different food plants. The nutritional
value of leaf has been implicated as a major factor in the survival of non-mulberry silkworms
(Pandey,1995)). Many plants contain a variety of metabolites which are harmful as well as beneficial to biotic
stresses, whereas same compounds in plants are beneficial to insects also for their better growth and
development to perpetuate their life style. There are number of plants which are having Insect Growth
Regulatory (IGR) activity, exhibited stimulatory effect on protein synthesis in the haemolymph and posterior
silk gland, when used in higher concentrations they are detrimental to the insects but useful at lower
concentrations particularly for productive insects. The weed plants such as Cassia tora, Lantana camara,
Clerodendron inermae, Tribulus terrestris ,etc. are being tried to increase the silk and egg production in
mulberry silk worm Bombyx mori as well as eri silk worm, Samia cynthia ricini bois. Shivkumar et al (1995 )
reported the weed plant Cassia tora extracts in accelerating the maturity of Bombyx mori. Further,
Mamadapur, (1994 ) & Santosh Kumar (1997) observed that the dusting of Weed plants Lantana camara
and Clerodendium inermae at 5% has significantly increased the cocoon weight, shell weight, and shell
ratio in Bombyx mori. Mane and Patil G. M. (2000) also reported that dusting of Cassia sericea a
commonly available weed in Karnataka, at 20% on 48hr old fifth instar eri silkworm induced maximum larval
weight, shell weight, shell ratio and fecundity . Mikania micrantha a commonly available weed all over is used
by a sizable rearers of Karbi Anglong District of Assam, India for want of host plants particularly at the latter
larval stage when the larvae starts to eat voraciously with a hope of good quality yarn. Further, The feeding of
Ricinus communis leave fortified with 40% aqueous extracts Mikania micrantha leaf significantly improved
larval and cocoon characters in Samia ricini Donovan (Devi and kalita, 2010 ; Devi, 2011). Hence, an attempt
was made to know the impact of food plant Mikania micrantha, Ricinus communis and their combination on
Silk gland protein concentrations of Vth instar Eri silk worm Samia ricini Donovan.
II. METHODOLOGY
Fresh disease free layings (dfls) of Eri silkworm were reared in the laboratory at temperature 22 ± 3
and 78 ± 4% RH. The egg incubation and rearing was undertaken as par the recommended method of
Dr. Mainu Devi / International Journal of Advances in Engineering, Science and Technology (IJAEST) Choudhury (1982a ). Four experimental treatments were developed with different food plants of Mikania micrantha and Ricinus communis as Experimental tr-I (Host plant Mikania micrantha); Experimental tr- II ( Host plant Ricinus communis from I to IV instar larvae. The V instar larvae fed with Ricinus communis and M. micrantha in equal proportion); Experimental tr-III ( Host plant plant Ricinus communis from I to II instar larvae. III instar larvae fed with Mikania micrantha till maturity). Experimental tr-IV( Host plant Ricinus communis considered as control). These treatments were replicated thrice with 100 larvae in each replication.Immediately after IV moult, the Vth instar larvae were collected (5-6 worms) from each experimental rearing at an interval of 24 hours up to spinning stage and used for estimation of soluble protein. The healthy larvae were dissected for collection of silk gland. The silk gland was excised and cleaned with distilled water. A 10% (W/V) homogenate was prepared in 10% TCA and centrifuged at 3000 rpm. The residue was dissolved in 5ml of 1N NaOH, centrifuged and the supernatant was used for protein estimation according to the method of Lowry at al., (1951) using Bovine Serum Albumin as standard. All the data were statistically analyzed and presented in the result. III. RESULT AND DISCUSSION
In the present study, as shown in the table significantly higher concentrations of protein (p<0.050) in PSG
(76.50 ±2.43) during the spinning stage was recorded in the lavae fed on Japanese weed leaves from III instar
onward. It is followed by the Japanese weed fed larvae from I instar till maturity (75.62±2.72) and control
(73.90±2.78) which did not differ significantly. However, the lowest PSG protein concentration (66.58±3.90)
was recorded in the larvae fed on mixed food (Ex tr. II) during V instar larval period which differ significantly
with control and other treatments.
The improvement of PSG protein in the larvae fed on Mikania micrantha from III instar till maturity (Ex.tr-III of table-5) is 3.47% which may be attributed to the stimulatory effect of Japanese weed on protein synthesis in the silk gland during larval period of eri silkworm Samia ricini Donovan. The present findings are in conformity with Mane and Patil, (2000) and Shivkumar et.al, (1995). Mane and Patil, (2000) suggested that some weed plants have certain insect growth regulatory (IGR) activity, when used in higher concentration they are detrimental to the insects but useful at lower concentrations particularly for productive insects. Their findings on exogenous dusting of weed plant Cassia sericea on fifth instar larvae of Samia cynthia ricini attributable to the stimulatory effect on protein synthesis in the silk gland during larval period. Similar trend was also reported in mulberry silk worm Bombyx mori by Shivkumar et.al., in 1995. Thus, M. Micrantha, a commonly available weed all over can be commercially exploited for better growth of Silkworm and hence the silk productivity and fecundity of eri silk worm. Dr. Mainu Devi / International Journal of Advances in Engineering, Science and Technology (IJAEST) Table : Changes in the concentration of silk gland protein (mg/g) during V instar larval development of Samia ricini Donovan fed on different food plants (Mikania micrantha, Ricinus communis and their combinations). Mean 22.76 32.94 38.61 59.11 70.18 75.62 59.84 23.74 Mean 22.18 31.25 36.71 57.57 70.50 73.9 58.28 22.31 22.17 31.62 37.38 58.06 69.94 73.15 58.62 22.78 SE± 0.54 0.46 0.48 0.87 1.86 1.63 1.5 1.62 Dr. Mainu Devi / International Journal of Advances in Engineering, Science and Technology (IJAEST) ACKNOWLEDGEMENT
The author is grateful to the Department of Zoology, Gauhati University, Guwahati, Assam, India for providing immense help and inspiration to undertake the research work on Eri Silk worm. REFERENCES
[1] Devi , M. and kalita,J.(2010) . Effect of feeding Mikania micrantha on the qualititative parameters of silk fibre of Eri Silkworm Samia ricini Donovan. Environment and Ecology. Vol 29 (2A): 783-785. [2] Devi, M.(2011) Fortification of Mikania micrantha extracts with Castor leaves on the productivity of silkworm Samia ricini Donovan. International Journal of Science and Advanced Technology. Vol. 10 : 176-179. [3] Lowry,O.H. ; Roserbrough, N.J.; Farra, L. and Randall, R.J. (1951) Protein measurement with the Folin Phenol reagent. J. Biol. [4] Mane, J.R.; Patil, G.M. (2000) Effect of botanicals having IGR activity on growth & development and economic Eri Silk worm, Samia Cynthia ricini boisd, International Journal of wild silkmoth and silk, 5 : 200-203. [5] Mamadapur, B.B. (1994) Botanicals with IGR activity on Bombyx mori L. M.Sc. (Agrl.) Thesis, University of Agricultural Sciences, [6] Pandey, S.K. (1995) Do leaf tannin affect non-mulberry silkworm ? Indian Silk, 34(8): 21-23. [7] Santosh Kumar, G. H. (1997) Large scale evaluation of insect growth regulatory (IGR) of Lantana camara M.Sc. (Agril) Thesis, University of Agricultural Science, Dharward,1999. [8] Shivkumar, G.R. and Anantharaman, K.V. (1995) Identification of locally available plant rich in phytoecdysteroid and its extraction. Central Sericulture Research and Training Institute, Annual Report for 1995-96, Mysore, pp 95-97.

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