INVASIVE SPECIES MICRANTHA AN ENVIRONMENTAL THREAT, ITS CONTROL WITH REFERENCE TO ERI SILK WORM

MAINU DEVI

Department of Zoology, Diphu Govt. College Affiliation : Assam University, silchar, Assam, E-mail: [email protected].

Abstract: Biological invasion is one of the three most difficult environmental problem in the world. The control of invasive species is one of the most urgent challenges in ecology today. kunth ex H.B.K. is one of the 100 world’s worst alien species and pose a serious threat to biodiversity and ecosystem. Mikania has been shown to have allelopathic properties that can inhibit the growth of . Mechanical control method of Mikania are labour intensive, expensive and not effective in longer term. Efforts has been made to use biological control mechanism to sustainably manage Mikania. According to the information provided by the Silk worm rearers Mikania micrantha is used by a sizable Eri Silk rearers in Karbi Anglong District of Assam, India for want of host plants , particularly at the latter larval stages when the larva starts to eat voraciously. In this paper the nutrient contents of Mikania micrantha and the impact of feeding Mikania micranhta and Ricinus communis ( The primary food ) on silk quality parameter (denier, tenacity, elongation at break and defective cocoon) of eri silk worm, Samia ricini Donovan have been investigated. Significantly finer denier (1.786±0.070), higher breaking strength or tenacity (3.590±0.150) and lower percentage of elongation at break (24.029±1.557) were recorded in the larvae fed with Mikania leave from III instar till maturity. No defective cocoons were recorded in any case under the laboratory condition conducted under investigation. The equality parameters in Mikania micrantha and Ricinus communis examined by student t- test subscribes the view that moisture (70.90%), ash (12.54%),Calcium (1.63%), and phosphorus (0.57), are significantly higher in Mikania micrantha while the percentage of nitrogen (3.64%), crude protein (22.86%), and crude carbohydrate (33.27%) on dry weight basis in Mikania micrantha did not differ significantly with Ricinus communis (nitrogen : 3.66% ; protein : 22.85% and carbohydrate: 34.30%). Thus Mikania micrantha a commonly available weed all over can be commercially exploited for better growth, development and silk yield of Samia ricini Donovan. Exploitation of Mikania micrantha to this end would also help in controlling its spread to new regions and conserve biodiversity.

Key Words: Mikania micrantha, Invasive species, Biodiversity, Biological control, Samia ricini.

I. INTRODUCTION and Mitchell (1998), reported that Mikania micrantha interferes with soil nitrification process Biological invasion is one of the major threats to and also reduces the carrying capacity of pastaur. native Biodiversity and Ecosystem. Mikania In Australia Mikania has been declared a class 1 micrantha ex H.B.K. (Fig1a), commonly known as weed in Queensland under the Rural Land Bitter Vine, a perennial weed of the Order , Protection Act. Mikania has also been Family , has been listed as one of the 100 consistently ranked amongst the top three worst worst invasive alien species in the world (Lowe et weed by member countries of the Secretariat of al.2001). It is known for its vigorous and rampant the Pacific community (SPC). Mikania causes a growth grows best where fertility , organic matters major menace in natural forests, agricultural , moisture, humidity are all high. It is known by systems specially tea , rubber and other plantation different names in different parts of the world; crop in North East and Southwest India (Sankaran American rope, Chinese creeper and Mile-a-minute in and Sreenivasan, 2001). Mikania debris English ;Japani Habi in India; Chinesischer incorporated into soil was also shown to inhibit Sommerefeu in German ; Liane americaine in French germination and seedling growth in some crops. ; Ovaova in Fijian etc. It occurs in agricultural areas, According Pacific Island Ecosystem at Risk coastland, natural forests, shrubs lands, urban areas, (PIER) information much of the works on Mikania wetlands etc. Once established M. micrantha can has been carried out on its eradication and have a major impact on natural ecosystems, in biological control. Various Bio-control projects particular forest communities (Fig1b). This species against this weed have been carried out since can smother native vegetation, eventually killing 2002 by the National Agricultural Research many plants including trees, decreasing Institute (NARI) and Cocoa Research Institute. biodiversity. A native of Central and South Studies on Mikania has been shown to America, Maxico and it was have allelopathic properties i.e. releases chemicals introduced into India after the II World War to that can inhibit the growth of plants. Li-ying, camouflage airfields and is one of the most Guang-Yan, Chen, Peng and Li- Flanglan (2007), widespread and problematic weeds in the Pacific while studied on energetic cost of Mikania micrantha region. The seeds are dispersed by wind or in leaves observed that a variety of secondary clothing or hair of animals. Vegetatively it metabolites like Phenolics, Flavonoids, Alkaloids and reproduces from broken stem fragments. Waterhouse Terpens can be released by volatilization, lixiviation

Proceedings of 31st Research World International Conference, Saint Petersburg, Russia, 8th-9th July 2017 8 Invasive Species Mikania Micrantha An Environmental Threat, Its Control With Reference To Eri Silk Worm of aerial parts and decomposition of plant debris in II. MATERIALS AND METHODS the soil. The investigatory works of Singh and Benchamin (2002) on various botanicals suggest that 2.1) Nutrient contents of Mikania micrantha. many secondary metabolites such as phenolics, The healthy leaves of Mikania micrantha were Glycocides, Alkaloids, Terpenoids, etc. that occur in collected from in and around of Diphu town and after plants exhibiting variation in quality as well as estimating the moisture contents using electronic quantity operating as specific olfactory and gustatory moisture analyzer (Startorius, model MA35) the leaf stimuali. It is further established that the weed plants samples are shade dried for three days. The dried such as Cassia tora, Lantana camara, Clerodendron samples were transferred to hot air oven at 70ºC until inermae, Tribulus terrestris, etc. release these constant weight was obtained. The samples were metabolites and are being tried to increase the silk ground into fine powder and preserved in butter paper and egg production in Mulberry silk worm Bombyx bags for chemical analysis according to the following mori as well as Eri silk worm, Samia cynthia ricini method. Bois. At lower concentrations these secondary metabolites increase the larval and cocoon characters Total nitrogen was estimated by Microkjeldahl and thereby silk yield in both eri and mulberry method. ; Crude protein was derived using the factor silkworm ( Mane and Patil, 2000). These metabolites %N X 6.25;Total carbohydrate was estimated using have stimulatory effect on protein synthesis in the silk the method of Dubios et al., (1956); Crude fat was gland during larval period , thus leading to the determined from an oven dried sample using a increased silk output in Eri and Mulberry silkworm . Soxhlet extraction apparatus (AOAC, 1970); Ash was The leaves of weed plant Mikania micrantha had been determined by the AOAC, 1970 method; found to have significant effect on qualititave Phosphorous content was determined parameters of eri silk worm, Samia ricini Donovan Spectrophotometrically using UV VIS while feeding the Eri silk worm castor leaves Spectrophotometer 118; Iron content was determined fortified with its extracts (Devi , M., 2010). Keeping by Spectrophotometrically using UV VIS all this in view the present study has been undertaken Spectrophotometer 118; Calcium content was to know the nutrient contents of the invasive splecies determined according to AOAC, 1970. Mikania micrantha and the effect of its feeding on quality parameter (Denier, Tenacity, Elongations and All the estimation was done on dry weight basis Defective Cocoon percentage) of silk fibre of Eri in triplicate and the mean was recorded and compared Silkworm Samia ricini Donovan. with analyzed data of nutrient contents of castor leaves.

2.2) Silk Quality of Eri Silk worm 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 were undertaken as per the recommended method of Choudhury (1982 ). Four experimental treatments were developed with different food plants of Mikania micrantha and Ricinus communis ; 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 Fig 1b. Mikania micrantha decreasing 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). The Physical characteristics of silk fibre such as Denier, Tenacity, Elongations and Defective cocoon percentage were calculated and subjected to statistical analysis.

III. RESULTS AND DISCUSSIONS

The equality parameters in Mikania micrantha and Ricinus communis examined by student t- test is presented in Table1and Fig 2 subscribes the view that Fig 1a: The invasive plant Mikania micrantha.Biodiversity of moisture (70.90%), ash (12.54%),Calcium (1.63%), Natural forest.

Proceedings of 31st Research World International Conference, Saint Petersburg, Russia, 8th-9th July 2017 9 Invasive Species Mikania Micrantha An Environmental Threat, Its Control With Reference To Eri Silk Worm and phosphorus (0.57), are significantly higher in determining factor, influencing the other biochemical Mikania micrantha ( P<0.01),while the percentage of nutrients affects the growth of silkworm larvae nitrogen (3.64%), crude protein (22.86%), and crude (Narayanaprakash et. al. 1985 ). carbohydrate (33.27%) on dry weight basis in Eri silkworm reared on Mikania micrantha, Mikania micrantha did not differ significantly with Ricinus communis and their combination have Ricinus communis (nitrogen : 3.66% ; protein : profound effect on the silk quality parameter (Denier, 22.85% and carbohydrate: 34.30%) or they were Tenacity and Elongation at break). Significantly finer statistically at par. Thus, it is evident that the nutrient denier (1.786±0.070), higher breaking strength or contents of weed plant Mikania micrantha and tenacity (3.590±0.150) and lower percentage of Ricinus communis, the primary food plant of Eri silk elongation at break (24.029±1.557) were recorded in worm are identical. the larvae fed with Mikania leave from III instar till In the present investigation of biochemical maturity as shown in Table 2. study on Mikania leaves revealed the occurrence of quite a significant concentration of major and Finer silk fibres have higher breaking strength and micronutrients which could have accelerated the lower percentage elongation at break (Rajkhowa, growth and development of Eri silk moth and thereby 2000). It is also established fact that lower the single the silk output. It is very well established fact that the cocoon filament denier, better is the quality of moisture plays a very important role in the cocoons (Vasumathi, 2000). A lower denier implies development of silkworm. Leaf moisture a primary finer silk filament and hence is more desirable.

Table 1: Nutrient contents of Mikania micrantha and Ricinus Communis.

**Significant at P (<0.01) ; NS : Not Significant

Proceedings of 31st Research World International Conference, Saint Petersburg, Russia, 8th-9th July 2017 10 Invasive Species Mikania Micrantha An Environmental Threat, Its Control With Reference To Eri Silk Worm Table-2 Silk quality parameter of eri silkworm Samia ricini Donovan reared on Mikania micrantha, Ricinus communis and their combination.

The finer silk filament may be attributed to the [3] [3] E.IIzuka, ‘Physical properties of silk thread from increased protein synthesis particularly the fibrion cocoons of various wild silk-moth including domestic silkmoth’. Int. J. wild silkmoth & silk. 5 : 266-269, 2000. synthesis in the posterior silk gland of Eri Silk Worm [4] [4] G.H. Santosh kumar, Rajasekhargouda and Mane, which in turn influences the fibre fineness. These ‘Effect of dusting some plant products on quantitative and findings are in conformity with the findings of qualitative characters of Mulberry silk’. Bull. Acad. Ser 4(1) Santoshkumar, Rajashekharagouda and Mane (2000), 75-77,2000. [5] [5] J.R. Mane, G.M.. Patil, ‘Effect of botanicals having IGR who obtained lowest denier produced by the activity on growth & development and economic Eri Silk silkworm fed with mulberry leaves dusted with weed worm, Samia Cynthia ricini boisd’. International Journal of plant Lantana camara. Further, in the present wild silkmoth and silk, 5 : 200-203,2000. investigation no defective cocoons in any case under [6] [6] K.Singh, Chaoba and K.V. Benchamin , ‘A Bibliography on ericulture. Central Muga and Eri Research laboratory condition were noticed which further & Training Institute, Jorhat, Assam. Eri Silk worm, Samia proved better quality of cocoons, hence, better quality Cynthia ricini boisd’. International Journal of wild silkmoth of silk fibre produced by Eri silkworm at different and silk, 5 : 200-203,2000. treatments. [7] [7] K.V.Sankaran, M.A. Sreenivasan, ‘Status of Mikania infestation in the western ghat’. In: K.V.Shankaran, S.T. Murphy, H.C. Evans, eds. ‘Allien weeds in moist tropical CONCLUSION zones, bans and benefits’, Kerela Peechi, India. Kerela Forest Research Institute. Pp.67-76,2001. The above observations have indicated that foliar [8] [8] Li-ying, N.Guang-Yan, B.M Chen and S.L. Peng, ‘Energetic cost of leaf construction in the invasive weed constituents of Mikania micrantha have a strong Mikania micrantha H.B.K. and its co-occurring species’. bearing on quality of silk fibre of Eri silkworm and Botanical studies, 48 : 331-338,2007. thus, it can be exploited for increasing the silk [9] [9]. M. Devi, ‘An Investigation on growth development and production commercially. As the mechanical control yield of silkworm Samia ricini reared on Castor and Japanese weed in Karbi Anglong District’. Ph.D. Thesis, method of Mikania are labour intensive, expensive Gauhati University, Assam (India),2010. and not effective in longer term the biological control [10] [10] R. Narayanaprakash, K. Periaswami and S. mechanism can help in controlling its spread to new Radhakrishnan,, ‘ Effect of dietary water content on food regions and conserve biodiversity. utilization and silk production in Bombyx mori L. (Lepidoptera : Bombycidae)’. Ind. J. Seric. 24 : 12-17,1985. [11] [11] R. Rajkhowa , ‘Structure property correlation of non- REFERENCES mulberry and mulberry silk fibre’. International J. of Wild Silkmoth. Vol. 5: pp 287-298,2000. [1] [1] B.V. Vasumathi, ‘An analytical study of the silk reeling operation in Karnataka’, Ph.D. Thesis, Indian Institute of [12] [12] S. Lowe, M.Brown, S.Boudjelas, and M. De Poorter, Science, Bangalore, 2000. ‘100 of World’s Worst Invasive Alien Species: A selection [2] ]2] B.M. Waterhouse, A.A. Mitchell, ‘Nothern Australia from the Global Invasive Species’ Database. The Invasive Quarantine Strategy : weeds target list’. Second edition. Species Specialist Group (ISSG) 12PP,2001. Australian Quarantine & Inspection Service, Miscellaneous [13] [13] S. N.Chaudhury, Eri Silk Industry, published by Publication NO.6/98,1998. Directorate of Sericulture& Weaving, Govt. of Assam, pp. 16-114, 1982. 

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