• 제목/요약/키워드: Tasar silkworm

검색결과 43건 처리시간 0.018초

Genetic Variability Within and Among Three Ecoraces of the Tasar Silkworm Antheraea mylitta Drury, as Revealed by ISSR and RAPD Markers

  • Vijayan K.;Nair C. V.;Kar P. K.;Mohandas T. P.;Saratchandra B.;Urs S. Raje
    • International Journal of Industrial Entomology and Biomaterials
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    • 제10권1호
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    • pp.51-59
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    • 2005
  • Genetic diversity within and between populations of Antheraea mylitta Drury was studied using thirty individuals from three ecoraces using 12 ISSR and 10 RAPD primers. Rally, Daba and Modal ecoraces were collected from Chattisgarh, Jharkhand and Orissa states of India respectively. The ISSR and RAPD primers generated $94.7\%$ and $95.6\%$ polymorphism among the 30 individuals. The cluster analysis grouped these individuals according to their ecorace. The intra-ecoracial heterozygosity estimated with ISSR markers were $0.123{\pm}0.18,\;0.169{\pm}0.17\;and\;0.214{\pm}0.17$ respectively for Modal, Raily and Daba ecoraces. Like wise, with RAPD markers the intraecoracial heterozygosity was $0.17{\pm}0.22$ in Modal, $0.229{\pm}0.17$ in Raily and $0.23{\pm}0.19$ in Daba ecoraces. However, the significantly low genetic differentiation (GST) (0.182 for ISSR and 0.161 for RAPD) and the high gene flow (Nm) (2.249 for ISSR and 2.60 for RAPD markers) among the ecoraces revealed that the amount of genetic diversity present among the ecoraces is not significant enough to make drastic genetic drifts among these ecoraces in the near future.

Impact of maternal crowd on the reproductive performance of an ecto-pupal parasitoid Nesolynx thymus (Hymenoptera: Eulophidae)

  • Siddaiah, Aruna Ambadahalli;Danagoudra, Manjunath
    • International Journal of Industrial Entomology and Biomaterials
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    • 제29권1호
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    • pp.128-134
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    • 2014
  • Nesolynx thymus Girault (Hymenoptera: Eulophidae) is one among 20 hymenopteran parasitoids reported to attack the uzi fly, Exorista bombycis, which in turn infests the silkworm, Bombyx mori accounting a cocoon yield loss of 10-20%. A host of factors viz., age and size of host, age and size of parasitoid, availability of host, temperature and quality of host are reported to influence the reproductive efficiency of the parasitoids. In the present study an attempt was made to record the influence of foraging parasitoid density on their reproductive performance. Three day-old uzi pupae were offered to varying numbers (1 - 10) of 2 day old Nesolynx thymus adults for parasitization. The progeny production per pupa (84.44 - 132.77) increased significantly with increase in the number of foraging parasitoid adults (1 - 10) however, progeny production per female decreased. The sex ratio (M : F) (1:25.49 - 1:1.53) decreased significantly with increase in foraging parasitoid adults. The morphometric parameters except female abdomen width of first generation parasitoid showed significant negative correlation with number of foraging adults. However, correlation between the parasitoid size in first generation and their reproductive performance was nonsignificant.

Effects of forestry host plants, rearing seasons and their interaction on cocoon productivity of tropical tasar silkworm, Antheraea mylitta in uttarakhand

  • Bhatia, N.K.;Yousuf, Mohd.
    • International Journal of Industrial Entomology and Biomaterials
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    • 제30권2호
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    • pp.31-39
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    • 2015
  • Antheraea mylitta Drury (Lepidoptera: Saturniidae) is a commercial silk producing forest insect of India, but it has never been experimented in Uttarakhand state in spite of the huge availability of its forestry host plants. This is the first study on A. mylitta in Uttarakhand. The goal of this study is to introduce forest based commercial rearing of A. mylitta, in tropical forest areas of Uttarakhand to reduce poverty among forest dependent people. In current study, we assessed the effect of seven forest tree species, rearing seasons, and their interactions on cocoon productivity of Daba (bivoltine) ecorace of A. mylitta in the New Forest of FRI, Dehra Dun during 2012 and 2013 and collected the data that was analysed by two-way completely randomized block factorial design. Post HOC Tukey's HSD test was carried out to compare the homogeneous pairs of means. We also carried out Evaluation Index analysis to rank the tested forestry host plants for better growth and development of A. mylitta under the climatic condition of Uttarakhand. Analysis of variance indicated that cocoon yield of A. mylitta differed significantly between rearing seasons (DF=1, F=88.24, p<0.05) and host plants (DF 6, F= 368.63, p<0.05); however, their interactions were found insignificant (DF=6, F=0.99, p>0.05). In first rearing season of July-August, there was higher cocoon yield than the second season of September-November. Results indicated that Terminalia alata fed larvae showed significantly higher cocoon yield (164.11 cocoons/300 larvae); followed by, T. tomentosa (148.89 cocoons), T. arjuna (140.00 cocoons) and Lagerstroemia speciosa (129.47 cocoons) fed larvae. Whereas, Lagerstroemia tomentosa fed larvae that was used by the first time in India, showed lowest cocoon yield (48.81 cocoons), followed by T. chebula (72.53 cocoons) fed larvae. Cocoon yield of T. tomentosa and T. arjuna fed larvae of A. mylitta did not differ significantly with each other.