Review : Mating Behaviour in Mulberry Silkworm, Bombyx mori (L.)

( N. M. Biram Saheb ),( Tribhuwan Singh ),( H. K. Kalappa ),( B. Saratchandra ) 한국잠사학회 2005 International Journal of Industrial Entomology Vol.10 No.2

Mating is an essential behavioural social event in the life cycle of silkworm, Bombyx mori (L.) for the perpetuation of population. A number of intrinsic and extrinsic factors and extrinsic factors and events of significant importance are involved in successful mating and egg deposition by an adult silk moth which besides biochemical, physiological and environmental factors also includes attraction of reproductively competent male and female moth for mating, duration and frequency of mating, age of moth at the time of mating, reuse of male moth in the production of eggs etc. An attempt has been made in this review article to elucidate briefly the behaviour of male towards female moth after eclosion, impact of duration and frequency of mating on egg deposition and oviposition, reuse of mated male moth in the production of quality and quantity eggs etc. in the silkworm, B. mori and its significance in silkworm seed production.

Mating Behaviour in Mulberry Silkworm, Bombyx mori (L.)

Saheb N. M. Biram,Singh Tribhuwan,Kalappa H. K.,Saratchandra B. Korean Society of Sericultural Science 2005 International Journal of Industrial Entomology Vol.10 No.2

Mating is an essential behavioural social event in the life cycle of silkworm, Bombyx mori (L.) for the perpetuation of population. A number of intrinsic and extrinsic factors and events of significant importance are involved in successful mating and egg deposition by an adult silk moth which besides biochemical, physiological and environmental factors also includes attraction of reproductively competent male and female moth for mating, duration and frequency of mating, age of moth at the time of mating, reuse of male moth in the production of eggs etc. An attempt has been made in this review article to elucidate briefly the behaviour of male towards female moth after eclosion, impact of duration and frequency of mating on egg deposition and oviposition, reuse of mated male moth in the production of quality and quantity eggs etc. in the silk-worm, B. mori and its significance in silkworm seed production.

Seasonal Impact of Microsporidian Infection on the Reproductive Potential of Silkworm, Bombyx mori L. (Lepidoptera: Bombycidae)

Mohanan N. Madana,Krishnan N.,Mitra P.,Das N. K.,Saratchandra B.,Haldar D. P. Korean Society of Sericultural Science 2005 International Journal of Industrial Entomology Vol.11 No.2

Impact of microsporidian infection and season on reproductive potential of Bombyx mori L. was investigated in the laboratory. Microsporidian infection significantly (P<0.01) reduced fecundity and hatching and increased sterility and mortality of eggs. Among the microsporidia, Nosema sp. 2 infected silkworm produced eggs with least fecundity and hatching percent as well as highest dead and sterile eggs followed by Nosema sp. 1 and N. bombycis. Microsporidia, in general, significantly reduced fecundity and hatching percent of eggs and increased number of dead and sterile eggs in all the three seasons except N. bombycis in July - August (S3) and Nosema sp. 2 in January February (S1). Since, seed production is the anchor sheet of mulberry sericulture, coefficient of egg lying is considered as an important aspect and the industry quite often facing shortage of disease free layings. The present study indicates that B. mori is more susceptible to microsporidia during S2 followed by S3 and S1 and Nosema sp2. is most virulent followed by Nosema spl. and N. bombycis.

Research Articles : Evaluation of ISSR and RAPD Markers for the Detection of Genetic Diversity in Mulberry (Morus spp.)

( M. Venkateswarlu ),( B. Surendra Nath ),( B. Saratchandra ),( S. Raje Urs ) 한국잠사학회 2004 International Journal of Industrial Entomology Vol.9 No.2

Evaluation of ISSR and RAPD Markers for the Detection of Genetic Diversity in Mulberry (Morus spp.)

Venkateswarlu, M.,Nath, B.Surendra,Saratchandra, B.,Urs, S.Raje Korean Society of Sericultural Science 2004 International Journal of Industrial Entomology Vol.9 No.2

The present study was carried out to evaluate the ISSR and RAPD markers for their efficiency as genetic marker systems to establish the relationships between 18 mulberry genotypes. A total of 36 from 56 (64%) RAPD primers and 12 from 48 (25%) ISSR primers produced reproducible amplification patterns. A high proportion of polymorphic bands ranging from 44 to 91% was observed respectively with RAPD and ISSR markers. The average Resolving Power (Rp) of ISSR primers was higher than RAPD primers. The ISSR primers, UBC 825, 868 and 873, and RAPD primers, UBC 712, 720 and 729, possessed the highest Rp values and could in each instance distinguish all the 18 genotypes. Similarity matrix values were estimated based on Jaccards coefficient, considering 109 polymorphic ISSR and 212 polymorphic RAPD bands and two dendrograms were constructed. The dendrograms obtained with ISSR and RAPD markers distinguished the eight exotic genotypes from the ten indigenous (Indian) genotypes. A significant correlation value (r=0.959; p=0.001) for the cophenetic matrix between the RAPD and ISSR matrices was observed. The results indicated that the ISSR and RAPD markers could assist in the differentiation of genotypes and permit the determination of genetic distances that might be exploited by mulberry breeders in improvement programs.

Determination of Economic Threshold Level of Whitefly, Dialeuropora decempuncta (Quaintance and Baker) in Mulberry, Morus alba L.

Bandyopadhyay, U.K.,Santhakumar, M.V.,Saratchandra, B.,Das, K.K. Korean Society of Sericultural Science 2002 International Journal of Industrial Entomology Vol.4 No.2

Whitefly, Dialeuropora decempuncta (Quaintance rind Baker) (Homoptera: Aleyrodidae) has attained the major pest status in mulberry, causing 24% crop loss by sucking the leaf juice and manifesting leaf curl, chlorosis and sooty mould desease during monsoon season in West Bengal, India. The assessment of economic threshold revel is an essential component for formulating the management practices. Experiments were carried out by inoculating five different densities of whitefly viz.,10, 20, 30, 40 and 50 adults on covered mulberry plants in glass houses. From the findings, it was observed that irrespective of released density, no crop loss was observed in the initial period. But with the passing of days, the percent crop loss was increased rapidly. The linear relationship between percent crop loss and number of adults released was established to highlight the significance of economic threshold. The statistical analysis in the linear form of equation showed that initial population of 10, 20, 30, 40 and 50 whiteflies/plant causes 3%, 12%, 21%, 30% and 40% crop loss in a period of 28 days which is equivalent to 57 kg, 247 kg, 437 kg, 626 kg and 816 kg leaf/acre. Execution of management practices (spray of 0.01% monocrotophos) are economical to the farmer whenever the loss is above 247 kg/acre, but below which application of control measures is not economical. From this study, it can be inferred that the economic threshold level far whitefly is 20 individuals/plant beyond which a farmer has to take appropriate control measures.

Review : Sampling, Surveillance and Forecasting of Insect Population for Integrated Pest Management in Sericulture

( R. N. Singh ),( M. Maheshwari ),( B. Saratchandra ) 한국잠사학회 2007 International Journal of Industrial Entomology Vol.8 No.1

Pest monitoring through field surveys and surveillance helps in forecasting the population build up of pest. It reduces the load of pesticides application and forms the basis of Integrated Pest Management in sericulture. Common sampling techniques for quantifying pest populations and damage caused by them are reviewed emphasizing the need for quick and simple sampling methods. Various direct and indirect sampling methods for establishing pest populations are discussed and methods have been discussed to use indirect sampling method under IPM programme in sericulture. The use of pheromone lures and traps forms one of the important ingredients of integrated pest management, which calls for integration of all available methods in a cost effective and environmental friendly manner offering consistent efficacy. Silk-worms feed on the variety of silk host plants and spin cocoons. Each silk host plant is attacked in the field by number of insect pest species. Several pests are common to mulberry, tasar, oak tasar, muga and eri host plant but pest status and seasonal abundance differs from each crop. The key pests are serious perennially occurring persistent species which cause considerable yield loss every year on large areas and require control measure. Regular occurrence of minor pest is noticed but sudden increase in its population is not known. The occasional pests are sporadic but potential causing sufficient damage. Silk losses due to attack of all the pests have not been calculated. However, information on pest biology and ecology, and control practices being practiced is available but the period of outbreak of major pests and predators on silkworms and its host plant needs to be reinvestigated. Pest and predators forecasting based on surveillance information may provide an opportunity to minimize the losses, particularly to reduce expenditure involved in pest management.

Sampling, Surveillance and Forecasting of Insect Population for Integrated Pest Management in Sericulture

Singh, R.N.,Maheshwari, M.,Saratchandra, B. Korean Society of Sericultural Science 2004 International Journal of Industrial Entomology Vol.8 No.1

Pest monitoring through field surveys and surveillance helps in forecasting the population build up of pest. It reduces the load of pesticides application and forms the basis of Integrated Pest Management in sericulture. Common sampling techniques for quantifying pest populations and damage caused by them are reviewed emphasizing the need for quick and simple sampling methods. Various direct and indirect sampling methods for establishing pest populations are discussed and methods have been discussed to use indirect sampling method under IPM programme in sericulture. The use of pheromone lures and traps forms one of the important ingredients of integrated pest management, which calls for integration of all available methods in a cost effective and environmental friendly manner offering consistent efficacy. Silk-worms feed on the variety of silk host plants and spin cocoons. Each silk host plant is attacked in the field by number of insect pest species. Several pests are common to mulberry, tasar, oak tasar, muga and eri host plant but pest status and seasonal abundance differs from each crop. The key pests are serious perennially occurring persistent species which cause considerable yield loss every year on large areas and require control measure. Regular occurrence of minor pest is noticed but sudden increase in its population is not known. The occasional pests are sporadic but potential causing sufficient damage. Silk losses due to attack of all the pests have not been calculated. However, information on pest biology and ecology, and control practices being practiced is available but the period of outbreak of major pests and predators on silkworms and its host plant needs to be reinvestigated. Pest and predators forecasting based on surveillance information may provide an opportunity to minimize the losses, particularly to reduce expenditure involved in pest management.

Genetic variability within and among three ecoraces of the tasar silkworm Antheraea mylitta Drury, as revealed by molecular markers

K. Vijayan,C. V. Nair,P. K. Kar,T. P. Mohandas,B. Saratchandra,S. Raje Urs 한국잠사학회 2005 International Journal of Industrial Entomology Vol.10 No.1

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. Raily, 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 ± 0.18, 0.169 ± 0.17 and 0.214 ± 0.17 respectively for Modal, Raily and Daba ecoraces. Like wise, with RAPD markers the intraecoracial heterozygosity was 0.17 ± 0.22 in Modal, 0.229 ± 0.17 in Raily and 0.23 ± 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.

Genetic Variability in the Natural Populations of Daba Ecorace of Tasar Silkworm (Antheraea mylitta Drury), as Revealed by ISSR Markers

T. P. Mohandas,K. Vijayan,P. K. Kar,A. K. Awasthi,B. Saratchandra 한국잠사학회 2004 International Journal of Industrial Entomology Vol.8 No.2

Genetic diversity within the natural populations of Daba ecorace of Antheraea mylitta Drury was studied using individual silkworms collected from the South Singhbhum district of Jharkhand state of India with 21 inter simple sequence repeat (ISSR) primers. A total of 148 bands were produced, of which 79% was polymorphic. The pair wise genetic distance among the individuals varied from 0.186 to 0.329. The dendrogram grouped the individuals into 3 major clusters. Nei’s heterozygosity analysis revealed 0.265 ± 0.18 variability within the population. The high genetic variability present within the natural population of Daba ecorace of A. mylitta is indicative of their adaptational strategy in nature and have much importance for in situ conservation as well as utilization in breeding programs.