BIOECOLOGY OF RAILY – AN ENDEMIC SAL BASED ECORACE OF

ANTHERAEA MYLITTA DRURY IN BASTAR (CHHATTISGARH)

INTRODUCTION:

Tropical tasar silkworm Antheraea mylitta D. is an extremely versatile insect

species and has encountered a wide range of geoclimatic conditions as is evident from its

distribution. Different ecotypes of A. mylitta isolated geographically over century have

adapted to a particular ecological nature.

Chhattisgarh is the second largest producer of tasar silk and bulk of its production,

more than 100 MT comes from the nature grown cocoons of the ecorace Raily from

Bastar in Chhattisgarh.

Raily, an ecorace of wild tasar silkworm Antheraea mylitta D. is endemic to

Bastar District (Chhattisgarh) which feeds primarily on Shorea robusta (Sal). The Sal

grown larvae are robust and the cocoons are compact & tough with rich in silk content.

The pupal diapause results in one or two life cycle a year. About five to eight crore Raily

cocoons are collected by the tribal of Bastar division from different ecopockets. About

80% cocoons are collected during Bhadon (July-Aug.) and come to markets during 15 th

August to 30th September, the peak being in 1st fortnight of September. These cocoons

are big in size and superior to that of Chaithi cocoons. About 20% cocoons come to the

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markets during 15th February and 15th April, peak being March, hence called Chaithi

cocoons, which are small in size and comparatively in low quality.

About 5 to 8 crores Raily cocoons are collected by the tribal of Bastar division

after adopting insitu conservation strategies but in recent past the production has declined

due to its over exploitation.

Production figures of nature grown Raily cocoons in Bastar during past 24 years

reveals the growth rate to the tune of 5.64% per annum but the rate of exploitation is

more than the rate of natural multiplication. About 40,000 tribals are engaged in

collection of Raily ecorace from forests. (Yadav et al 2010)

Continuous collection of nature grown cocoons of ecorace Raily without caring

for the population dynamics and survival, often results in over exploitation of the natural

resources for commercial/economic gains by the mankind, pushing the species to the

threshold limits of extinction. Besides it is one of the minor forest produce on which

thousand of tribals depend on their livelihood. From both these points, there is a need to

take measures not only to increase their number in nature but also introduce the ecorace

in other areas where the primary food plant sal (Shorea robusta L.) is available in

considerable density in the forest patches.

Conservation strategies are required to be adopted as a long term measures in

order to reduce the loss of valuable natural populations of Antheraea mylitta D. and its

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potential utilities. The interactions of silkworms with external factors determines their

behavioural activities like relationship between silkworm and its food plants, growth and

developments, defensive adaptations, survivability etc. Various ecological factors such as

quality of food, temperature, humidity, light, altitudes and geographical locations etc.

play an important role in determining various activities in tasar silkworms. The essential

ecological factors are needed to provide quite conducive and ideal environment for the

proper adjustment and acclimatization of tasar silkworm under domesticated conditions.

Hence, it is essential to have the thorough knowledge on bioecology and

population dynamics in order to stabilize the crop. There is lot of scopes of increasing the

production of ecorace Raily in Bastar (Chhattisgarh). Attempt will be made to study the

bioecology of Raily ecorace in its natural habitat to understand various related aspects

with the changing environmental parameters.

REVIEW OF LITERATURE

Considerable preliminary studies have been conducted to know the habitat and

habit of Raily ecorace. Survey conducted in different forest ranges of Bastar division

revealed that the maximum availability of Raily cocoons on food plant Shorea robusta

with a poor survivality in nature. Quality of the cocoons has been reported to be superior

during Aug.-Sept. crop than the Feb-March crop. (Annual Report 1988-89). Seven

ecopockets of Bastar viz. Darbha, Nangoor, Tokapal, Tongpal, Kondagaon, Narayanpur

and Geedam were reported to be identified as the potential areas for the availability of

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Raily cocoons in Bastar. Cocoons of Nangoor ecopocket has been reported to be superior

in economic characters. During survey and collection 36.67% of the cocoons were

collected from Shorea robusta 30.0 % from Terminalia tomentosa and 33.3% from

T.arjuna. The cocoons collected from Shorea robusta were reported to be better than

these collected from T. arjuna and T. tomentosa (Annual report, 1989-90). Economic

characters of the cocoons of first crop have been reported to be superior to the cocoons of

second crop (Annual report, 1990-91). Morphometric characters of the adult (moth) have

also been studied (Annual Report, 1991-92 to 1993-94). Nangoor, Darbha, Tokapal and

Tongpal are reported to be highly potential zones which accounted for 70-80% of the

total natural production (Annual Report, 1991-92, 1992-93 and 1993-94).

Studies on preservation of seed cocoons of Raily ecorace conducted from January

to June have been reported to result in the minimum pupal mortality in the lots preserved

underground cellar and maximum in outdoor followed by indoor conditions. It is also

reported that unseasonal emergence is lowest under outdoor in comparison to cellar and

indoor condition (Annual Report, 1989-90 to 1994-95). Preservation and behavioural

studies indicated performance of cocoons processed in insitu is better than those

preserved in exsitu conditions in terms of effective survival of cocoons, coupling and egg

layings (1994-95 to 2000-01).

Studies on grainage behaviour of Raily ecorace A.mylitta D. have been conducted

(Annual Report 1987-88 to 2000-01). It has been reported that the moth emergence starts

from the month of March and extends up to July with a peak emergence during the month

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of May (when the temperature was high) during first season. During second season the

emergence starts both in indoor and outdoor from the month of October and continues

erratically upto February (Annual Report, 1987-88). Emergence percentage of the moths

have been reported to be maximum (84.35%) under indoor conditions during first

preservation season with a minimum of coupling percentage (3.85%), whereas the

cocoons preserved in outdoor hanging on the plant without cover and covered with nylon

net resulted in emergence of 51.09 and 51.7% moths and coupling percentage of 60.33%

and 46.53%. Continuous emergence have been reported from March to June period

During Second season maximum emergence (64.21%) has been recorded

in indoor conditions with a coupling percentage of 20.18%. Under outdoor condition

during second season emergence have been reported to range between 13.33 - 55.82%

with the coupling percentage of 12.22 to 27.50 %. It is further reported that while the

emergence under indoor conditions was observed between September and January, the

same was found to range between September and December in outdoor condition.

(Annual Report, 1988-89). Better performance in respect of emergence, mating and egg

laying in Raily ecorace in Bastar under outdoor condition have been reported in

comparison to indoor condition (Annual Report 1989-90 to 2000-01).

Optimum periods of brushing for raising of successful silkworm crop of

Raily ecorace has been reported to be 2nd/3rd week of June and first fortnight of October

for Ist and IInd crop respectively in Bastar (Annual Report 1989-90 to 1991-92).

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The rearings conducted on different food plants revealed that the

survivality of Raily silkworm larvae is more on Terminalia tomentosa followed by

T.arjuna and Shorea robusta, however the silk ratio was reported to be higher in the

cocoon fed with leaves of Shorea robusta than the Terminalia plants. (Annual Report

1989-90 to 1996-97 etc.)

To explore the possibility for minimising mortality due to bacteriosis and virosis,

the use of Tasar keet Oushadh (TKO) and sodium hypochlorite could not yield any

significant result in respect of rearing performance of Raily ecorace.(1991-92, 92-93, 93-

94). Rearing of Raily silkworm has been reported to have significantly better

performance under natural conditions than the control.(Annual Report 1996-97 to 2000-

01). Preliminary studies on demography of Raily ecorace in Bastar has been done

(Annual Report, 2000-01)

Significant improvement in the hybrid Raily x Daba over their parents in first crop

has been reported in respect of yield as well as survivality (Annual Report 1997-98). The

F1 hybrid has been reported to be stable under different climatic conditions which

consistently exhibited viability in mating compatibility, hatching, harmonious growth,

resistant to diseases, survival, silk yield, short larval period, uniform and reduced flimsy

cocoons, increase in production and productivity etc. (Annual Report, 2009-10)

Out of five methods for observing suitability of natural proliferation of Raily

ecorace releasing of eggs in Sal leaf cups have been reported to give better performance

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followed by releasing of chawkie worms, releasing of gravid moths, releasing of male

and female moths and releasing of seed cocoons respectively. (Annual Report 1997-98).

Raily has been reported to perform better in insitu conditions rather than in

captive conditions indicating that Raily is not amenable for handling because they loose

their original characters on interference and exhibit low survival (Annual Report 1998-99

to 2000-01)

Multiplication of Raily through Integrated Package of Rearing has been reported

to marginally enhancing effective rate of rearing in both the crops but the original

economic characters of nature grown Raily were not maintained (Annual Report 1998-99

to 2000-01).

Raily is more or less bivoltine in nature but a part of the population behaves as

univoltine. The first growth season starts from July and ends by September. The second

season starts from October and continues upto first week of January with overlapping of

generation. Later the pupa passes through the diapause stage upto June. Raily is

basically a wild ecorace found in nature and is not amenable for handling as such it is

very essential to know the ecology of Raily ecorace in great detail.

Project Period : 3 Years (2012-15)

Project Site : Forest of Bastar (Chhattisgarh)

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Budget : Rs. 10.56 lakhs

INPUTS

The studies will be carried out under natural conditions at Nangoor forest

ecopockets of Raily and under exsitu conditions at Sargipal Forest of Field Lab of

RTRS, Jagdalpur.

Under insitu, the observations will be made in nature grown population while under

exsitu conditions the observations will be made on population grown due to human

handling.

Scientists and technical Staff of RTRS, Jagdalpur will be associated with

conducting experiments on preservation, grainage and rearing, recording the

technical and meteorological data.

Estimated budget of the project is Rs. 10.56 lakhs.

OBJECTIVES:

To study the biology (Life cycle, grainage and rearing under insitu and exsitu

conditions etc.) and ecology (host plant interaction, pest and diseases,

environmental interaction (rainfall, temperature, relative humidity, photoperiod,

wind velocity etc.) in different ecopockets of ecorace Raily.

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METHODOLOGY:

I.1. To study on Raily ecorace under natural conditions, the population of this ecorace

from Nangoor ecopocket will be selected. Forest of RTRS Field Lab Sargipal will

be taken up for studies under exsitu conditions.

2. Life cycle, ecology, ethology and population dynamics of Raily ecorace will be

studied in its natural habitat.

3. Observations on the seasonal variations in the traits of population viz. eggs, larvae,

pupa, moths and cocoons will be recorded.

4. Recordings will be made on the abiotic associates viz. Temperature, Relative

humidity, Rainfall and Light etc.

5. Abiotic factors will be correlated with the biotic associates and the seasonal

variations in their breeding behavior.

6. The recording will be made on the availability of population on different food

plants and during different seasons,

7. Most favorable season will be identified based on the population structure.

8. Recordings will be made on reproductive potential such as emergence pattern,

coupling pattern, fecundity hatching etc. with complete life cycle from incubation

period of eggs to spinning and further breeding behaviour will be recorded in

natural environment.

9. Moth morphological traits and quantitative traits of cocoons from all seasons will

be analyzed to draw a normal distribution curve.

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10. Studies on the effect of biotic factors on the population of ecorace Raily

a. Food : Status of food plant namely sprouting/flowering/fruiting stage/leaf

shedding etc. will be recorded in order to correlate with population of

Raily.

b. Parasites/Predators/Pathogens: While sampling for collection of

population of Raily in natural habitat, associated parasites/ predators/

pathogens will also be collected and their parasitism and predators

tendencies will also be recorded over seasons.

II. Similarly, in exsitu conditions, a forest patch of Field Lab Sargipal will be selected

and the Raily cocoons will be infused. All the observations stated above will be

recorded so as to standardize rearing schedule of ecorace Raily in different seasons,

Treatments :

The experiment will be conducted with two locationsxthirteen

replicationsx2seasons = 52 combinations in total. The abiotic associates and biotic

associates germane to Raily will be recorded for each parameters/trait of the study. The

design is detailed here below:

Design : RBD

Locations/ Treatments : 02

Replications : 13

Season : 02

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Total combinations : 52

Error Df : 12

Sample size : 1000 cocoons in each replications

Period (3Years):2013, 2014, 2015

Seasons (Two):

March to August

September-December

Experimental Design

Locations/Treatment

L1R1 L1R2 L1R3 L1R4 L1R5 L1R6 L1R7 L1R8 L1R9 L1R10 L1R11 L1R12 L1R13

L2R13 L2R12 L2R11 L2R10 L2R9 L2R8 L2R7 L2R6 L2R5 L2R4 L2R3 L2R2 L2R1

Observations:

Sprouting behaviour of the food plant will be observed with reference to life

cycle, reproductive behaviour and productivity potential of Raily ecorace.

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Observations under insitu and exsitu conditions will be made on reproductive

potential such as % of pupal mortality, emergence, coupling, fecundity, hatching

of eggs and productive potential such as Effective rate of rearing/multiplication,

cocoon weight, shell weight, Silk ratio and absolute silk production etc.

Incidence of mortality of Raily silkworm due to diseases in relation to

meteorological factors will be observed. The harmful effects of different diseases

on the qualitative and quantitative characters will be investigated.

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4. Activities and duration : The following activities has to be repeated for 3 years from 2013-2015

Sl. No.

Activity No. and Description

Activity Description Period When Locations Who is responsible

1 Survey of Raily ecorace for distribution in Bastar

Survey of Raily ecorace for distribution in different forests and on food plants

2.5 Months

January – 1ST fortnight of March

Forest ranges in different districts of Bastar division and newly introduced areas of Chhattisgarh.

Scientific and Tech. Asst. of CSB and Field Off. of DOS, CG

2 Procurement of Seed cocoons during 1st

crop

a)Procurement of seed cocoons of ecorace Raily

b) Garlanding/preserva -tion of seed cocoons.

15 days

15 days

15-30 March

1-15 April

Insitu : Machkote forest rangeExsitu : Sargipal, Jagdalpur

-Do-

3 Recording of data for insitu and exsitu experiments

a) Recording of data on preservation & reproductive potential i.e. survivability, emergence, coupling, hatching, etc, and environmental parameters.b) Monitoring, recording availability of moth, eggs and worms in naturec) Monitoring , recording multiplication rate in insitu and exsitu conditionsd) Harvesting of cocoons under exsitu and insitu conditions, Assessment of productivity

2.5 months

1 month

1.5 months

15 days

April-may-1st fortnight of June

2nd fortnight June - 1st fortnight of July July-Aug (1st fortnight)

2nd fortnight of August

-Do-

-Do-

-Do-

-Do-

-Do-

-Do-

-Do-

-Do-

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parameters4 Procurement of Seed

cocoons during 2nd crop

a) Cocoons harvest of 1st crop of ecorace Raily will be preserved

15 days 1st fortnight of Sept.

-Do- -Do-

5 Recording of data for insitu and exsitu experiments

a) Recording of data on preservation & reproductive potential i.e. survivability, emergence, coupling, hatching etc, and environmental parameters.b) Monitoring, recording availability of moth, eggs and worms in naturec) Monitoring , recording multiplication rate in insitu and exsitu conditionsd) Harvesting of cocoons under exsitu and insitu conditions, Assessment of productivity

1 months

1 month

3 months

15 days

September

2nd fortnight of Sept to 1st fortnight of Oct.1st fortnight of Oct. to 2nd fortnight of Dec.

2nd fortnight of Dec.

-Do-

-Do-

-Do-

-Do-

-Do-

-Do-

-Do-

-Do-

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Activity table : The following activities has to be repeated for 3 years from 2013-2015

Sl Name of the Activity Sub- activities Symbol Preceding activity

Period When

1 Survey of Raily ecorace for distribution in Bastar

Survey of Raily ecorace for distribution in different forests and food plants

A 2.5 months

January – 1ST fortnight of March

2 Procurement of Seed cocoons during 1st

crop

a)Procurement of seed cocoons of ecorace Raily

b) Garlanding/preserva -tion of seed cocoons.

B

C

A

B

15 days

15 days

15-30 March

1-15 April

3 Recording of data for insitu and exsitu experiments

a) Recording of data on preservation & reproductive potential i.e. survivability, emergence, coupling, hatching, etc, and environmental parameters.b) Monitoring, recording availability of moth, eggs and worms in naturec) Monitoring , recording multiplication rate in insitu and exsitu conditionsd) Harvesting of cocoons under exsitu and insitu conditions, Assessment of productivity

D

E

F

G

C

D

E

F

2.5 months

1 month

1.5 months

15 days

April-may-1st fortnight of June

2nd fortnight June - 1st

fortnight of July

July-Aug (1st fortnight)

2nd fortnight of August

4 Procurement of Seed cocoons during 2nd

a) Cocoon harvest of 1st crop of ecorace Raily

H G 15 days 1st fortnight of Sept.

15

crop will be preserved 5 Recording of data for

insitu and exsitu experiments

a) Recording of data on preservation & reproductive potential i.e. survivability, emergence, coupling, hatching etc, and environmental parameters.b) Monitoring, recording availability of moth, eggs and worms in naturec) Monitoring , recording multiplication rate in insitu and exsitu conditionsd) Harvesting of cocoons under exsitu and insitu conditions, Assessment of productivity

I

J

K

L

H

I

J

K

1 months

1 month

3 months

15 days

September

2nd fortnight of Sept to 1st fortnight of Oct.

1st fortnight of Oct. to 1st fortnight of Dec.

2nd fortnight of Dec.

16

Start

A 10

B 2

C 2

D 10

E 4

F 6

G 2

H 2

I 4

J 4

K 12

L 2

Finish

Flow Chart

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ACTIVITY SLACK BAR CHART (ASBC)

AC

TIV

ITIE

S

L    

                    K

        J

        I

  H

  G

 

F

        E

E

      D

  C

  B

                      A                                                                        

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov DecTIME

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OUTPUT

1. Biology (Life cycle, reproductive and productivity potential of ecorace Raily

under insitu and exsitu conditions will be evaluated.

2. Ecology (host plant interaction, pest and diseases, environmental interaction

(rainfall, temperature, relative humidity, photoperiod, wind velocity etc.) in

different ecopockets of ecorace Raily will be defined.

3. Effect of changing environment on biology of ecorace Raily will be established.

Beneficiaries and Impacts :

Information generated will help

scientific community for planning

and executing the multiplication and

conservation strategies of nature

grown tasar ecoraces.

Increased rate of multiplication to

benefit the cocoon collectors

(Tribals) of the area for sustainable

use.

Outcome of the project will add to

increasing the production of Raily

ecorace in Bastar (Chhattisgarh)

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Draft Budget :

A. Non-Recurring ( e.g. equipments, accessories etc.)Sl. No. Item 1st Year 2nd Year 3rd Year Total1. Wooden cages 0 0 0 02. Nylon net 35000 0 0 350003. Equipment (Thermometer

and Hydrometer)30000 0 0 30000

4. One Laptop 0 0 05. One Digital Camera 25000 0 0 25000

Sub-Total A: 90000 0 0 90000

B. Recurring:

B1. Manpower:Sl. No.

Position Nos. Consolidated Emolument

1st Year 2nd Year 3rd Year Total

1 JRF/SRF/RA 0 0 0 0 0 02 HRA 0 0 0 0 0 03 CCA 0 0 0 0 0 04 Mandays/wages 730 354780 118260 118260 118260 354780

Sub-Total B1 730 354780 118260 118260 118260 354780

B2. Consumables:Sl. No. Item 1st Year 2nd Year 3rd Year Total1 Seed cocoons 156000 156000 156000 4680003 Miscellaneous( 50000 50000 50000 150000

Sub-Total B2 206000 206000 206000 618000

Other Items:Sl. Item 1st Year 2nd Year 3rd Year TotalB3 Travel 50000 50000 50000 150000B4 Contingency 0 0 0 0B5 Overhead charges 0 0 0 0

Sub-total (B1+B2+B3+B4+B5 etc) 464260 374260 374260 1212780Less Amount to be received from sale of Raily pierced cocoons (-) 156000

Total (Rs.) 10,56,780

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From:DR. G.P. MahobiaScientist-CRegional Tasar Research Station, 02-04-2012Kalipur Road, DharampuraJagdalpur (Chhattisgarh)494005Email: mahobiag@yahoo.com

To,The DirectorCTR&TIRanchi –

Sir,

Sub.:- Follow-up of 34th meeting of RAC- Submission of Concept note on proposed

project…Reg.

Ref.: Letter no. CTR&TI/PMEC/Tech-25/2011-12/11666 dated 30-01-2012

With reference to the subject cited above I wish to inform that I had a detailed discussions with Dr. K. Thangavelu after the Research Advisory Committee meeting held on 8 th

December, 2011 and as per the decision taken under the Agenda item No. 5(5), a conceptual note on proposed project entitled “Bioecology of Raily – An endemic Sal based ecorace of Antheraea mylitta D. in Bastar (Chhattisgarh)” has been prepared. I was advised by Dr K. Thangavelu to prepare the project as per the guidelines provided by him and send it first to the Director CTR&TI, Ranchi for making necessary correction which will be sent to him for final correction.

As such the proposed project is enclosed herewith (in hard and soft copies) for taking action from your end.

Your’s faithfully’

(DR. G.P. MAHOBIA)SCIENTIST-CRTRS, JAGDALPUR

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CONCEPT NOTES ON PROPOSED PROJECT

BIOECOLOGY OF RAILY – AN ENDEMIC SAL BASED ECORACE OF ANTHERAEA MYLITTA D. IN BASTAR (CHHATTISGARH)

Project Proposal Submitted to

CENTRAL SILK BOARD Ministry of Textiles (Government of India)

BTM Layout, Madivala Bangalore – 560 068

ByDr. G.P. Mahobia

Project InvestigatorDr. G.S. YadavCo-Investigator

Regional Tasar Research StationCENTRAL SILK BOARD

Ministry of Textiles (Government of India)Jagdalpur (Chhattisgarh) 494 005

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