Conceptual notes on bioecology of raily(revised)

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 15th
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
1

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
2

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
3

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
4

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).
5

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
6

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)
7

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.
8

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.
9

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
10

• Season : 02
• 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.
11

• 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.
12

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 range
Exsitu : 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 nature
c) Monitoring , recording
multiplication rate in
insitu and exsitu
conditions
d) 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-
13

parameters
cocoons during 2nd
crop
a) Cocoons harvest of 1st
crop of ecorace Raily
will be preserved
15 days 1st
fortnight of
Sept.
-Do- -Do-
insitu and exsitu
experiments
preservation &
coupling, hatching etc,
and environmental
parameters.
and worms in nature
insitu and exsitu
conditions
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-
14

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
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
insitu and exsitu
experiments
preservation &
coupling, hatching, etc,
and environmental
parameters.
and worms in nature
insitu and exsitu
conditions
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
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
insitu and exsitu
experiments
preservation &
coupling, hatching etc,
and environmental
parameters.
and worms in nature
insitu and exsitu
conditions
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
17

ACTIVITY SLACK BAR CHART (ASBC)
ACTIVITIES
L
K
J
I
H
G
F
E
E
D
C
B
A
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
TIME
18

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)
19

Draft Budget :
A. Non-Recurring ( e.g. equipments, accessories etc.)
Sl. No. Item 1st
Year 2nd
Year 3rd
Year Total
1. Wooden cages 0 0 0 0
2. Nylon net 35000 0 0 35000
3. Equipment (Thermometer
and Hydrometer)
30000 0 0 30000
4. One Laptop 0 0 0
5. One Digital Camera 25000 0 0 25000
Sub-Total A: 90000 0 0 90000
B. Recurring:
B1. Manpower:
Sl.
No.
Position Nos. Consolidate
d
Emolument
1st
Year 2nd
Year 3rd
Year Total
1 JRF/SRF/RA 0 0 0 0 0 0
2 HRA 0 0 0 0 0 0
3 CCA 0 0 0 0 0 0
4 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 Total
1 Seed cocoons 156000 156000 156000 468000
3 Miscellaneous( 50000 50000 50000 150000
Sub-Total B2 206000 206000 206000 618000
Other Items:
Sl. Item 1st
Year 2nd
Year 3rd
Year Total
B3 Travel 50000 50000 50000 150000
B4 Contingency 0 0 0 0
B5 Overhead charges 0 0 0 0
Sub-total (B1+B2+B3+B4+B5 etc) 464260 374260 374260 1212780
Less Amount to be received from sale of Raily pierced cocoons (-) 156000
Total (Rs.) 10,56,780
20

From:
DR. G.P. Mahobia
Scientist-C
Regional Tasar Research Station, 02-04-2012
Kalipur Road, Dharampura
Jagdalpur (Chhattisgarh)
494005
Email: mahobiag@yahoo.com
To,
The Director
CTR&TI
Ranchi –
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 8th
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-C
RTRS, JAGDALPUR
21

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
By
Dr. G.P. Mahobia
Project Investigator
Dr. G.S. Yadav
Co-Investigator
Regional Tasar Research Station
CENTRAL SILK BOARD
Ministry of Textiles (Government of India)
Jagdalpur (Chhattisgarh) 494 005
22

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Conceptual notes on bioecology of raily(revised)

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