Table of Contents
Last Updated: January 28, 2026
Estimated reading time: ~8 minutes
Word count: 1,480
Wild silkmoths form the backbone of the non-mulberry sericulture industry, offering significant economic opportunities through the production of Tasar, Eri, and Muga silks. This comprehensive study investigates the biosystematics of Saturniid moths in Western Maharashtra, identifying nine new subspecies of Antheraea mylitta and establishing effective rearing protocols. By optimizing indoor rearing techniques and identifying alternative host plants like Terminalia catappa, this research provides a framework for enhancing wild silk production and conserving biodiversity.
Key Takeaways:
- Identification of nine new subspecies of Antheraea mylitta based on morphological and genital characters.
- Detailed life cycle analysis of Attacus atlas, Actias selene, and A. mylitta kolhapurensis.
- Confirmation of Terminalia catappa (Indian Almond) as a viable host plant for indoor rearing.
- Achievement of a 45% rearing success rate for A. mylitta kolhapurensis under laboratory conditions.
- Morphometric characterization of cocoons to assess commercial rearing potential.
Taxonomy and New Subspecies of Antheraea
The genus Antheraea, widely distributed across the tropical belts of India, is crucial for Tasar silk production. Taxonomical clarity is essential for breeding programs and conservation. Through extensive surveys in the districts of Kolhapur, Sangli, Satara, and Pune, the research isolated and characterized distinct populations of wild silkmoths. The study utilized detailed morphological analysis, particularly of the male genitalia (uncus, valva, and aedeagus) and wing venation, to distinguish between subspecies.
“The male genitalia consist of VII, VIII, IX and X abdominal tergites and sternites… the IX and X segments are greatly modified and act as gonosomites.” (Kavane, 2010, p. 70)
The research led to the identification of nine new subspecies of Antheraea mylitta Drury. These subspecies show variations in cocoon weight, shell ratio, and distinct genital features, separating them from previously known ecoraces like Daba or Sukinda. For instance, A. mylitta kolhapurensis is characterized by a specific forewing curvature and genital structure. Accurate identification allows sericulturists to select specific ecotypes that are better adapted to local climatic conditions, potentially improving silk yield and disease resistance.
Student Note: In insect taxonomy, the structure of the male genitalia is often the most reliable character for distinguishing between closely related species or subspecies due to the “lock and key” hypothesis of reproductive isolation.
Fig: Key morphological differences among selected new Antheraea mylitta subspecies
| Subspecies Name | Distinguishing Genital Feature | Forewing Character | Host Plant Association |
|---|---|---|---|
| A. mylitta indica | Aedeagus knife-shaped, black banded; Saccus rounded | Antero-lateral edge blunt | Ziziphus jujuba |
| A. mylitta jujubi | Dorsolateral lobe with 3 long spines; Aedeagus broader | Hook-like curvature | Ziziphus jujuba |
| A. mylitta arjuni | Saccus very short; Aedeagus hockey-stick shaped | Antero-lateral edge blunt | Terminalia arjuna |
| A. mylitta kolhapurensis | Saccus longer/rounded; Harpes broad & pointed | Forewing not ‘S’ shaped | Terminalia catappa |
| A. mylitta sahyadricus | Saccus very narrow; Dorsolateral spines long | Forewing acute/pointed | Terminalia tomentosa |
Professor’s Insight: When identifying these moths in the field, look for the hyaline (transparent) spots on the wings; their shape (oval vs. circular) is a quick diagnostic trait before performing complex genital dissections.
Biology of Atlas and Moon Moths
Understanding the life cycle of wild silkmoths is fundamental to their domestication and conservation. The study provided a detailed biological account of Attacus atlas (Atlas moth) and Actias selene (Moon moth), alongside the new A. mylitta subspecies. These Saturniids are holometabolous, passing through egg, larva, pupa, and adult stages. The research highlighted that larval duration and survival rates are heavily influenced by the host plant species and environmental conditions like temperature and humidity.
“In the present study, biology of 3 silkworms namely A.atlas, A.selene & A.mylitta sub.sp. kolhapurensis have been studied and result indicated that all 3 species of silkworm complete their life cycle in relatively short period than that of previously reported.” (Kavane, 2010, p. 133)
Attacus atlas, one of the largest moths in the world, was successfully reared on Ficus carica (Fig). The larvae of A. atlas are distinct, possessing fleshy tubercles covered in a white waxy substance. Actias selene, known for its trailing hindwing tails, prefers Terminalia species. The study recorded specific developmental timelines essential for planning grainage (egg production) operations. Shortened life cycles in laboratory conditions suggest that controlled environments can accelerate breeding cycles for commercial purposes.
Student Note: The term voltinism refers to the number of generations an organism completes in a year; A. selene typically exhibits trivoltinism (three generations) in controlled laboratory settings.
Fig: Rearing requirements for Attacus atlas (Atlas Moth)
| Instar Stage | Duration (Days) | Feeding Frequency (Per Day) | Temperature (°C) | Humidity (%) | Bed Size (Sq ft) |
|---|---|---|---|---|---|
| 1st Instar | 5 | 1 | 28 – 30 | 75 | 1 |
| 2nd Instar | 4.5 | 2 | 28 – 30 | 75 | 3 |
| 3rd Instar | 4 | 2 | 28 – 30 | 80 | 6 |
| 4th Instar | 6 | 2 | 28 – 30 | 80 | 10 |
| 5th Instar | 7 | 2 | 28 – 30 | 80 | 16 |
Professor’s Insight: Note the high humidity requirement (75-80%); wild Saturniids are highly sensitive to desiccation, so maintaining humidity is critical for successful molting and survival.
Rearing Potential and Cocoon Characterization
The commercial viability of wild silkmoths depends on their rearing performance and cocoon quality. A major constraint in wild sericulture is the high mortality rate of larvae outdoors due to pests and weather. This study evaluated the potential of indoor rearing using plastic boxes and galvanized iron trays. The focus was on A. mylitta kolhapurensis, which demonstrated a promising rearing success rate of 45% when fed on Terminalia catappa leaves. This is a significant improvement over traditional methods which often see success rates as low as 30%.
“The silkworms were adopted in indoor rearing technique by preparing no peduncle which is normally spun by the worms in outdoor rearing is outstanding feature of the success of indoor rearing technique.” (Kavane, 2010, p. 132)
Cocoon characterization involves measuring weight, shell ratio, and silk denier. The study found that T. catappa supports robust cocoon formation, comparable to primary food plants like T. arjuna. The ability to rear these silkworms indoors on locally available host plants like T. catappa (Desi Badam) opens new avenues for sericulture in non-traditional areas, reducing pressure on forest-based primary host plants.
Student Note: The Shell Ratio (SR%) is a critical commercial parameter calculated as (Weight of Shell / Weight of Whole Cocoon) × 100; a higher SR% indicates more silk content per cocoon.
Fig: Cocoon characterization of A. mylitta kolhapurensis on different host plants
| Host Plant | Cocoon Weight (g) | Shell Weight (g) | Shell Ratio (%) | Shell Thickness (mm) |
|---|---|---|---|---|
| Terminalia catappa | 10.42 | 1.09 | 10.46 | 0.28 |
| Terminalia arjuna | 11.32 | 1.32 | 11.66 | 0.32 |
| Terminalia tomentosa | 11.42 | 1.56 | 13.66 | 0.33 |
Professor’s Insight: While T. tomentosa yields the highest shell ratio, T. catappa is a viable alternative for urban or indoor rearing where forest species might not be available.
Real-Life Applications
- Sustainable Tribal Livelihoods: Implementing indoor rearing techniques for A. mylitta can stabilize income for tribal populations in Maharashtra by reducing crop loss from outdoor predators.
- Biodiversity Conservation: Identifying and cataloging local subspecies like A. mylitta sahyadricus helps in creating specific conservation strategies for the Western Ghats biodiversity hotspot.
- Alternative Silk Industry: Commercializing the silk of Attacus atlas (Fagara silk) and Actias selene can diversify the Indian silk market beyond traditional Tasar and Mulberry.
- Forestry Management: Utilizing Terminalia catappa as a tertiary food plant allows for sericulture in agro-forestry setups without depleting primary forest reserves of T. tomentosa.
- Bioprospecting: The unique properties of wild silk, such as UV protection and high tensile strength, have applications in medical textiles and biomaterials.
Why this matters: These applications bridge the gap between academic taxonomy and practical economic development, turning biological diversity into a sustainable resource.
Key Takeaways
- Taxonomic Diversity: Western Maharashtra harbors significant diversity of Antheraea mylitta, with nine distinct subspecies identified.
- Host Plant Flexibility: Terminalia catappa is confirmed as a successful food plant for A. mylitta kolhapurensis, facilitating indoor rearing.
- Indoor Rearing Viability: Indoor techniques can achieve up to 45% rearing success, significantly higher than traditional outdoor methods.
- Life Cycle Efficiency: Local climatic conditions allow Attacus atlas and Actias selene to complete life cycles in 35-45 days, supporting multiple crops per year.
- Genital Identification: Morphological study of male genitalia is the definitive method for distinguishing between wild silkmoth subspecies.
- Economic Potential: The high shell ratio of wild cocoons indicates strong potential for textile production if mass-rearing protocols are adopted.
MCQs
1. Which part of the male genitalia is most critical for distinguishing subspecies of Antheraea mylitta?
A) Antennae
B) Uncus and Harpes
C) Thoracic legs
D) Labial palps
Correct Answer: B
Difficulty: Moderate
Explanation: The thesis emphasizes that the structure of the genitalia, specifically the uncus, saccus, and harpes, provides the specific characters needed to separate subspecies.
2. Which host plant was found to support a 45% rearing success rate for A. mylitta kolhapurensis in laboratory conditions?
A) Ficus carica
B) Ziziphus jujuba
C) Terminalia catappa
D) Ricinus communis
Correct Answer: C
Difficulty: Easy
*Explanation: The results section highlights *Terminalia catappa* as a successful tertiary food plant for indoor rearing of this specific subspecies.*
3. What is the approximate shell ratio of A. mylitta kolhapurensis cocoons when reared on Terminalia tomentosa?
A) 10.46%
B) 11.66%
C) 13.66%
D) 19.32%
Correct Answer: C
Difficulty: Challenging
*Explanation: According to the cocoon characterization data (Table 6), the shell ratio on *T. tomentosa* is 13.66%, which is higher than on other plants.*
4. The “Fagara” silk is produced by which wild silkmoth species?
A) Antheraea mylitta
B) Actias selene
C) Attacus atlas
D) Samia cynthia
Correct Answer: C
Difficulty: Moderate
*Explanation: The discussion mentions that *Attacus atlas* silk is commercially known as Fagara silk and is noted for its durability.*
FAQs
Q: What is the primary advantage of indoor rearing for wild silkmoths?
A: Indoor rearing significantly reduces larval mortality caused by natural predators (birds, insects) and environmental fluctuations, increasing the effective rate of rearing (ERR) from ~30% to over 45%.
Q: Can Attacus atlas be reared commercially in India?
A: Yes, the thesis suggests that Attacus atlas has commercial potential (“Fagara” silk) and can be reared on Ficus carica, though standard mass-rearing techniques are still being developed.
Q: What is the difference between Antheraea mylitta and A. mylitta kolhapurensis?
A: A. mylitta kolhapurensis is a newly described subspecies found in the Kolhapur region. It differs in specific genital structures (rounded saccus, broad harpes) and has a distinct forewing curvature compared to the nominal species.
Q: Why is Terminalia catappa important for sericulture?
A: Terminalia catappa (Indian Almond) is a widely available tree that serves as an effective alternative host plant, allowing for sericulture activities in areas where primary forest hosts like T. tomentosa are scarce.
Q: How do researchers identify different subspecies of silkmoths?
A: Researchers use biosystematics, which includes analyzing external morphology (wing patterns, antennae) and internal anatomy (specifically male genitalia), as well as biological traits like cocoon characteristics and host plant preference.
Lab / Practical Note
Genitalia Preparation: To study the genitalia of wild silkmoths for identification, boil the abdominal tip (segments VII-X) in 10% KOH solution for 30 minutes. This dissolves the soft tissues (muscles/fat), leaving the chitinous genital structures intact. Wash in distilled water, dehydrate in alcohol series, and mount in Canada Balsam for microscopic observation. Safety: KOH is caustic; wear gloves and eye protection.
External Resources
- Central Silk Board, India – Official body for sericulture research and development in India.
- Global Biodiversity Information Facility (GBIF) – Database for species occurrence records and taxonomy.
Sources & Citations
Kavane, R. P. (2010). Biosystematics of wild silkmoths from Western Maharashtra. (Doctoral dissertation, Shivaji University, Kolhapur). 1-304.
Source Note: The PDF provided contained the full thesis text, including taxonomy, biology, and rearing data. Tables 1-6 and Plates I-XXI were used to verify rearing requirements and morphological descriptions.
Correction Invitation: If you are the author of this thesis and wish to provide updates or corrections to this summary, please contact us at contact@professorofzoology.com.
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