Research Team

Understanding Composting Earthworms for Efficient Vermicomposting

July 27, 2023

Earthworm composting plays a crucial role, and to achieve it, we need specific earthworms suitable for the task.

The goal is to use these composting earthworms to process organic waste and create vermicompost. The ideal scenario is if these earthworms can directly live in the organic waste and feed on it without the need to reside in the soil. Three ecological types of earthworms exist: epigeic, endogeic, and anecic, each with distinct feeding habits. Most earthworms found in the wild belong to the endogeic category, which primarily feed on detritus and soil. Therefore, using these wild-collected earthworms for vermicomposting, whether for kitchen waste or large-scale organic waste like animal manure, is impractical.

From an ecological and feeding perspective, epigeic herbivorous earthworms are the most suitable group for vermicomposting. These earthworms inhabit the surface layer of decomposed organic matter, such as dried leaves and plant debris. For efficient processing of organic waste, it's best to select epigeic herbivorous species with short life cycles, rapid reproduction, adaptability to various environments, and the ability to be densely cultured.

Globally, out of over 6000 earthworm species, only less than ten are extensively mass-cultivated for processing organic waste, and they are collectively known as "composting earthworms."

Here's a list of common international composting earthworms:

Eisenia fetida:

  • Red worm
  • Manure worm
  • Branding worm
  • Tiger worm
  • Panfish worm
  • Trout worm
  • Red wiggler

Eisenia andrei:

  • Red Worm
  • Manure worm
  • Panfish worm
  • Trout worm
  • Red wiggler

Dendrobaena hortensis:

  • European nightcrawler

Eudrilus eugeniae:

  • African nightcrawler

Perionyx excavatus:

  • Blue worm
  • Indian blue
  • Malaysia blue

Dendrodrilus rubidus:

  • Red wiggler
  • Wiggier
  • Pink worm
  • Jumbo red worm
  • Jumping red wiggler
  • Trout worm
  • Jumper
  • Red wiggler worm
  • Red trout worm

Lumbricus rubellus:

  • Red earthworm
  • Red marshworm
  • Angle worm
  • Leaf worm
  • Red wiggier

A Comparison of European Red Worm, African Nightcrawler, and Indian Blue Worm

European Red Worm:

The European Red Worm, measuring less than 10 centimeters in length and slender, derives its name from its dark red or bright red appearance. It features yellow secretions, making the posterior part of its body exhibit a yellow hue, more pronounced near the tail. This characteristic aids in distinguishing its juveniles from those of the other composting worms.

However, identifying worm species based on size, color, and patterns is only a reference point. For a definite determination, one must focus on the appearance of annular bands and the morphological structure of genital pores on the ventral side. Among the three composting worms, the European Red Worm is distinguished by its annular band pattern, extending from the 25th to the 30th segment, appearing as a swollen light red or light-colored band.

Fortunately, counting segments is unnecessary to identify the European Red Worm. Its annular bands are located far back, around the 25th segment to the 30-something segment, distinct from the other two composting worms whose bands are near the 15th segment. Thus, differentiating the European Red Worm becomes effortless by checking for the annular band around the 15th or 25th segment.

Life Cycle and Productivity of European Red Worm:

To adapt to risks in the surface layer and drastic soil changes, the European Red Worm has a short life cycle, rapid growth, and high reproductive capacity. Maturing in just 21 to 28 days after hatching, it can lay egg capsules two days after mating, producing one every two to three days under suitable conditions. Each capsule takes 18 to 26 days to hatch, with a hatching rate of 70% to 90%. Notably, each capsule typically contains 2.5 to 3.8 young worms, with records of up to 12 juveniles in rare cases. This allows for a new generation every 45 to 51 days.

Remarkably, the European Red Worm's average lifespan is approximately 600 days, with some individuals living up to four and a half to five years in a controlled environment. This adaptability has led the European Red Worm to thrive worldwide, aiding in waste management caused by human activities. However, it prefers a temperate climate, tolerating temperatures from 0°C to 35°C, with an optimum at 25°C. Survival becomes challenging above 35°C, especially in direct sunlight during summer.

African Nightcrawler:

The African Nightcrawler is popularly referred to as ANC in foreign composting worm information, reflecting its recognition and popularity. Its name originates from Africa, where it is also known as the (Nightcrawler) due to its nocturnal surface activity, making it demand more attention in farming management than the European Red Worm.

The African Nightcrawler is the largest of the three composting worms, growing 9 to 19 centimeters long, nearly twice the size of the European Red Worm. Favorable conditions can lead to lengths of 25 to 40 centimeters, with a gradually thinner and flatter body towards the tail, distinguishing it from the plump front end.

Its color ranges from reddish-brown, bluish-purple, to yellowish hues, with a lighter tail end creating a translucent appearance. Moreover, the worm displays vibrant blue-purple iridescence on its body, more prominent in the front.

To differentiate the African Nightcrawler, attention should be on its annular band position and morphology. Unlike the European Red Worm, the African Nightcrawler's bands start between the 13th and 15th segments, ending at the 18th segment. Additionally, the male pores have a unique hook-shaped penis during mating, rare among worm species.

The African Nightcrawler prefers temperatures of 16°C to 32°C, with an optimum at 25°C. Growth and reproduction efficiency decrease at temperatures over 30°C. It does not handle extreme heat well and cannot survive temperatures below 12°C or above 30°C for juveniles. The ideal humidity range is 80%, with levels between 70% and 85% being suitable.

Its life cycle is relatively short, typically living one to three years, but juveniles mature quickly in 35 to 50 days. Under favorable conditions, it lays one egg capsule per day or three capsules every two days, with a 75% to 85% hatching rate, typically containing one juvenile worm.

Indian Blue Worm:

The Indian Blue Worm is colloquially known by this name due to its English common name, "Indian blue." It is important to note that this worm's name originates from its initial discovery in India and not because it is an exclusively exotic species. Its native range spans from South Asia (India and Bangladesh) to Southeast Asia (Peninsular Malaysia, the Philippines, and Indonesia), where it is also known as the "Malaysian blue."

The Indian Blue Worm's size is generally similar to the European Red Worm, around 10 centimeters, but can grow longer. Its appearance is somewhat "slender" or "thin and long," distinguishing it from the stout and round-headed European Red Worm.

Its color varies significantly, from deep brown to purple, red, and even yellowish-brown, making color unreliable for identification. The Indian Blue Worm has an evident dorsal line along its back, but this may be hard to see in individuals with dark coloration.

Contrary to its name, the "blue" in Indian Blue Worm refers to iridescent blue-purple reflections on its body surface, but this feature is not consistent. The Indian Blue Worm's clitellum is a light-colored region between the 13th and 17th segments, aiding in its identification.

Is the Indian Blue Worm Special?

The Indian Blue Worm is well-suited for composting kitchen waste in tropical countries due to its adaptability to warm and humid environments. Its short life cycle, rapid growth, and high reproductive capacity make it a valuable composting worm, similar to the European Red Worm.

Despite its benefits, the Indian Blue Worm can be active and prone to escaping. However, it is less notorious for escaping compared to the African Nightcrawler.

Conclusion

Each composting worm, the European Red Worm, African Nightcrawler, and Indian Blue Worm, possesses unique characteristics and advantages. Understanding their differences and specific needs is essential when selecting the right composting worm for a particular environment and purpose. Regardless of the species chosen, composting with worms offers an environmentally friendly and efficient method to recycle organic waste, creating nutrient-rich compost for plants and gardens.

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