Life is unique with a lot of variation that creates diversity, disparity, and strengthens the population. I love biology, the science of life, because it is amazing and almost tangible. Biology is the only science in which multiplication is the same thing as division. In fact, multiplication and division are both methods of reproduction. For example if a number of bacteria or cells multiply, indeed they divide too.
The compost worm or red wiggler has been studied extensively, particularly for its potential in vermiculture and vermicomposting. This is because it is easy to culture and its life cycle is relatively short with a fast growth rate. The life span can be up to 4 years. It takes 1.5 until 2 months for the compost worm to grow from egg to adult, and then it is ready to reproduce. Compost worms are homodynamous species, without a diapause in their life cycle. Hence, their reproduction activities, in favourable conditions at room temperature and 80% moisture, can be continuous throughout the year.
Like the other members of earthworms, compost worms (e.g. Eisenia fetida, E. andrei, E. hortensis) are hermaphrodite. The female and male reproductive organs are present in the same animals. Each compost worm has both the male part that produces sperms and the female part that produces eggs. A compost worm lays fertilized eggs called cocoons (compound eggs), and the cocoon production can be 1 cocoon per 2 days. One cocoon can produce on average 4 juveniles, with the viability up to 80%.
It has been reported that self-fertilization occurs in compost worms Eisenia fetida in about 10% of its reproduction activities. However, usually two compost worms are required to mate. The photo above is a very rare moment that I found recently after 20 years doing observation on compost worms. Three compost worms Eisenia andrei mate together. The photo can be zoomed to see details.
So, how amazing is the reproduction rate of the compost worms. Under the favourable conditions, it has been proven that Eisenia andrei population growth rate can follow an arithmetic-progression pattern every 3 month within a year such as 2, 4, 6, 8, 10 etc. In the laboratory with well maintained conditions, the population growth rate of the same species of compost worms can follow the geometric-progression pattern such as 2, 4, 8, 16, 32 etc.
Basically, compost worms can double their population within 2 months under optimum conditions. A compost worm is always in symbiosis with the beneficial soil microbes in its intestine. They can process the organic waste as the same amount as their body weight per day. Approximately 1 – 2% of the organic waste will be transferred as compost worms biomass, and 20 – 25% of the organic waste will be transferred as worm castings or vermicompost.
The gift from nature to compost worms can be used to process the large amount of organic wastes produced by the human population. The result will then become high quality compost termed worm castings or vermicompost to support the natural way of farming with less pesticides and chemical fertilizers.
– Bintoro Gunadi