Question

In earthworm
A. Ovaries are larger than testes
B. Testes are larger than ovaries
C. Both are equal
D. Right testes are larger than ovaries

Answer 1

Hint: Earthworms are hermaphrodites and have both male and female organs in their bodies. These organs are located in different segments. Female organs have ovaries, oviducts and spermatheca and the male organs include testes, testes sac, seminal vesicles and spermatic fluids.

Complete answer:
Earthworms are well known as farmer’s friends. They are reddish brown terrestrial in habitat and found in the upper layers of soil. Lumbricus and Pheretima are the common Indian earthworm species. Their body is divided into segments. Being hermaphrodites they have both male and female organs in their body.
- Male reproductive system
Two pairs of testes are present in the 10th and 11th segment, vasa deferentia extends to the 18th segment where it joins the prostatic duct. In the 17th and 19th segment two pairs of accessory ducts are present. A common prostatic and spermatic duct (vasa deferentia) opens to the outside with the help of a male genital pore present on the ventro-lateral side of the 18th segment. 4 pairs of spermatheca are present in each segment from 6th to 9th segment, they receive and collect sperms for copulation.
- Female reproductive system
One pair of ovaries is attached to the 12th and 13th segment, which extend into ovarian funnels that open into oviducts, the ovarian funnels join and open on the ventral side as a genital pore in the 14th segment. Ovaries are larger in sizes compared to the testes.
Thus, the right option is A.

Additional information:
- Though earthworms are hermaphrodites they can both copulate and cross fertilize and this
happens mostly during the rainy season.
- During copulation two earthworms attach by their ventral side to exchange the sperms.
- Spermatheca are flask shaped with ampulla being their main body that stores sperms in a
small lobe called diverticulum.

Note: During copulation both worms exchange their sperms and both develop cocoons after fertilisation that consists of several fertilised eggs. These cocoons are laid on the soil surface or below the soil surfaces depending upon the season.