The earthworms are hermaphrodites. They will produce eggs and sperm within the same body. they can't reproduce by self-fertilization. the reason is that the male and therefore the female sex organs don't mature at an equivalent time.

Why earthworms do not self-fertilize?

In fact, most species do not self-fertilize, and many are physically incapable of self-fertilization. ... The reproductive organs of earthworms are positioned at different ends of their bodies, so that fertilization of the eggs is only possible when the worms are aligned in opposite directions.

Who do earthworms do not self-fertilize?

Hermaphrodites are organisms that have both male and female reproductive organs. Examples of these are sponges, sea anemones, tapeworms, snails, and earthworms. They are either sedentary or mobile but do not move around enough to allow them to self-fertilize.