How do earthworms reproduce?

Earthworm reproduction mode: hermaphroditic, allogamy, reproduction through the ring to produce cocoons, reproduction of the next generation.

Earthworm hermaphroditism, male reproductive organs in the 10th, 11th section of the posterior side, there are two pairs of spermary sac, each sac has a testis and a sperm funnel, through the diaphragm hole connected with the latter pair of seminal vesicles; two pairs of seminal vesicles located in the 11th and 12th sections, sperm cells produced in the testis, first enter the seminal vesicles development, after maturity, return to the spermary sac, from the sperm funnel through the vas deferens discharge. The two vas deferens, parallel in pairs after the 13th node, meet with the branches and main tubes of the prostate at the 18th node, and are discharged by the male genital aperture, which is on both sides of the ventral surface of the 18th node. The female reproductive organs have a pair of grape-like ovaries attached to the rear of the diaphragm in Section 12. The mature eggs fall into the coelom, pass through a pair of egg funnels in Section 13, pass through the shorter oviducts, and meet in Section 14, and are discharged by the female reproductive hole. There is only one female reproductive hole. In addition, there are 2 or 3 pairs of spermatheca in the 6 th to 9 th nodes, which are the places for receiving and storing allogeneic sperm and open on both sides of the abdominal internode groove in the 6 th to 9 th nodes.

Although earthworm is hermaphrodite, but because sexual cell matures period is different, reason still needs heterogamy fertilization. Male germ cells of earthworms mature first. After maturity, two earthworms want to mate. When mating, the accessory gonads secrete mucus, which makes the ventral surfaces of both sides adhere to each other and the head ends are divided into two sides. The male genital pore is opposite to the heterosexual fertilization sac pore, and semen is discharged from each male genital pore and enters the fertilization sac through the other's spermatheca pore. After exchanging semen, the two earthworms separate. When the eggs mature, the annulus secretes viscous substance, which solidifies outside the annulus and forms annular mucus tube (earthworm cocoon). The mature eggs are discharged from the female reproductive hole to the earthworm cocoon. When earthworms move backward in waves, their cocoons move forward gradually, and when they move to the spermatheca, sperm escape and fertilize in the cocoons. Earthworms continue to retreat, and finally the cocoon leaves the body, both ends closed and left in the soil. Each cocoon has 1 - 3 embryos and hatches within 2 - 3 weeks. If the environment is not suitable, it can be delayed until the spring of the following year.