Annelids are all manner of earthworms, leeches and marine worms. Their reproductive systems are complex and need precision in order to successfully reproduce.
Leeches
Leeches are hermaphrodites: they are both male and female. reproduction varies from leech to leech, but most leeches use a penis and vagina for reproduction. all leeches have testisacs which produce sperm. the number of pairs can vary from leech to leech. The leech's ovisacs always consist of one pair: however, they can be spherical or tubular depending on the species of leech. Leeches fertilize internally; a spermatophore in implanted into the mate's body with a penis. The sperm fertilizes the eggs, and soon after, the eggs are placed inside cocoons, which are either attached to a surface, or n the leech's actual body.
Here, the leech Helobdella papillornata, has its cocoons on its body
Leeches
Leeches are hermaphrodites: they are both male and female. reproduction varies from leech to leech, but most leeches use a penis and vagina for reproduction. all leeches have testisacs which produce sperm. the number of pairs can vary from leech to leech. The leech's ovisacs always consist of one pair: however, they can be spherical or tubular depending on the species of leech. Leeches fertilize internally; a spermatophore in implanted into the mate's body with a penis. The sperm fertilizes the eggs, and soon after, the eggs are placed inside cocoons, which are either attached to a surface, or n the leech's actual body.
Here, the leech Helobdella papillornata, has its cocoons on its body
Earthworms
Earth worms are also hermaphrodites. when mating, the worms connect facing the opposite ways. During mating, the male genitalia area is raised int a papillae and inserted into spermathecal pores and the sperm is transferred and stored in the spermathecae. afterwards, the worms separate. The worms form a mucous ring around a segment called the clitellum. the ring moves across the worm's body and gathers sperm and eggs from male and female pores. the ring is cast off, and it hardens into a cocoon. The fertilization occurs in the cocoon. only one embryo survives: the others wither away. soon the juvenile worm breaks out of the cocoon and leaves.
Two earthworms in the mating process.
Earth worms are also hermaphrodites. when mating, the worms connect facing the opposite ways. During mating, the male genitalia area is raised int a papillae and inserted into spermathecal pores and the sperm is transferred and stored in the spermathecae. afterwards, the worms separate. The worms form a mucous ring around a segment called the clitellum. the ring moves across the worm's body and gathers sperm and eggs from male and female pores. the ring is cast off, and it hardens into a cocoon. The fertilization occurs in the cocoon. only one embryo survives: the others wither away. soon the juvenile worm breaks out of the cocoon and leaves.
Two earthworms in the mating process.
Rag-worms
Rag-worms mate when the body swells up with eggs or sperm. Unlike many other annelids, most rag-worms have a gender, only some are hermaphrodites. The female worm leaves its burrow on the marine floor and goes to the surface, where it releases its eggs; however, it will die soon after. The male goes to the surface and fertilizes the eggs with sperm. The eggs hatch into spherical larvae, which then find a place to mature to adulthood. Some rag-worms are hermaphrodites and have the extremely rare ability to fertilize their own eggs.
Two rag-worms mating
Rag-worms mate when the body swells up with eggs or sperm. Unlike many other annelids, most rag-worms have a gender, only some are hermaphrodites. The female worm leaves its burrow on the marine floor and goes to the surface, where it releases its eggs; however, it will die soon after. The male goes to the surface and fertilizes the eggs with sperm. The eggs hatch into spherical larvae, which then find a place to mature to adulthood. Some rag-worms are hermaphrodites and have the extremely rare ability to fertilize their own eggs.
Two rag-worms mating