Annelida: Leech Reproduction

Like the oligochaetes, leeches are hermaphroditic and cross-fertilizing, although fertilization is internal. In some species the sperm are enclosed in sacs, called spermatophores, that are attached to the outside of the partner; the sperm pass through the body wall to the ovaries, where the eggs are fertilized. In other species the sperm are not enclosed and are transferred directly into the body of the partner by copulation. A courtship display is seen among some leeches at the time of mating. The fertilized eggs are deposited in a cocoon, secreted by the clitellum; the cocoon is buried in mud or affixed to submerged objects. The young emerge as small copies of the adults.

Sections in this article:

• Introduction
• Leech Reproduction
• Leech Predation and Digestion
• Leech Anatomy
• Class Hirudinea
• Oligochaete Reproduction
• Oligochaete Circulation and Respiration
• Oligochaete Digestion
• Oligochaete Anatomy
• Class Oligochaeta
• Archiannelida and Myzostomaria
• Polychaete Reproduction
• Polychaete Anatomy
• Sedentary Polychaetes
• Errant Polychaetes
• Class Polychaeta
• Reproduction
• The Nervous System
• Respiration
• Circulation
• Digestion
• The Body Wall
• Segmented Bodies
• Bibliography

The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2024, Columbia University Press. All rights reserved.

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