Agriculture Reference
In-Depth Information
complex due to rearward displacement of the gizzard and clitellum to allow the devel-
opment of a strong anterior musculature (Bouché, 1972). This evolutionary advance
improved the ability of the Lumbricidae to dig deep burrows and to drag leaves into them.
Nonetheless, during mating, spermatozoa are transported from the male pore to the
spermathecae of the partner via an external tegumental fold (Figure III.41).
Mating occurs when male apparatus is fully developed. Since the female organs
generally mature some days to weeks later, spermatozoa are stored in spermathecae.
Eggs are laid in a cocoon excreted by the clitellum, an annular or saddle-shaped conspic-
uous protuberance situated in the anterior part of the body. Cocoons vary in size from 1 to
25 mm, depending on the size of adults. In each cocoon, up to 10-12, but most frequently
one or two embryos develop (Lavelle, 1981). Cocoons possess a thick external chitinous
envelope with a gelatinous filling which provides food for the developing embryo(s)
(Figure III.42). They have a remarkable ability to resist both drought and infection.
