The life cycle of Mononchoides fortidens (nematoda: Diplogasteroidea) with emphasis on gonad development

Abstract

Mononchoides fortidens reproduced by amphimixis. Smooth, elongate eggs measuring 60-80 x 35-45 |xm were laid in single-cell stage. Embryonic and post-embryonic development lasted for 16-20 h and 3-6 days respectively. Sexes were first distinguished during second moulting by the anterior elongation of primordium in males and anterior as well as posterior elongation in females. The aggregation of cells dorsal to the rectum in males represented the site of spicule formation. In females specialized ventral chord nuclei on the mid-ventral side of genital primordium formed the vagina. A flexure developed first in the third stage male, and later in fourth stage females. The life cycle from egg to adult was completed in 4-7 days. Keywords: nematode biology, development, reproduction, embryology.