Larval Development and Population Biology of Dendrocephalus Geayi Daday, 1908 (Anostraca) in Temporary Ponds From Venezuela

Abstract

D. geayi Daday, 1908 is the most common fairy shrimp in Venezuela. It has one generation per year, appearing in temporary ponds during the months May through August. The life cycle lasts for nearly 1.5 months. Eggs have a polyhedral shape, an external cortex, an alveolar layer and a cuticle that surrounds the embryo. Dry resting eggs activate when immersed in water for 24-48 hours. Larval development starts with nauplii that through successive molts gradually differentiate into the adult in approximately 20 days. Life cycle in field populations lasts 30 to 45 days. Maximum egg production was 900 eggs in a single clutch, average 797.5. Growth of a population can be represented in a regression line formula Y = 10.41 + 0.56X. Extinction of year populations is due mainly to predation by fish and shrimps that reach the ponds after flooding of the area.