Life cycle of Macrothrix flabelligera Smirnov, 1992 (Cladocera, Macrothricidae), recently reported in the Neotropical region

Abstract

Information on the life cycle of individual species is vital to an understanding of their ecology, particularly their distribution. In this investigation, aspects of the Macrothrix flabelligera (Cladocera, Macrothricidae) life cycle were studied in laboratory cultures under controlled conditions. Neonates from parthenogenetic females previously acclimatized were isolated and grown at constant temperature, in a 12-h/12-h light/dark cycle. Organisms were fed with a suspension of Scenedesmus bijugus at a concentration of 10⁵ cells ml⁻¹. Daily measurements of body length and age were made, to obtain the growth rate, size and age of primipara. M. flabelligera had high fecundity rates, producing broods of 13.6 eggs female⁻¹. At 23.0 °C, the duration of embryonic and post-embryonic development was 35.9 h and 4.9 days, respectively. The mean longevity was 12.7 days. A length–weight relationship was established and used to convert measured length into weight, in order to plot weight growth curves, as subsidiary information for future secondary production calculations.