The life-cycle of Ceriodaphnia silvestrii Daday, 1902, a Neotropical endemic species (Crustacea, Cladocera, Daphnidae)

FONSECA¹, A. L & ROCHA², O.

¹ Universidade Federal de Itajubá – UNIFEI, Av. BPS, 1303, Bairro Pinheirinho, CEP: 37 500 903/Itajubá/MG; e-mail: afonseca@unifei.edu.br

² Depto. de Ecologia e Biologia Evolutiva, Universidade Federal de São Carlos, Via Washington Luiz, Km 235, CP 676, CEP 13560-905, São Carlos, SP.; e-mail: doro@power.ufscar.br

ABSTRACT: Considering the scarcity of detailed information on the life cycle of Neotropical cladocerans, a study was conducted to get the necessary information to maintain cultures of Ceriodaphnia silvestrii in laboratory, aiming its use as a standard test-organism in ecotoxicological tests. Additionally, the life history information may help to understand the functional role of the species in natural communities, since it has a wide geographical distribution and sometimes occurs in high densities. The cladoceran culture was kept under constant conditions (Monoraphidium dybowskii at 105 cells.mL^-1, photoperiod 12h light : 12h dark and water temperature of 25 ± 20ºC). The parameters observed were: individual growth, population growth, biomass, fecundity and longevity. The following results were obtained: final body length of 1.0mm; intrinsic natural rate of increase (r) of 0.34 d^-1; fecundity of 9.46 ± 4.17 eggs per female; longevity of 29.8 ± 5.89 days; size at maturity was 0.57 ± 0.04mm, and dry weights for neonates and primipara were 3.8 ± 1.69 and 9.7 ± 3.3 mg, respectively. This species can be readily cultured in the laboratory, and had excellent performance in the conditions tested. It can therefore be used for ecotoxicological tests.

Key-words: Zooplankton, life cycle, Cladocera culture, Ceriodaphnia silvestrii.