Reproduction parthénogénétique deMoina macrocopa(Straus 1820) (Crustacea : Cladocera). Influence des conditions trophiques, de la densité de population, du groupement et de la température

Abstract

The fecundity and development of Moina macrocopa, the only cladoceran living in the waste water sedimentation ponds of Marrakech, have been studied in the laboratory at seven varying algal concentrations and at five different temperatures. Population density and grouping effects were also investigated.The conditions of food deficiency are one of the major cause of the reduced fecundity in Moina macrocopa. We showed, that an msufficientfood supply corresponding to an algae concentration lower than 3.125.10 4 cells/ml, would suppress (remove) any reproductive phenomenon. In contrast, the increase of resource level beyond this reproductive concentration threshold, allowed fecundity of Moina macrocopa to improve which appears as an increase in the brood number (frequency) rather than an increase of the brood size.The experiments also allowed us to show the harmful effect of an increase of population density on the fecundity of M. macrocopa. However, no grouping effect on reproductive processes has been observed in this species.

Distribution and biological aspects of the introduced speciesMoina macrocopa (Straus, 1820) (Crustacea, Cladocera) in the semi-arid central region of Argentina

“…Anthropic eutrophication, which is due to the input of an excess of nutrients (phosphorus and nitrogen) into any water body, can come from three sources: industrial, domestic or agricultural (Freitas & Rocha 2011). In other parts of the world, M. macrocopa is often associated with hypertrophic or eutrophic environments with high anthropogenic influence, especially those under the influence of cities; for example, sewage treatment basins or rivers with strong domestic organic pollution, such as the Mula River in India (Vanjare et al 2010), or those impacted by industrial activities, such as lakes for paper-making industry sewage treatment (Espinosa-Chávez et al 1992, Martínez & Gutiérrez 1997, Benider et al 1998. In all cases, the constant discharge of wastewater increases their organic load, usually resulting in pollution (Loh et al 2009).…”

“…Moina macrocopa is a cladoceran which has been mainly recorded in water bodies under heavy anthropogenic influence, such as sewage treatment basins, lakes for the paper-making industry sewage treatment, or rivers with strong domestic organic pollution (Espinosa-Chávez et al 1992, Martínez & Gutiérrez 1997, Benider et al 1998, Vanjare et al 2010. It is a species whose populations play an important role in food webs of epicontinental aquatic environments (Iannacone & Alvariño 2000) and is of economic importance, since it is used in aquaculture as live food for larval stages of some fish.…”