Life cycle, feeding and adaptive strategy implications on the co-occurrence of Argyrodiaptomus furcatus and Notodiaptomus iheringi in Lobo-Broa Reservoir (SP, Brazil)

Abstract

The population dynamics, life cycle and feeding of Argyrodiaptomus furcatus and Notodiaptomus iheringi, were studied in Broa reservoir from August 1988 to August 1989, period when a replacement of A. furcatus by N. iheringi was observed. Some abiotic factors such as temperature, dissolved oxygen, pH and conductivity were measured to characterize the limnological conditions of the reservoir. Also, phytoplankton composition was analyzed and related to the feeding of the two species. Experimental data on developmental time and reproduction of A. furcatus and N. iheringi under different temperatures showed that lower temperatures were responsible for density decreasing of both populations in the reservoir during the dry season. Chlorophyta and Chrysophyta smaller than 20 microns were the most abundant phytoplankton groups in the reservoir as well as in the gut content of A. furcatus and N. iheringi, representing an important food source for both species. The temporary disappearance of Argyrodiaptomus furcatus, observed between 1988 and 1989 and its replacement by Notodiaptomus iheringi was related to mining activities upstream, modifying the water turbidity, pH and conductivity. However, the reappearance and maintenance of A. furcatus for another ten years and a recent replacement re-incidence indicates that these two calanoids do not coexist in this environment. Adaptive strategies of both species, related to changes in environmental conditions, are discussed. Probably, Argyrodiaptomus furcatus is an indicator of less eutrophic environments, while Notodiaptomus iheringi of more eutrophic systems.

Zooplankton biomass of reservoirs in different trophic conditions in the State of São Paulo, Brazil

“…Declining calanoid densities in Guarapiranga were probably due to lower water temperatures recorded during the cold season. Notodiaptomus iheringi was important due to its ability to replace other calanoid species in eutrophic waters (Coelho-Botelho et al, 1999;Rietzler et al, 2002).…”

Copepods (Crustacea, Maxillopoda) from shallow reservoirs

“…At the moment it is not possible to suggest what conditions they need to survival, or set of them, but it is evident that Calanoida is more sensitive than Cyclopoida in the reservoirs have caused changes in the composition of calanoids in the whole State of São Paulo. In some reservoirs, as in Broa, the replacement of species formerly dominant has been observed, such as Argyrodiaptomus furcatus by N. iheringi, which is more tolerant (Rietzler et al 2002, Tundisi andMatsumura-Tundisi, 2003). The highest frequency and densities of N. iheringi in the studied reservoirs can reinforce its higher capacity to tolerate the eutrophic state environments than the other Calanoida species.…”

Copépodes (Crustacea, Calanoida, Cyclopoida) planctônicos em reservatórios profundos e dendríticos: efeitos do tempo de residência e da idade de formação

“…Embora o tempo de residência de Salto Caxias não seja muito elevado, ele pode ser o necessário o suficiente para que organismos adultos completem o ciclo de vida, estimado para espécies neotropicais de copépodes em torno de 20 dias (Rietzler et al 2002). Efeitos dessas características sobre o zooplâncton são apontados por outros autores (Rocha et al 1999;Bonecker et al 2001;Bini et al 2008).…”

“…Muitas espécies podem ser associadas com variáveis físicas e químicas do ambiente, como por exemplo, a condutividade e composição iônica (Matsumura-Tundisi & Tundisi, 2003), a temperatura (Rietzler et al, 2002) e o grau trófico (Silva, 2011).…”