Background

Chydoridae is the most diverse family of cladocerans but information about their biology or life cycles is still limited, perhaps because of the hard task that their taxonomy involves or that culture in optimal conditions are not described for several species.

Goals

This study examined the effects of culture conditions (algal concentration, algal species, and temperature) on the demography of Alona guttata (Sars, 1862) to obtained their maximal growth rates.

Methods

Life table analysis with the chydorid A. guttata were performed as follows: five females per cohort (six replicas) were fed on either Chlorella vulgaris (Beijerinck, 1890) or Nannochloropsis oculata (Hibberd, 1981) at 0.5×106 or 2×106 cells/mL, reared at 20ºC or 25ºC and photoperiod 16:8 h (light: dark). Media was supplemented with an artificial substrate. Then, daily fertility and survival were assessed to estimate the demographic parameters: average lifespan (ALS), life expectancy at birth (LEB), generation time (GT), gross reproductive rate (GRR), longevity, net reproductive rate (NRR), and the intrinsic rate of population increase (r).

Results

Significant effects were observed due to the three factors tested and their interactions. Increasing algal concentrations of either C. vulgaris or N. oculata promoted higher fertility and longer survival. Lower temperature extended the ALS and LEB when organisms were fed on the highest algal concentration. The highest r values were observed when Alona was fed on N. oculata at 2×106 cells/mL.

Conclusions

The best culture conditions, in terms of the population growth rates of A. guttata, were provided by N. oculata at 2×106 cells/mL at 25°C with the supplementation of artificial substrate.