Life table demography and population growth of Daphnia laevis (Cladocera, Anomopoda) under different densities of Chlorella vulgaris and Microcystis aeruginosa
Por:
Nandini S., Sarma S.S.S., Ramírez-García P.
Publicada:
1 ene 2000
Resumen:
The authors studied the life table demography and population growth of Daphnia laevis using the green alga Chlorella vulgaris and the cyanobacterium Microcystis aeruginosa (offered in colonial form) under two food concentrations (1 × 106 and 3 × 106 cells ml-1). The experimental design consisted of two types of food, and of two concentrations of algae, each with three replicates. The design was the same for both the life table study and the study of population growth. The variables derived were: age specific survivorship, age-specific reproduction, average lifespan, age-specific life expectancy, gross reproductive rate, net reproductive rate, generation time, reproductive effort, stable age distribution, and rate of population growth derived iteratively. While survivorship variables were not affected significantly either by the type of food or by the concentration offered, reproductive variables of D. laevis were significantly influenced by the type of alga rather by than its density. Cladocerans fed Chlorella reached maximal population abundance earlier than those fed Microcystis. Throughout the population growth study, peak population abundance values of D. laevis varied from 0.34 to 0.49 ind. ml-1. There was no significant difference in the peak population density reached with respect to food type or food concentration. The rate of population growth per day varied from 0.1 to 0.15. Our study indicates that D. laevis can successfully utilize a basically toxic strain of M. aeruginosa, with which it co-exists in a man-made reservoir in Mexico.
Filiaciones:
Nandini S.:
Division of Research, National Autonomous University of Mexico (UNAM), Campus Iztacala, Av. de Los Barrios s/n, C.P. 54090, Tlalnepantla, Los Reyes, Edo. de Mexico, Mexico
Sarma S.S.S.:
Biology Division, National Autonomous University of Mexico (UNAM), Campus Iztacala, Av. de Los Barrios s/n, C.P. 54090, Tlalnepantla, Los Reyes, Edo. de Mexico, Mexico
Ramírez-García P.:
Division of Research, National Autonomous University of Mexico (UNAM), Campus Iztacala, Av. de Los Barrios s/n, C.P. 54090, Tlalnepantla, Los Reyes, Edo. de Mexico, Mexico
|