• N Murugan

      Articles written in Proceedings – Animal Sciences

    • Laboratory studies on the life span, growth, fecundity and embryonic development ofDaphnia cephalata King (Crustacea: Daphniidae)

      N Murugan R K Moorthy

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      Studies onDaphnia cephalata, relating to its longevity, instar duration, growth and fecundity have been made. Fifteen of the 22 individuals reared became primiparous at the fourth instar, the remaining at fifth. During growth, the total length, carapace length and carapace height increased by 2·95, 2·20 and 1·79 mm respectively and the growth curves for the 3 morphometric dimensions are of the same shape. About 200 eggs were produced during the life span of 52 days when the animals were reared at 27±2°C. The early embryogeny resembles other tropical daphnids but for differences in the developmental period in the brood chamber.

    • Population dynamics ofMoina micrura Kurz (Cladocera: Moinidae) inhabiting a eutrophic pond of Madurai (south India)

      N Murugan

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      Population density, composition, age structure and fecundity ofMoina micrura have been studied in a eutrophic pond. The average clutch size of this species ranged from 1–4·4 eggs. The relationship between mean brood size and body length has been established. The volume of parthenogenetic eggs of this cladoceran ranges between 0·2 and 0·9 million μ3 and the adaptive significance of this has been discussed. The mean instantaneous birth rate which preceded maximum density of population resulted in a value of more than one.

    • Dynamics of a population ofCeriodaphnia cornuta Sars (Crustacea: Cladocera) from a seasonal pond in Madurai

      N Murugan

      More Details Abstract Fulltext PDF

      Investigation of the dynamics of a population ofCeriodaphnia cornuta indicated that the internal and external phenomena of clutch size and food supply were significant factors influencing population density and other population parameters. The relationships of clutch size with transparency and temperature were attempted. A single period of bisexual reproduction was noticed over a period of 12 months. The mean annual clutch size ranged from one to two eggs. Animals with 3 eggs were far fewer in percentage in the natural habitat. A low positive correlation of r=0·27 was recorded between mean brood size and body length, indicating that small body size naturally restricts the egg laying capacity of the females. The absence of size groups III and IV in the field samples was explained. The population parameters such as finite birth rate (B), instantaneous birth rate (b) population change (r) and death rate (d) were estimated from field data for this cladoceran.

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