Effect of food density on male appearance and ephippia production in a tropical cladoceran, Moina micrura Kurz, 1874

Abstract

A study was conducted to investigate the effects of different food concentrations consisting of Nannochloropsis oculata (4 × 102, 4 × 104, 4 × 106 cells ml− 1 and control) on male and ephippia production in a tropical cladoceran, Moina micrura. The highest number of males (186.7 ± 13.4 males l− 1) was produced in cultures fed with 4 × 102 cells ml− 1 of N. oculata (FC 3) when the population density reached > 1600 individuals l− 1. Similarly, the highest total mean number of ephippia (160.0 ± 0.0 ephippia l− 1) was achieved in M. micrura culture supplied with 4 × 102 cells ml− 1 of N. oculata (FC 3). The second highest ephippia density was found in M. micrura cultures fed with 4 × 104 cells ml− 1 of N. oculata (FC 2) which produced a mean total of 93.3 ± 13.4 ephippia l− 1 in a population density of > 3000 individuals l− 1. However, with a population density of > 4000 individuals l− 1, but fed with the highest food concentration of 4 × 106 cells ml− 1 N. oculata (FC 1), no ephippia was produced although males were present in the culture. This study illustrates that ephippia were produced in high density cultures with the presence of males and insufficient food supply. Crowding could trigger the production of males, but was not an adequate stress factor for inducing the formation of ephippia. Similarly, food limitation alone did not induce the production of males and ephippia without crowding.

Zooplankton competition promotes trade-offs affecting diapause in rotifers

“…mL −1 ] and in the absence of this cladoceran. This Moina density is approximately twofold the maximum density found in field temperate populations (Ramos-Jiliberto and Aránguiz-Acuña 2007), and about half the maximum levels recently reported in laboratory cultures (Azuraidi et al 2013). Cultures were maintained in 1,000 mL of COMBO medium, with five replicates for each condition, a photoperiod of 12-h:12-h (L:D) and 20 °C temperature.…”

Enrichment of freshwater zooplankton Moina micrura with probiotics isolated from microalgae

“…The number of M. micrura were recorded daily throughout the experiment. The population growth rate was calculated according to the following (Khatoon et al, 2013;Azuraidi et al, 2013):…”

Growth of tropical cladocerans Ceriodaphnia cornuta G.O. Sars, 1885 and Moina micrura Kurz, 1875 fed with different diets

“…When the population stabilized or began to decline the experiments were terminated. Every third day, population density for both species were determined by removing 25 ml of wellmixed culture and counted under a dissecting microscope (Azuraidi et al, 2013). Population growth rate was calculated by the following formula:…”

“…Ceriodaphnia cornuta and Moina micrura are freshwater zooplankton, commonly found in tropical lakes and ponds. Moina micrura is an important live food in aquaculture since it is rich in nutritional contents and capable of improving larval growth and development of many cultured species (Azuraidi et al, 2013). In general, cladocerans are ideal live foods as they have digestive enzymes, high nutritional quality, and suitable body sizes (0.2-6 mm) for many species of fish and invertebrate larvae (Dodson and Frey, 1991;Kumar et al, 2005;Nandini and Sarma, 2003;Srivastava et al, 2006).…”