Ecology and behavior Brine shrimp

1 ecology , behavior

1.1 reproduction
1.2 parthenogenesis
1.3 diet

ecology , behavior

brine shrimp can tolerate levels of salinity 25‰ 250‰ (25–250 g/l), optimal range of 60‰–100‰, , occupy ecological niche can protect them predators. physiologically, optimal levels of salinity 30–35‰, due predators @ these salt levels, brine shrimp seldom occur in natural habitats @ salinities of less 60–80‰. locomotion achieved rhythmic beating of appendages acting in pairs. respiration occurs on surface of legs through fibrous, feather-like plates (lamellar epipodites)

reproduction

males differ females having second antennae markedly enlarged, , modified clasping organs used in mating. adult female brine shrimp ovulate approximately every 140 hours. in favourable conditions, female brine shrimp can produce eggs hatch. while in extreme conditions, such low oxygen level or salinity above 150‰, female brine shrimp produce eggs chorion coating has brown colour. these eggs, known cysts, metabolically inactive , can remain in total stasis 2 years while in dry oxygen-free conditions, @ temperatures below freezing. characteristic called cryptobiosis, meaning hidden life . while in cryptobiosis, brine shrimp eggs can survive temperatures of liquid air (−190 °c or −310 °f) , small percentage can survive above boiling temperature (105 °c or 221 °f) 2 hours. once placed in briny (salt) water, eggs hatch within few hours. nauplius larvae less 0.4 mm in length when first hatch. brine shrimp have biological life cycle of 1 year.

parthenogenesis

the effects of central fusion , terminal fusion on heterozygosity

parthenogenesis natural form of reproduction in growth , development of embryos occur without fertilisation. thelytoky particular form of parthenogenesis in development of female individual occurs unfertilised egg. automixis form of thelytoky, there different kinds of automixis. kind of automixis relevant here 1 in 2 haploid products same meiosis combine form diploid zygote.

diploid artemia parthenogenetica reproduce automictic parthenogenesis central fusion (see diagram) , low nonzero recombination. central fusion of 2 of haploid products of meiosis (see diagram) tends maintain heterozygosity in transmission of genome mother offspring, , minimise inbreeding depression. low crossover recombination during meiosis restrains transition heterozygosity homozygosity on successive generations.

diet

in first stage of development, artemia not feed consume own energy reserves stored in cyst. wild brine shrimp eat microscopic planktonic algae. cultured brine shrimp can fed particulate foods including yeast, wheat flour, soybean powder or egg yolk.