This box jellyfish is an animal that can go undergo gametic meiosis and asexual reproduction, reproduction without sex. Let's start discussing the life cycle beginning with the mature organism. During the months of spring, the mature box jelly makes its way to a nearby freshwater river to search for a compatible mate. Once they find this mate, the female releases her eggs and the male releases his sperm into the water. However, once these jellyfish spawn they die and do not participate in the upbringing of their descendants. The egg and sperm haploid forms of the Chironex fleckeri life cycle are called gametes. Once one egg and one sperm meet, they fuse together and are a fertilized zygotic cell. This cell undergoes mitosis and forms a planulae. These planulae grow into a polyp that is approximately 1-2 millimeters in length. This polyp stage of the jellyfish usually has two tentacles attached to it. These are used to attach the polyp to any hard surface, most of the time on the underside of a crevice or somewhere else where they are not exposed to predators. While these polyps are growing, they consume plankton as their primary means of nutrition. So far we have only seen the sexual reproductive sequence of this species, but throughout the polyp stage is when this organism can undergo asexual budding.


Budding is when a new organism grows from a parent organism. This is shown in the picture of a Chironex relative below. The new organism is growing via mitosis, and since this new organism is growing directly from the parent organism, the new individual is a clone of its parent. These parents and new polyps grow and metamorphose into small, immature medusa. These medusa then swim from the river back to the ocean where they continue to grow until they reach their sexually mature form. It takes approximately 2 months for the male and female medusa to completely sexually mature. Once this process is complete, the organism has 9-10 months of free-swimming life before it swims to a freshwater river, releases its gametes, and gives rise to another life form. Since the box jelly released its sperm or eggs, it dies in the river, living only for a very short amount of time. Chironex fleckeri is considered to be oviparous. Oviparous is a type of reproduction where the eggs are completely discharged from the female organism, and the growth of the new individual happens outside of the female's body, not inside of the body like in human reproduction.


Now that you know how Chironex fleckeri reproduces, check out how it interacts with other organisms by visiting the Interactions page.

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