An Overview of Hermaphroditic Marine Species

According to a study and research article entitled Macroevolutionary Patterns in Marine Hermaphroditism is defined as, “...in which individuals produce both male and female gametes in their lifetime, occurs in almost all higher plants (95%) and around a third of animals (excluding insects [Avise 2011]).” (Jarvis et al). Many marine species including can produce both male and female gametes or cell (to produce a zygote, the production of an offspring). Oftentimes, even marine plants can produce both sexes cells to produce a zygote. Similar to intersex humanoid individuals, marine species such as Antillean Marine Hermit Crabs and Clownfish are both examples of hermaphrodites while seashorses are considered reversed sex roles in which the male produces eggs in which the female produces sperm cells to fertilize the male’s egg.

Moreover, many species of marine Hermit Crabs like the Clibanarius antillensis are titled as marine hermaphrodites; this species will be focused on in this section. You may know that all hermit crab species, whether land or marine, have a set of gonopores, which are tiny pores in the farthest legs of their body, and have a purpose of reproduction. When stimulated, gonopores receive the sperm of the opposite sex, and intake what is called a spermatophore, a packet which stores the sperm specimen until the crab’s eggs can be fertilized. In order to understand the hermaphroditic Clibanarius antillensis (Antillean), you must understand that when that species of hermit crab molts (the process of burrowing underground and shedding their exoskeleton to harden their new exoskeleton, then returning to the upper ground), they will appear to have changed their sex as their gonopores may appear or disappear. This is because marine and land hermit crabs contain both sex cells as the molting process takes place. Although studies have not been done to know how or why some hermit crab species can lose or gain gonopore’s, it is understood that the sex of an Antillean hermit crab can be determined by checking the underside of their stomach. If there is a set of dots on the third leg joint above the abdomen, the hermit crab is a female; if not, the crab is a male.

In contrast, for seahorses, the Hippocampus kuda, they can live for three to five years, and can always be found in saltwater. In a scientific study done by Qin et. al, “Females transfer large, yolk-rich eggs into the specialized brooding structure (brood pouch), which the males immediately fertilize, and the male incubates developing embryos in the brood pouch where embryos are aerated, osmoregulated, protected and likely provisioned during their development.” (Qin et. al). Different to an Antillean Hermit Crab, male seahorses hold the developing embryo made from the female's eggs to the male’s brood pouch, where they take on several stages in development, and soon are released into the wild. The average number of offspring in a brood pouch is anywhere in between a few dozen and two thousand.

On another note, clownfish, the Amphiprion ocellaris, live in anemones their entire life and can live up to ten years. Clownfish are another perfect example of marine hermaphrodites, in which they are born when sex and then will change to the other sex, as they have both female and male reproductive organs, similar to the species of marine hermit crabs discussed before. Clownfish, in short, are protandrous, and live in sea anemones in groups of two and a multitude of small fish. Two of the largest fish are the only fish that are sexually mature, being a male and female breeding pair (both sexes). The smaller fish are all male. In an informative article about hermaphroditic marine vertebrates, the author states, “If the large breeding female is removed, her male mate changes sex to female and the next largest fish in the group rapidly increases in size…" (Understanding Evolution). After, the largest fish in the group grows at a substantial rate and takes over the role as the mature male.

As proven above, marine species such as Antillean marine hermit crabs and clownfish are both examples of hermaphrodites while seashorses are considered reversed sex roles in which the male produces eggs in which the female produces sperm cells to fertilize the male’s egg.