How HERMAPHRODITE ANIMALS reproduce

We always hear of male animals with male gametes and female with female gametes, but did you know that there are individuals with both types of gametes? They are the so-called hermaphroditic animals and can follow different reproductive strategies. In this lesson from a PROFESSOR we tell you how hermaphroditic animals reproduce. Join us to discover more!

The hermaphroditic animals or monoecious (term more commonly used in plants) are those that are capable of producing gametes male and female, since they have both types of reproductive apparatus (female and male).

However, that they are hermaphrodites does not mean that they are hermaphroditic throughout their lives. Thus, we call permanent or simultaneous hermaphroditism to that which occurs throughout the life of the animal, while in the sequential hermaphroditism, the animal can change its reproductive organ throughout its life cycle. This is very common in fish, such as clownfish.

The hermaphroditism is usually more common in solitary animals

, since they have little chance of meeting a couple of the same species, so when this happens they need possess both reproductive organs to increase their chances (as we will see, these individuals do not usually fertilize themselves themselves).

To know how hermaphroditic animals reproduce, you have to take into account that they exist two forms of fertilization in hermaphroditic animals:

• Selfing: in this form of fertilization, the same individual can join his male and female gametes to give new individuals.
• Cross fertilization: in this form of fertilization, two parents are required to exchange their male and female gametes simultaneously. This type of fertilization occurs, for example, in snails.

Contrary to what one might think, in hermaphroditic animals the cross-fertilization is much more frequent than in self-fertilization. An advantage of sexual reproduction is genetic variability, which allows offspring to be more adapted to the environment. However, with self-fertilization this variability is very low or null, while with cross-breeding this is maintained.

Regarding genetic variability, self-fertilization is intermediate between asexual reproduction and sexual reproduction, since that in the same process of gamete formation there is a crossover between chromosomes, giving rise to new combinations of genes. In addition, there are processes that increase genetic variability such as mutations.

Cross-fertilization usually include complex courtships, as in snails, and they are usually external fertilizations, in which the gametes are released into the environment and are fertilized. In addition, some have sac-like structures that house sperm. These sacks are wrapped in a capsule that can produce nutrients.

Hermaphroditism is not a very common characteristic, since the vast majority of animal species have male or female gametes and their sex is determined by their genetic endowment. In addition to the vast majority of plant organisms, among hermaphroditic animals we can highlight the following.

Earthworms

Earthworms possess both reproductive organs and when they mate by cross-fertilization, they lay a bag of eggs in a well-protected location.

Prawns

Shrimp are not hermaphrodites throughout their lives, but are usually male at an early age and become female at a more mature age.

Sea stars

Starfish are usually male at juvenile ages and change to female at mature ages, but they can even have asexual reproduction, producing identical offspring. This reproduction happens when an arm breaks and takes a part of the center of the star. Later, this arm will regenerate and regenerate the rest of the body, producing another identical individual.

I had

Tapeworms do resort to self-fertilization, since being internal parasites of animals it is very difficult for them to meet another individual of their species. Still, when given the opportunity, they prefer cross-breeding.

Fishes

Up to 2% of fish species are hermaphrodites, many of them change their sex throughout their lives. The pallid serrano stands out, which is a fish with both sexes developed and that changes partners up to 20 times a day. There are colonies in which the dominant male lives with a harem of females, and when they die, the larger female takes on the role of male and takes the lead of the colony.

Frogs

There are hermaphrodite species, such as the African tree frog, which during juvenile age is male and mature into female in adulthood.

Other examples

Other hermaphroditic animals are snails (well known), slugs, limpets, sea sponges, worms planes, sea dancers, corals, amoebas, salmon, anemones or freshwater hydras, among others animals.