In spring, when the Roman snails have been awake from hibernation for some time, it becomes time for mating. Roman snails are hermaphrodites. They have male, as well as female organs in one collective genital apparatus. As a hermaphrodite, the Roman snails have double mating chances, because they can mate with any other Roman snail. Besides, during copulation, Roman snails do not act as either male or female, but simultaneously as both.
Attraction and Courtship
The encounter of two Roman snails ready for mating is not purely incidental. Like many other terrestrial snails, they as well have a gland located at the gland that produces an olfactory sexual attractant.
Both snails begin by raising their heads and putting their flat foot soles against each other. They touch each other with tentacles and lips. As a prelude to the actual copulation this courtship process may last as long as twenty hours.
Application of the Love Dart
During the courtship possibly a dart may be applied, one snail stinging it into the mate's foot. A Roman snail's love dart can become as long as 7 to 11 mm. To use the dart, the snail pushes out the interior of the dart sac, thus thrusting the dart into the mate's body. Then the dart remains stung in the body. But the love dart is not applied in every mating process.
Using a love dart a secretion is injected. This secretion contains hormones, that influence certain parts of the genital apparatus and that way improve the reproductive chances of the snail that applied the dart.
After the long and extensive courtship there may be several attempts on copulation. When finally both snails managed to find a suitable position, they actually perform copulation. Both penises are entwined and inserted into the mate's vagina. At the same time, a sperm packet, a so-called spermatophore, is produced in either snail's body and afterwards filled with sperm cells. Afterwards this spermatophore is going to be placed in the genital apparatus of the mating partner.
A part of the sperm cells just received, however, will be stored in a special sperm pouch. Those sperm cells may then well manage to fertilise egg cells, though they will have to compete with sperm cells of other mating partners also stored in the same pouch.
To find a suitable place to deposit their eggs, about 4 to 6 weeks after mating, Romans snails sometimes migrate for noticeable distances. To make a hiding place for its eggs, the snail needs at least 3 to 5 cm of loose ground to dig a hole in.
Only when it is finished digging a suitable hole for its eggs, the Roman snail will take a break of several hours, during which it will stay at the hole and begin to fertilise the egg cells and to produce eggs.
The Roman snail deposits an egg of about 6 mm diameter (0.1 to 0.2 g weight) each 15 to 30 minutes. As the amount of eggs laid by a Roman snail may vary with age and locality, counting 40 to 60 eggs, the process of egg deposition may last between 20 and 30 hours!
When it has finished, the snail withdraws its body from the egg hole and glides over the opening to close it with earth crumbs.
Snails, like other molluscs, generally develop past a larval stage. The fertilised egg cell by continuous cell cleavages an embryo form, that gradually develops into a larva.
It is not only sea snails, but also terrestrial snails that develop past such a larval stage. A Roman snail larva does not resemble the adult. All of the snail's embryonic and larval development takes place inside the egg. The development is concluded by a metamorphosis, during which the larva changes its shape and develops into a juvenile snail.
The young snail is hatching after 25 days from a Roman snail's egg. Only the genital organs are not yet developed. The snail's hermaphroditic gland will have to mature, so it is able to produce egg and sperm cells by the third life year of the young snail.
The first 8 to 10 days after hatching the juvenile snails stay in the earth hole that serves as their hatchery. In this time they eat the remains of their eggs. From their earth hole the juvenile snails have to free themselves on their own. They eat and dig through the earth cover until they reach the surface.
In the months until their first winter, depending on food supply, the may reach 10 mm in size. Maturity they generally will only reach after their second winter. Until then their shell will have grown to 5 whorls and 40 mm in diameter.
It will be a long way to go. In nature, only about 5% of young snails manage to survive until maturity.
Roman Snail while Reproduction
Love Dart of the Roman Snail
Spermatophore placed in Genital Apparatus
- Picture: Weichtiere.at -
Hole for Eggs
Roman Snail Baby
- Picture: Weichtiere.at -