Little crawlers grow up

Six-week old Cornu aspersum (a.k.a Cantareus aspersus or Helix aspersa), the common garden snail. Born transparent, they began developping shell pigmentation after a couple of weeks, starting with the bands. The final pattern of their shells however won’t be certain until they have fully grown: until then the bands continue evolving as the shell grows and may become thicker or thinner, darker or lighter, and adjacent bands may merge into a single, broader one while others may simply fade and disappear. As such, even if apparently all juveniles developped five bands at first, adults may have less.

Their bodies are still light coloured: body pigmentation will take a few months to become apparent, starting with their head and dorsal stripe.

Mother & baby

Adult Cornu aspersum, carrying one of its newborns

Close-up

More pictures of the hatchlings.

Life and romance of a one-eyed Roman snail

Or: Reproduction and Birth in Helix pomatia.

Blinded by love? Alezan the burgundy snail (Helix pomatia, a.k.a Roman snail) has only one eye. Whether this is the result of trauma or birth defect, it’s unclear, but one thing is certain: it hasn’t prevented Alezan from living a healthy, functional life – or successfully reproducing, for the matter.

Alezan and Margot, mating. Both adults (and fellow Helix pomatia Blanche, not shown)
were purchased from a snail farm in Austria

Mating in Helix pomatia occurs in a frontal, standing position: the two individuals face each other, their pedal soles in contact. As most land snails, Helix pomatia is an incomplete hermaphroditic species, with each individual having both male and female organs, but unable to self-fertilise.

Laying eggs

After mating, both adults will lay eggs, in a hole several centimetres deep in the ground, where earth is moist and soft. The eggs are fairly large (about 1cm in diametre). Egg laying is a strenuous activity, which may take up to a full day for a burgundy snail.

Alezan’s babies, leaving the nest: it may take the newborns a few days to leave the underground after hatching

Eggs were laid on September 14, and hatched after two weeks. In the wild hatchlings born so late in the year may not survive their first winter.

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Further reading:

• Helix pomatia: Mating and Reproduction (by Robert Nordsieck)
• Reproductive performance of Helix pomatia (Gastropoda: Pulmonata: Helicidae) and survival of its hatchlings under farm conditions (American Malacological Bulletin)

Hatchlings

Barely 3mm in size, these Cornu aspersum explore the world for the first time. Eggs hatched after 12 days of incubation, and the fully formed and self-sufficient baby snails emerged from the ground, crawling their way to food and shelter.