Lymnaea Snail Eggs

Snail Chain ©Creative Commons BY-NC-ND, Eric Heupel 2008

One small section of a BUNCH of Lymnia sp. snail eggs pulled from our fresh water aquarium. They like to lay their egg clutches on the underside of larger broad leaved aquatic plants.
These snails are reproductive powerhouses! Not only are they simultaneous hermaphrodites which practice sperm sequestration and/or self fertilization, but they reach reproductive maturity and begin egg laying only a month after hatching or “eclosion.” Combine that with the 20-40 eggs per clutch they lay, and one can see how they can quickly grow the population.

Lymnaea sp. snail eggs ©Creative Commons BY-NC-ND, Eric Heupel 2008

This shot was lit by the microscopes flourescent base light from below and a pair of remote flashes from above, giving pretty good definition to the individual eggs and inside the invisible gelatinous mass. The following shot was with the base CFL illuminator only.

Bottom lit Lymnaea snail eggs ©Creative Commons BY-NC-ND, Eric Heupel 2008

Did I mention they were prolific breeders? Every six months to a year we break down one of our two freshwater aquariums and rebuid it. The last time we made sure there are no eggs on the plants. After a full month of no snails we introduced one small adult snail. Two months later there were nover 50 snails in the tank. This time no adult snails. We have a single egg mass with 13 eggs in it. We’ll see how far we let those go.

As long as I’m not subjected to further displays of their extreme hermaphroditic proscuousity!

PZ Myers has a great post realted to these snails that shows the early development of the Lymnaea zygote, especially focussed on the 3rd division from four cells to eight, which begins the pattern of molluscan spiral cleavage. The details of that division have profound effects on the organism, including whether they are sinestral or dextral.

Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
Order: Pulmonata
Family: Lymnaeidae
Genus: Lymnaeas