13 December 2007

Sleeping snail

In a post I wrote back in August, when it was hot and humid, I speculated that terrestrial invertebrates, like some plants, may need to go thru a cold-induced winter dormancy (vernalization) before they can start reproducing in the spring.

Now that the weather is cold, there are plenty of opportunities to follow up on that idea. At every opportunity, I am going out to look for live snails and to record what they are doing.

DecemberSnail1

I found this one yesterday in the woods. It was in tight-fitting hole in the soil under a layer of leaves. As you can see in the next photo, its aperture was closed by a membrane formed from the snail's slime.

DecemberSnail2

It is a juvenile of either Mesodon thyroidus or Neohelix albolabris, two species of this area that are difficult to distinguish from each other before they become adults. Although they do have differences in their microsculptures visible at high magnification under a microscope, I didn't want to take this snail with me home just to identify it. That would have defied the purpose of the study: I want to know how long this particular individual will stay dormant in that location.

DecemberSnail3

So, I placed the snail back in its hole, covered it up and then marked the spot. I will return there throughout the rest of the winter and check up on it. If it stays where I left it until about the middle of March, then I will take it to identify it.

1 comment:

pascal said...

I'd be interested to see what happens. I took a few succinids out of hibernation, and got snail eggs afterwards.