Snail Collection (and a bit about sex) - by Hannah Swim

It’s Friday morning which means I’m reaching for my swimsuit rather than my usual jean shorts and tank top. I groggily make my way to the kitchen for a quick bite to eat, grab my supplies for lab, and head straight for the boat ramp.  I see that the water is calm with a smooth glassy surface, perfect conditions for a morning kayak along the mangroves to collect snails.

The snails wait patiently to be returned to the
mangrove roots where they live.

I awkwardly heave the large yellow kayak off its rack behind the dive locker, and lug it down to the boat ramp.  It will not be one of my more graceful moments today, but my arms have gotten stronger after eight weeks of moving it in and out of the water. I haven’t been outside for more than 5 minutes and I’m starting to sweat in the heavy Caribbean humidity.  I think I’ll go for a quick swim after I get back. 

With my lifejacket on and falcon tubes between my legs I push off and begin to paddle my way around the dock.  Last week the water was rough so I am thankful that today it is calm which allows me to glide silently.   First stop is the area of mangroves just past the docks where I will drop off all the snails who have called these twenty some-odd falcon tubes, home for the past week.  Most are thrilled get ahold of some natural footing, others are a bit shyer after being pried off the lids and take a bit of time to come out of their shells again. I’m happy to wait for them to attach themselves to the branches, it is a beautiful morning.  Once my tubes are all empty I paddle north away from the docks. 

I start to collect snails from shady areas, under mangrove leaves and on low hanging branches.  I have found that setting them on top of the falcon tubes is the best way to let them come out of their shells.

How can you tell the sex? Well, the normal way, males
have a penis.  Just tip the shell up a little and have a look.

I am only interested in females, so the males are returned back to the mangroves where they will hopefully find a pretty lady to fertilize which we could collect next week. The whole collection process takes a little under and hour, and I am more than ready to take a quick dip before heading back to lab.  All my tubes have a new resident female snail with some sea water.  Most have already taken refuge on the bottom of the lids, and tend to remain there until they crawl into the water and spawn. 

The goal of this work is to find out when females release their larvae, but nailing down an exact time frame has proven more complicated than anticipated. With time we hope to be able to get a better grasp on their reproductive cycle and then we can use the newly hatched larvae to test their tolerance to heat stress.

Congratulations Matt Starr!

Matt Starr (center) with co-advisors Dr. Joe Neigel and Dr. Rachel Collin

Thursday October 30th, 2014.  Matt Starr successfully defended his mater's thesis:  Intraspecific variation and tests for positive selection on genes encoding heat shock proteins in the marine slipper snail, Crepidula fornicata

Collecting slipper limpets in Coquimbo, Chile

Collecting Snails in Chile

In June 2014 Rachel and I flew down to the Universidad Católica del Norte in Coquimbo, Chile. We met up with Marcel Velasquez, a Collin lab veteran currently at the university. As usual, we were there in search of some calyptraeids.

We had three targets: Crepipatella dilatata, Crepidula coquimbensis, and Crucibulum quiriquinae


Crepipatella dilatata and Crepidula coquimbensis were "easy" to get because they are found just off the dock and able to be collected with only snorkel gear.  But the water was COLD! So before we went swimming we needed wetsuits.








Crepidula coquimbensis lives inside hermit crabs. In order to find them, you dive down at least 10 ft and swim above the sand until you see a hermit crab running away from you. When the hermit crab pulls itself into the shell you can sometimes find a few white shells, Crepidula coquimbensis! Only the biggest females have eggs.











We also were after Crucibulum quiriquinae. These snails are easily found on the shells of Turritella cingulata but at greater depth so we hired a scuba diver to collect for us. T. cingulata were very abundant and our diver collected bags and bags of individuals. Up on the boat, Rachel and I picked through each of them in order to find the C. quiriquinae.



                                                                                     C. quiriquinae (highlighted) sitting on top
                                                                                      of a T. cingulata shell

Back in the lab we checked each of the big females for eggs!

                                                                                   

Snails Build Homes

            Do many animals build homes?  Mollusks do. And snails are a type of mollusk that make homes for themselves and for other animals, too. They make hard, mineralized shells out of calcium carbonate (CaCO₃).

At one of our field sites there is almost a carpet of shells

How much calcium carbonate do they produce? One team of biologists (Gutierrez et al., 2003) studies this idea that mollusks shells create habitats for other animals. They calculated how much they produce and found that marine mollusks may produce 50-1000 grams CaCO₃/meter/year.  Let's put that in context.  If you compare the calcium carbonate production of mollusks to the wood production of trees, they that “…persistent structure is produced by mollusks at rates comparable to trees”!

It’s easy to see the construction of habitats in action. Snail shells can be found on most beaches. Sometimes they contain the living snail. You might see their bodies in their shells, or you might see them crawling around. Other times, the snail has died and the shell is empty. If it’s intact, an empty shell can become a home to other small animals. 

Some slipper limpets living inside this moonsnail shell

Hermit crabs are a type of crab that occupies empty shells for homes, “moving in” when they need a home (see how to get hermit crabs out of the shell). Other snails can occupy vacant shells, too.  Small sponges and worms often burrow into the shell material.  Some fishes even use clam shells and oyster shells as nests for their eggs.

So, the next time you see a shell, imagine all the little animals that may have lived in it. Hooray for snails: they build homes and create communities!

by Nina Dropcho,

Collin Lab, past STRI intern