20 June, 2002
Collecting in the summer.
Considering the nature of the lab work here at Notre Dame, I am going to post entries every other day rather than post daily. I think I can discuss the lab experience very well with slightly fewer entries.
This morning everyone arrived in the lab a little earlier to prepare for a summer larvae collection trip. We drove to a forested area just north of South Bend to look for a summer sample of Cucujus beetle larvae. Collecting in the summer in Indiana is certainly a different experience than collecting on the tundra in Alaska. Our major practical concern was getting out early enough that it would not be to hot and humid for us to be out in the woods. We also got to deal with buzzing, biting insects. I am amazed at how many flies, gnats and other assorted pests a hot, sweaty person can draw in the forest. We seemed to constantly be swatting at something. Given a choice, I think I prefer collecting at Toolik.
During this morning's trip, I was also introduced to a species of beetle found commonly here in the Midwest, but not found in Alaska. The beetle, Dendroides, is similar in appearance to Cucujus and has been studied extensively by Dr. Duman's lab here at Notre Dame. They also appear to be far more numerous in this area than the Cucujus beetles. In nearly everywhere we looked, we seemed to find Dendroides in numbers far higher than Cucujus. The collection process is still pretty much the same. Find a fallen tree in the right state of decay and peel away the bark. The larvae live just under the bark.
In just a few hours, we had collected a reasonable number of Cucujus larvae and a very large number of Dendroides larvae. Most of these larvae will be used for DNA and protein studies later in the summer.
Upon returning to the lab, I continued working on some new super-cooling techniques for the lab. Super-cooling is placing the larvae into a tube, which is then placed into a bath and allowed to chill to temperatures well below zero. The point at which the larvae actually freeze is measured and recorded as its super-cooling point. By attempting to alter some of the procedures, we are trying to address an anomaly that we are seeing in the data. Our Cucujus samples seem to be super-cooling at very different temperatures. It would seem likely that individuals from the same population and location would have similar adaptations to their environment. In the case of our larvae, we should expect them to have very similar freezing characteristics. Our data however, is showing that we have distinct differences in the Cucujus population. Most of the larvae have super-cooling (freezing) points near -350C, but yet a significant number of our test larvae have had super-cooling points above -100C. This bi-modal spread in the population is very unusual and very interesting to everyone here in the lab. Before getting too excited however, we must make sure that the result is not due to some problem in our freezing techniques.
Consequently, Dr. Valerie Bennett and I have been trying to devise ways to make the lab procedures as similar as possible to the conditions the larvae would actually see in the logs. Part of my task over the next week and a half will be to test several of our new techniques for their effectiveness and compare the results to those we have seen using the established procedures. Hopefully, I will have contributed something useful to the lab by the time I leave here next week.
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