We look at bugs underground

Hello it’s Georgia, Owen, and Professor Urcuyo coming at you from the great caves of Pennsylvania. In our lab we are working on creating an inventory of the invertebrates inhabiting local caves in Franklin County. We collect the samples ourselves during our caving trips and then bring them back to the lab to sort, photograph, and identify.

Before our first caving trip at Carnegie Cave…

and after!

With low levels of light, coldness, and lack of cycling nutrients, caves are a difficult environment to inhabit. Besides the entrance, you soon find the only source of light is the one from your headlamp. Caves remain at a constant temperature and are typically around 52˚F in PA. There is no presence of primary productivity, so the only available nutrients come from anything entering the cave and the water that resides. Some of the passages in the cave can drop as short as a foot tall and are quite difficult to get through. There can also be pretty deep water that accumulates inside. Some passageways can become flooded sectioning off portions of the cave.

Flooded passage

Along with trapping invertebrates inside the caves, we also collect data on temperature and humidity in the back, middle, and entrance of the cave.

“If you see a raccoon in the tunnel, just get on your feet and hands and let it crawl under you”

–Ish

All of us are working together to identify our samples to the lowest taxonomic level, we’ve split up our preliminary research but otherwise we all have the same role in the lab.

Hey it’s Georgia and I’m focusing my research on Collembola. Collembola, otherwise known as springtails, are small jumping hexapods estimated to have 50,000-65,000 species worldwide. They typically range from 1-5mm long which makes them difficult to sort from sediment and to photograph under the microscope. I also control the lab music which is super important (default to Big Booty Mix 15 if we really need to focus). I really enjoyed my first experience caving and I can’t wait to go back. I’ve done some pretty intense hikes with climbing and cave like passages but I’ve never experienced something like this before. Professor Urcuyo had us lay down and turn off our headlamps at one point in the back of the caves and it was surprisingly peaceful. It was crazy to experience darkness like that, I couldn’t even see my fingers an inch from my face.

The largest collembola on the left is around 6mm long. The two to the left are in the suborder Arthropleona while the one to the right is in Symphypleona.

Owen here, I am focusing his research on the order Coleoptera (beetles), in particular the superfamily Staphylinoidea which describes over 70,000 species. The size of these rove beetles make them much easier to find and study, however the little details on morphology can be hard to discern. Based on our time slaving over dichotomy keys, we think we have found the genus Philonthina and Quedius and we’re hoping to send off a few of our samples to entomologists to analyze our findings. You’ll often see me modeling in the cave passages, when not distracted by the beautiful iridescence of rove beetles. Our first experience into the caves was quite something…cold, wet, muddy, and cramped. As a bigger individual I was often hunched over and I struggled to get through small crevices, it was quite exhausting. Regardless, all of these factors were worth it. Having to explore an area that has not been touched by many people is exhilarating. In the dark you’ll never know what to run into or what’s around the corner, and that’s the best part.

A beetle found in Carnegie Cave that we identified down to the genus Bisnius. This sample is around 1.5cm. Notice the iridescence on the abdomen and elytra.

Figuring out what we have collected is quite the project. Owen and Georgia have gotten very good at finding articles with original descriptions (some dating back to the 1800’s) and keys that allow us to identify our organism. The keys can be very particular and the genus differentiation can come down to something seemingly meaningless like whether or not the beetle has hairs between its tarsal claws. We have to go to our maximum magnification to look at certain morphological features and so for the collembola (which are much smaller than the beetles) we are considering using electron microscopy.

Along with the beetles and springtails we also have plenty of yet to be identified millipedes, gnats, flies, crickets, and other invertebrates.  So, the rest of the our research summer is going to be busy.

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