February 27, 2012 Buggers!
When I am out on the zodiac with Dr. Amsler's team, we use the call name "Divers" on the radio. I've become accustomed to hearing another group called "Buggers" on the radio and today I got to see firsthand what the "Buggers" do in the field. I spent the afternoon with Yuta Kawarasaki, an entomologist and PhD candidate from Miami University in Ohio. Yuta is studying Belgica antarctica, the largest purely terrestrial animal in Antarctica. Belgica antarctica is a midge, or wingless fly, which reaches a maximum of only 7 millimeters in length!
Larger animals like penguins and seals only spend part of their lives on solid land so they are not completely terrestrial. Belgica has several interesting adaptations to help it survive life in Antarctica. It can survive extreme desiccation, losing up to 70% of all of its moisture, and can survive freezing temperatures that would kill most other related species.
Belgica is a member of the order Diptera, which also includes mosquitoes and flies. They are found only on the Antarctic Peninsula where they live in a wide range of microhabitats from small clumps of grass to mud near elephant seal wallows and penguin rookeries. During their two-year life cycle, the midges spend most of their time as worm-like larvae, which are up to 6 millimeters in length. The larvae eat bacteria, algae and detritus and molt into adults in the summer of their second year. The adult phase lasts only two weeks; during this time the midges mate and lay eggs which hatch after a week.
Yuta is interested in learning more about how Belgica spends the winter in Antarctica. One of his major questions is whether or not Belgica uses cryoprotective dehydration. This strategy involves an organism losing water and drying out in order to lower its freezing point. Yuta is also interested in determining the effects of different microhabitats on the midges’ ability to survive. A microhabitat is the environment immediately surrounding an insect.
At Palmer Station, Yuta works in the Bio Lab Building. As weather permits, he works outside, traveling in zodiacs to the surrounding islands to collect Belgica. I had the opportunity to help Yuta collect Belgica and was interested to see how the collecting process works! We used spoons to collect the midge larve from under rocks, then placed them in Ziploc bags. Lily (the Instrument Technician at Palmer Station) also came along. Between the three of us, we collected hundreds of larvae.
In addition to seeing midge larvae on Cormorant and Christine Islands, we saw several Antarctic fur seals, leopard seals and molting Adelie penguins. Molting involves replacement of feathers in a bird; the old feathers are shed so that new ones can grow in. I noticed many penguin feathers on the ground on the islands we visited today. That was interesting to see!
I didn’t have the opportunity today to see the types of tests Yuta runs on the midges in the lab because we arrived back at the station just in time for dinner. While we were out on Christine Island, a large amount of brash ice blew in which made coming home in the zodiac slow going. I was glad Lily is adept at navigating the brash ice!
Yuta explained to me that in the lab, the larvae are sorted and cleaned. This involves several steps.
Step 1: First the plastic bags containing larvae are put into the freezer. The larvae must be kept cold, or they will die.
Step 2: The substrate (i.e. dirt) containing larvae in the plastic bags is spread over a framed screen, which sits atop a large, rectangular pan of ice and water. A light is then shined directly onto the screen. The larvae crawl away from the warm, bright light, and fall through the screen into the icy water.
Step 3: A pipette is used to suck the larvae from the icy water and to transfer them to a clean beaker of ice water.
Step 4: The larvae are sorted and cleaned again. During the second cleaning, the larvae are transferred into a new container of ice water. This time, there is less dirt and debris.
I hope to have the opportunity to see Yuta’s lab work before I leave Palmer Station. It’s hard for me to believe I’ll be back on the LMG one week from today!