Ask anyone to name an Antarctic land animal, the response most likely will be, "penguin." However, most of the usual suspects — penguins, seals — don't actually live on the continent. They just visit. With the exception of the emperor penguin all species spend most of their lives at sea. Actually, in order to see Antarctica's resident land animals, you have to look through a microscope. The animals that rule Antarctica are rotifers, tardigrades, mites, and springtails possessing a bizarre array of physiological tools and strategies to survive on the coldest, windiest, highest and driest continent on Earth.
Springtails for example are found all over the planet, but those that live in Antarctica have a few tricks to survive the harsh conditions. They can slow down their metabolism to save energy, and shortly before winter, they start to produce glycerol - the very same substance we use in our cars to prevent cooling water from freezing.
Ian Hogg and his team at the University of Waikato have been studying springtails in Antarctica for quite some time and some of their research was presented in Kunming.
They used DNA Barcodes to examine levels of genetic variability within and among populations of five endemic springtail species along a latitudinal gradient in the Ross Sea region of Antarctica. This work represents the first re-evaluation of several areas, including the central and southern Transantarctic Mountains, in almost 50 years. Three of the five species showed high levels of divergence at both small (<15km) and large (>300km) spatial scales. For example, Gomphiocephalus hodgsoni, a widespread and common species showed 7.6% sequence divergence on opposite sides of the Mackay Glacier and >8% when compared with sites near another glacier. The other two species (Neocryptopygus nivicolus and Antarctophorus subpolaris) also showed high levels of sequence divergences despite being more range-restricted.
What are the potential reasons for such high barcode divergences? The colleagues conclude in their abstract:
... glaciation in Antarctica has promoted and maintained the levels of diversity observed among populations of springtails and that isolation has occurred even on relatively small spatial scales. Levels of divergence are likely to reflect the presence of previously unknown or cryptic species and conservation efforts should be directed towards protecting and preserving the biotic integrity of fragmented landscapes in Antarctica.
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