The Belgica Antarctica Uses Antifreeze to Survive in the Antarctic


The largest land animal in Antarctica is an insect, a wingless midge, Belgica antarctica, less than 1.3cm (0.5in) long.

Natural Antifreeze
How does this tiny creature survive such low temperatures, both as a larva, and in its adult stage?

The Antarctic peninsula has experienced warming of 3C over the past 50 years, yet is still an inhospitable place for plant, marine, or animal survival..
 
Even though it`s now reckoned that there are 1,224 species in 50 different biological classes in the Antarctica area, the Belgica antarctica is considered the continent's largest terrestrial animal.

Few terrestrial vertebrates are resident in Antarctica and those which do occur are limited to sub-Antarctic islands. There are no flying insects, they'd get blown away.

It seems that certain creatures in Antarctica have a natural antifreeze that helps them keep moving in cold weather. However, when the temperature gets too low, they freeze and die. The Belgica antarctica is among these creatures which uses the natural antifreeze to keep moving in ordinary cold weather. But when very cold weather threatens, he uses an `anti-antifreeze` chemical to survive. Long before the temperature gets dangerously low, the `anti-antifreeze` stops the action of the antifreeze. 

                                                       

Why does this happen?
Biologist John Baust explains: "By inducing the insect to freeze at fairly warm temperatures, the special anti-antifreeze compound insures that ice forms at a slow rate. At lower temperatures, rapid freezing would remove water from its cells too quickly, and the animal would die as a result." But since Belgica antarctica freezes gently, he survives and simply thaws out when the temperature rises again.

The Belgica antarctica is the only true insect found on Antarctica. It undergoes complete metamorphosis (like many insects), meaning it has a larval and an adult form that are quite different. This insect is amazingly resistant to all kinds of stresses in both its life stages.

Both sexes have slightly lower water content and a higher dehydration tolerance (30% water loss) than most other insects.

The Belgica larva survives freezing of its body fluids.

As the lava needs moisture to survive they cluster together during dry conditions to avoid water loss. In fact the lava survives dehydration to 35% of its original body weight.

The antarctic region has huge variations in salinity and pH levels, yet the Belgica lava is resistant to the swings.

The lava can survive lack of oxygen for 2-4 weeks

Its color is a deep purplish black which helps it absorb heat absorb heat.

The fact it can live for two years allows it two growing seasons in which to accumulate the energy to reproduce.

The Belgica adult is wingless, to avoid being blown about.

It will tolerate relatively high temperatures.

Its life span is around 10 days, enabling it to mate and lay eggs quickly during the highly variable summer months.

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