Tuesday, November 6, 2012

Mite capital of the world

Maybe you have heard of Churchill, Manitoba. If so, I assume you know it as the world's capital of the mighty polar bear. Far from it! I believe we have to change this. A new study shows that this small town at the tundra-taiga transition zone is rather the capital of mites.

Mites are among the most diverse and successful of all invertebrate groups. They have exploited a broad array of habitats, and because of their small size (most are minute) go largely unnoticed. Many live freely in the soil or water, but there are also a large number of species that live as parasites on plants, animals, and some that feed on mold. There are plenty of them living on the human body. A single hair follicle for example can support a family of 25 mites. Some 45000 species have been described but estimates go as high as perhaps 1 Million species.

Despite their diversity and abundance, mites are rarely included in biodiversity assessments because of serious taxonomic barriers. The status of many species is uncertain and immature life stages were mostly excluded from surveys as they lack diagnostic morphological characters. Aside from these challenges, there is a scarcity of taxonomic experts. 

Back to Churchill. DNA Barcodes for over 6000 specimens revealed nearly 900 presumptive species of mites with high species turnover between substrates and between forested and non-forested sites. However, species accumulation curves estimated to get a sense for the coverage of the sampling indicate that there might be as many as 1200 species living at this remote place thereby rivalling the most diverse of temperate habitats.
I've been up there twice and have watched the polar bears from a safe distance, collected marine invertebrates, fishes, and even insects. Little did I know about this incredible diversity underneath my feet. Next time I look closer!

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