Thursday, August 6, 2009

Happy Arachnids: Meet the Hawaiian spider that will make you smile

Meet the Hawaiian spider that will make you smile

Scientifically, this tiny arachnid goes by the name of Theridion grallator - but it takes little imagination to see how it got its more popular name: the happy-face spider.

Found only in rainforests in the Hawaiian islands, the spiders have a vast range of patterns and colours on their abdomens - yet all come from the same species.

The amazing diversity is due to genetic variations, although the patterns may also change depending on diet.

Happy Arachnids: Meet the Hawaiian spider that will make you smile

Spider View: Scientists think the happy-face spider has evolved its patterns to confuse predators

The patterns may have developed as a way of confusing predators. The moment it takes an aggressor to work out whether the spider is prey or not provides a vital chance of escape.

However, the species, which was discovered in 1973, is now under threat from the introduction of non-native animals to the islands.

The most common form - or 'morph' - is plain yellow and has no smile. But other variations are plentiful - the 'red front' morph pictured here with a cluster of her eggs is the second-most common.

Happy Arachnids: Meet the Hawaiian spider that will make you smile

Happy Arachnids: Some of the patterns found in the species

The spiders are 5mm (less than a quarter of an inch) long and live alone on the underside of leaves - except during their mating season and for the first 40 to 100 days of spiderlings' lives, when they are still too young to fend for themselves.

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