Monday, August 16, 2010

Giant Weta

There are 11 species in the genus Deinacrida, and they comprise some of the heaviest insect in the entire world. Thanks to their isolation in New Zealand, Giant Wetas (whose genus name means "terrible grasshopper") have grown to sizes of more than four inches (not including legs) and can weigh up to 2.5oz, which is more than a sparrow. The largest of the Giant Wetas is  the Wetapunga ("god of ugly things.") It is believed that Wetas grew so large because they were fulfilling the rodent niche. There were no small rodents to compete with, and no large nocturnal predators to consume them, so they just kept getting bigger.

Image from Department of Conservation
Despite their size, Giant Wetas are gentle, arboreal giants. They are so heavy that they are unable to jump, and they prefer to consume a vegetarian diet. They really don't have any insect predators, due to their large size, though there are several bird species, including Kiwis and Owls, that make meals of them. Giant Wetas have actually changed very little in the past 100 million years, thanks to their remote island habitat. Similar lack of change can be found in the Tuataras, who also maintain primitive characteristics dating back nearly 200 million years.

Giant Wetas are now facing population issues due to the introduction of rats and cats to New Zealand. They are far less common on the large islands than they once were, and have now been isolated to smaller, offshore locations.

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