From the Evolution Facebook page:
Tiger Beetles: Part 2
Previously we covered how tiger beetle larvae live in burrows, waiting for prey to come by. But what if they need to quickly escape? Being in a hole in the ground is suddenly not such a good move - so they turn to wind and wheels.
The larvae of the Southeastern Beach Tiger Beetle (Cicindela dorsalis media), like all Tiger Beetle grubs, are not built for speed. If a threat approaches their head, they duck down or move their jaws, but when their back half is stimulated they call upon a different strategy - they leap into the air, coil themselves up and spin away to safety. Slow-motion videos showed that the larvae actually co-ordinate their jumps with a gust of wind so they can roll - the first example of wind-powered wheel locomotion.
This wind-powered movement is very effective. In some cases grubs could roll more than 60 metres, at speeds of 3 metres per second - the fastest recorded movement for an insect on the ground. In strong winds, they could roll faster than the research team could run. Wind-powered wheel locomotion avoids the pitfalls standard wheel-locomotion has - other animals that turn themselves into wheels (such as the wheel spider) rely on gravity. Using wind power gives a tiger beetle larva the ability to roll uphill.
It's thought this escape tactic developed to escape parasitic wasps like Methoca, which can slip out of the grub's jaws and dive into the burrow. Rolling is confounded by rough beaches, rocks and ridges, and foot traffic appears to have an disastrous effect on Tiger Beetle populations.
To read the paper on this unique behaviour: http://bit.ly/ev3YeN
Photo credit: Harvey & Zukoff, 2011.
https://phys.org/news/2011-03-scientists-wind-powered-wheel-locomotion-tiger.html
http://blogs.discovermagazine.com/notrocketscience/2011/03/25/beetle-turns-itself-into-a-wheel
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