I am so disenchanted with everything. I hate all the pants. I hate all the shoes. This must be what getting old feels like.
I am seriously about to start rocking sweat pants everywhere I go.
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
Tiger Beetles: Part 1
Picture this: you're a caterpillar, looking for new vegetation to eat. You spy some leaves just past a hole in the ground and make your way over to them. Next thing you know you're being eaten by something so fast you didn't even see it strike.
Tiger beetle larvae have an intimidating appearance, particularly due to their powerful sickle-shape mandibles. After eggs are buried by the female Tiger beetle, the newly-hatched larva begins to extend and improve its burrow. It digs towards the surface, using its mandibles to loosen the soil and its flat head to push soil out of the burrow when it reaches the surface. Each larval stage the larva goes through (3 in total) is accompanied by increasing the burrow. Their flat armoured head helps them blend in with the soil (though they sometimes hide deep out of sight) and hooks on a dorsal hump keep them anchored in the soil. Powerful mandibular muscles give their bite its strength and their eyesight, unlike many grubs, is sharp and accurate.
When something does come near the burrow, the larva launches itself towards it at incredible speed - interestingly, usually throwing its head backwards at its victim. The sickle-shaped mandibles sink in and its prey (sometimes as big as it) is dragged down into the burrow. Larvae have a similar digestive method to spiders, secreting enzymes to break down food before actually eating it. When the liquidized prey has been consumed, any indigestible remains are ejected from the burrow.
Photo credits: Ted C. MacRae (left), Ingo Arndt/naturepl.com (right).
To see larvae attacking caterpillars, click here: http://www.youtube.com/watch?v=zMkEaIZSNDg
http://drshigley.com/lgh/netigers/tiger_biology.htm
http://insects.tamu.edu/fieldguide/bimg129.html
http://beetlesinthebush.wordpress.com/.../anatomy-of-a.../
http://www.buglife.org.uk/.../bugofthe.../Green+tiger+beetle
David Attenborough's Life in the Undergrowth, Episode 4: Intimate Relations.