Sunday, May 9, 2010

Stalking Tigers


The crumbling magnesian limestone cliffs along the Durham coast are excellent places to find these tiger beetles Cicindella campestris. There were scores of them running over the rock-falls at the base of the cliffs at Hawthorn Hive today.


Their exoskeletons are beautifully iridescent, shot-through with a purple sheen when the sunlight strikes them and their movements are distinctive too, rapidly running over the soil surface in a state of constant agitation and often taking to the air for short flights when they’re disturbed.




These insects are ferocious hunters, like most ground beetles, running down their prey and impaling it on needle-sharp jaws (double-click bottom image for a better view of these). When she was a child my daughter made the mistake of catching one of these jewel-like beetles in her cupped hands and instantly regretted it when it sunk its jaws into her finger. Twenty years later, she still remembers the pain it inflicted. Their jaws have a very wide gape and these pictures reveal a possible reason - the male uses them to cling onto the female when they're mating, grasping her at the narrow junction between her thorax and abdomen. The jaws of the larvae, that live in vertical shafts in the sandy soil, are equally impressive and are held level with the soil surface, ready to snap shut on any small insect that blunders too close to the burrow entrance.

For some pictures of another ground beetle in unfortunate circumstances, take a look at http://cabinetofcuriosities-greenfingers.blogspot.com/2009/07/food-that-fights-back.html

12 comments:

  1. Coincidence - I was looking at cliffs today too. Didn't see any of these though - great shots of eyecatching insects.

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  2. Lovely iridescence. I wonder how it appears to the tiger beetles?

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  3. Beautiful, beautiful beetle! The Durham coast is lovely. It's ironic that industrial pollution has played its part in the diversity of the wildlife there now. :)

    Has your daughter followed you into a career in Botany?

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  4. I don't think I've ever seen these before Phil.
    Stunning colour.

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  5. Hi Rob., I'd never associated them with the coast before (mostly have seen them on moorland)...

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  6. Interesting thought Wilma, many insect eyes are sensitive to wavelengths we can see but I've never seen anything written on how they might peceive iridescence..

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  7. Hi Keith, apparently most beetles in this family are tropical. .. and it's the sort of colour scheme you'd associate with a tropical insect

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  8. Hi Lesley, no she hasn't gone into a scientific career - although I don't think it was the beetle bite that deterred her!

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  9. Ho Toffeeapple, my daughter gave me a hand-painted tie with tiger beetles on it for a birthday present ..... but the artist couldn't manage the iridescence..

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  10. Great pictures-I noticed these for the first time in my life on holiday on Chesil Beach in Dorset two weeks ago. Hard to photograph-they move really quickly.

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  11. Hi Threadspider, they can be really infuriating to photograph - just when you are about to press the shutter release, they're gone!

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