Thursday, April 21, 2011

Green Dock Leaf Beetles

I found scores of these green dock leaf beetles Gastrophysa viridula mating on dock leaves in the pastures beside the River Towy near Carmarthen earlier this week. The larvae chew holes on the dock leaves then pupate in the soil. In a good year they can produce three generations.

The beetles have beautifully iridescent exoskeletons which change from metallic green to bronze depending on the angle of the light. A single female can lay up to 1000 eggs. For the males, finding a female to mate with is highly competitive. In the top picture you can see two males confronting one another over a female.....

... and in this picture you can see a startling case of coitus interruptus, where a mating male - still coupled to the female - has been dragged off her by a rival. I thought this sort of thing only went on in the Bigg Market in Newcastle on a Friday night.....

10 comments:

  1. Beautiful little creatures but what a carry on!

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  2. Beautiful little beetles. I must start taking a closer look at dock leaves.

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  3. ... and these ones here in Llanelli were not too far away either! Thank yuo for a fascinating and informative post.

    P.S. We love the NE ~ used to live in Newcastle!

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  4. Like jewels, aren't they Toffeeapple?

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  5. Hi John, I'm on the lookout for their larvae now John - they reduce the leaf to little more than a network of veins

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  6. Hi Caroline, Beautiful countryside you have in South Wales - we are coming down for a holiday as soon as we can arrange it. Really enjoyed a visit to the Welsh National Botanic Garden... best wishes, Phil

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  7. Thank you for the post. I have been coming across these beetles quite a bit these days and I hadn't got round to ID them.

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  8. Hi Blackbird, I've seen them here in Durham quite often - they seem to be becoming more common...

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  9. Glad you enjoyed the National Botanic here in Wales. Guess you might also enjoy Aberglasney (mix of wild and tame) and Dinefwr ... all in the same area, but you may know these. The WWT at Llanelli has much to offer, too - not forgetting Dylan's 'heron-priested shore' at Laugharne.

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  10. Didn't have time to visit the other two gardens Caroline, but something to look forward to on the next visit.

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