precious metals

One evening last week, just before sunset, I spotted a bead of molten gold on a morning glory leaf in the garden. Closer inspection revealed a mating pair of Golden Tortoise Beetles (Charidotella sexpunctata bicolor). For once, I didn’t have a camera in hand — I was taking vegetable scraps out to the compost heap — so I returned to the house to get one. By the time I returned, the beetles didn’t seem quite so golden. I wondered how that could be. Had I just imagined them to be pure gold and not tinged with red and with a pair of black dots on the elytra (wing covers)?

I checked Stephen Marshall’s Insects: Their Natural History and Diversity to confirm the ID of these beetles and discovered this comment:

The Golden Tortoise Beetle (Charidotella sexpunctata bicolor, often called Metriona bicolor, 5-6mm) changes color from gold to red when excited. Larvae with their protective fecal parasols, are common on Morning Glory (Ipomoea violacea) and related plants. Pinned specimens of these beautiful beetles undergo a one-way transformation from gemlike specimens to drab pinned beetles as they dry out in insect collections.

Interesting and beautiful, no?!

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15 Responses to “precious metals”

  1. Wayne Says:

    Oh my, that’s really beautiful. There was a moment last spring, with the white-margined beetle, when I thought I had a tortoise beetle, but it was not to be. Quite a coup!

    They’re certainly magnificent enough even if they lost that golden color you saw.

    Also, it’s no surprise at all why they’re named so, is it?

  2. robin andrea Says:

    What a stunning gem of a beetle. Those colors are beautiful, and how incredibly cool that they can change to flaming gold in the heat of the moment. What evolutionary and artful excellence!

  3. Ruhh Says:

    these are splendid! Did you return after leaving them some privacy to find them back to their normal colours?

  4. NIna Says:

    Like little mood rings? (but probably not heat sensitive)

  5. DougT Says:

    Tortoise beetles always remind me of my friend John from Colorado. John is a big chrysomelid beetle expert, and has taught me many. many things about beetle identification. Those are great photos. I’ll be seeing a whole bunch of tortoise beetle species in 3 weeks when I’m down in southeast Arizona. I’ll try to get some pictures.

  6. pablo Says:

    I thought that “when excited” citation would be the explanation!

  7. bev Says:

    Wayne – Yes, aren’t they really quite something? Although very small, they were shining so brightly that they caught my eye from several feet away!

    robin – I love the transformational aspect too. How neat!

    Ruhh – Unfortunately, they had moved off by the time I returned, so I didn’t get to see if they returned to their former gold coloration.

    Nina – Yes, just like tiny mood rings. (-:

    Doug – I didn’t know there were a lot of tortoise beetles in Arizona. I’ll definitely have to be on the look-out for them next time I’m there.

    pablo – The “excited” citation is interesting. Why red? Red for Warning?

  8. DougT Says:

    Bev, it’s the typical tortoise beetle drill down there. You look on morning glories. I typically see the beetles in Madera Canyon and Patagonia. I’m sure they’re lots of other places, too.

  9. Susan Says:

    Bev – your photos are really super. Always something exciting to see! The beetles are just magnificent and your shots really capture the color!

  10. Kelly Says:

    Wow! They look like little jewels, don’t they? I really enjoy your blog, by the way. I’ve been really stressed out lately and for some reason your photos and observations really calm me down :)

  11. Laiku Oh Says:

    Those are really great shots. It is very peculiar to see it change from a gleaming gold to a dark red. Since we’re are in the bug/arachnid category in the post, can you please identify the strange looking spider in this picture:
    I think it’s a white crab spider, but it looks very strange with that white yellow bulge.

  12. Edward Kimble Says:

    I used to keep a fish tank full of these creatures. It was delightful to see them change to drab when my children would try to scare them. The layers of chitin in their wings creates an interference mirror which is altered in its spacing, and hence its color, presumably by hormonal changes. It takes about 3 days to train them that they don’t need to change color when you approach.
    The literature cites a dilute borax solution that can be used to preserve the gold color in death indefinitely. However, my advice is to grow lots of morning glories and yams on your back yard fence and be “vewy, vewy quiet” as you sneak up on them. They also fall to the ground and hide to avoid predators and photographers (unless they are otherwise biologically preoccupied).

  13. bev Says:

    Hello Edward. Thanks for leaving this note. It’s interesting to read that you kept some in captivity for awhile. I’ve had the experience of them falling to the ground, but do manage to get the odd photo. I have a lot of morning glories, so that’s what seems to attract them to my garden.

  14. Scott Says:

    Years ago I was swimmming in Texas and I plucked a lady bug size beetle out of the water…It’s main feature was a gold equalateral triangle which covered most of the shell–the outer egdes were totally was gorgeous… I enjoyed meeting him (or her), but have never seen one since even in all the books I could get my hands on.

    I aslo encountered a moth in my garden in Mexico City that had a body the size of a sparrow, two independent sets of wings, and a see through equalateral triangle on each of the larger sets of wings. I was without film at the time, and gladly let it go…It too I have been unable to find in any databses…

    Thanks for your site…Shalom, HSH

  15. bev Says:

    Scott – The beetle that you found definitely sounds like one of the species of tortoise beetle. There are several with varying amounts of gold and clear areas. The moth you described must be one of the moths that are commonly referred to as hummingbird moths. some of them have areas of the wings which you can see through. I haven’t seen any tropical species, but the ones we get up here in Canada are often mistaken for hummingbirds or very large bumblebees.

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