Tuesday, 27 May 2014

Help needed with a caterpillar

I found 2 of these on Bird's Foot Trefoil this evening.  I think they're Six-spot Burnet but can anyone confirm?  Also, could someone tell me the difference between a Five-spot and a Six-spot Burnet caterpillar please, just so I know what to look for.

Six-spot Burnet caterpillar?

6 comments:

  1. Hi Sarah, no cat book with me, but try this link http://www.ukleps.org/Ipadv1.html if you haven't done already that is.
    Best of luck with it...I do find them difficult!

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  2. Thanks Ina. I've checked various websites including the one mentioned. I also have Jim Porter's book but I just don't understand the difference. According to the book, the only differences I can see are size (6-spot 18-22mm, 5-spot 16-20mm) and body colour (6-spot greenish-yellow or yellow, 5-spot pale whitish-green often with a yellowish tint). The rest of the descriptions sound the same to me. Confused!

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  3. We've recently had the same discussion in Glamorgan and come to the conclusion that they can't be reliably separated as larvae.

    George

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  4. Thanks George. I'll just have to see what's flying later in the year....

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  5. Peter asked me to comment, although I don't think I can help with your specific question as I can't tell Five-spot and Six-spot larvae apart either!

    Our problem over here in the Thames Valley has been trying to separate the two five-spotted species. Traditionally we've had nothing to worry about "because we only get Narrow-bordered Five-spot", but over the last few years that's proved not to be the case and some discrete colonies of Five-spot have been now confirmed. The differences appear to be:

    Eggs: 5-spot laid in a heap, NB5-spot in a single layer
    Larvae: 5-spot with shortish hairs, NB5-spot with long hairs (see www.ukleps.org)
    Cocoon: 5-spot 'closer to the ground' (not sure how helpful that is!)
    Adult: 5-spot has significantly greater incidence of combined spots (f. minoides) and in our area they've proved to be the majority at any one site.

    I'm not sure what the five-spotted situation is in Ceredigion, but you could usefully look for long-haired larvae to confirm NB5-spot.

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  6. Thanks for all the info Dave.

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