Thursday, June 2, 2011

Hemileuca eglanterina - elegant buckmoth

The first adult emerged today from the group of caterpillars I collected last year in the Manastash hills southwest of Ellensburg, WA.  I wasn't sure if they were going to be Hemileuca nuttalli or H. eglanterina, as both feed on bitterbrush and look very similar.  It turned out to be the latter, and I can't wait for the rest of the adults to emerge!  They usually emerge in July and August, so I'm a little surprised that it emerged the first of June, especially since it has been so cool lately.  These moths fly during the day and look like clumsy but fast-moving butterflies when they zip past.  In higher elevations and cooler climates, they usually take two years to complete their life cycle, overwintering as eggs and pupae.  Adults emerging in mid- to late-summer lay eggs that overwinter and hatch in April or May.  Larvae feed for several weeks through the summer, then burrow into the ground and pupate in July or August.  Adults then emerge the next year to start the cycle over again.
Larvae of all Hemileuca species have urticating spines, which means that they emit a chemical that irritates anything that touches the spines, causing an annoying rash or stinging pain depending on the level of contact.  The pain can last up to a half hour (personal experience!).
Here are photos of the complete life cycle of the Elegant Buckmoth, Hemileuca eglanterina.  The eggs are from a female I found several years ago (she laid them on the inside of the cage zipper!), the rest of the photos are of the group I found last year, ending with the adult male that emerged today.
Hemileuca eglanterina eggs


3 comments:

  1. Nice documentation of one of my favorite species!

    I currently have some eglanterina on the go in the form of a dormant egg ring awaiting warmer weather.

    The final instar larvae of yours are quite a bit darker than what we have here in B.C.
    Ours have mostly burnt orange spines while yours almost look like hemileuca nuttali larvae.

    Cheers,
    Steve.

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    Replies
    1. Thanks for the comment, that's interesting about the color difference in the larvae, but not surprising considering this genus seems to have a lot of variability. I love rearing them even though only about half the pupae survive to adulthood. All the photos I've seen of eglanterina larvae look different than mine, I've reared them three times (this group from central WA and twice from near Tonasket, Okanogan County) and they've always been solid black with rust-tinted spines, and they eat everything I've given them except willow, surprisingly since that's supposed to be one of their main foodplants. They seem to prefer bitterbrush and snowberry, but will also eat serviceberry, and the same larvae will willingly go back and forth between all three. I've also found a couple larvae on wild rose and switched them to snowberry.

      Caitlin

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    2. Eglanterina here do almost eat anything. 2 weeks ago I brought 3 of my ova indoors and they hatched after only 4 hours at room temp!
      I have them feeding on blackberry of all things. Anything in the roseacae family seems to keep them happy. Hardhack (spereyia) is a host Ive used with great success in the past with no losses, provided they get lots of warmth and sunshine. Your adults look similar to mine, which were collected as a larval mass at Shuswap, North Okanagan B.C.

      I also had many losses with pupae in the past, but I think I have them figured out now. I keep them in a cardboard box with holes poked in all sides and them fill it with moss. They are left on my sheltered balcony over winter. the only maintenance I do is to sprinkle a little water in with them about once every 2 months to keep things from drying out too much. Last season I managed to get them all through.

      Cheers,
      Steve.

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