Just relaxing

Finally getting around to spreading some Acronicta specimens I collected in Arizona this past August at the Southwestern Research Station. Time flies when you have tons of busy-work and no time to focus on your own research ideas. Ha!

For those who don’t know, spreading moths and butterflies is tricky business. It takes a lot of skill and practice, and your success depends on several factors: how shaky your hands are (one of my friends drinks a ton of coffee and then complains about how difficult it is to pin her insects), how fresh the material is, the size of the specimen, and how strong the wing muscles are. Learning good technique from an expert is recommended (my advisor is one of the best!).

Freshly killed specimens are the easiest to work with, especially when you are dealing with micro moths – they can dry out in a manner of minutes. Thankfully my moths are measured on the order of a few cm instead of a few mm. If you have to let your specimens dry out first you can leave them in an envelope in a freezer, or you can field pin them, like in the photo above. Just leave them in their normal resting position. Then if you want to spread them, you need to create a relaxing chamber. I accomplish this with a series of tupperware containers and paper towels soaked with water. A tightly sealed lid keeps in the moisture.

The length of time varies, you want to wait until the insects are pliable again. If you are too anxious and take them out early, you will be snapping off wings and legs. If you wait too long, the specimens will start growing mold. I usually wait a day or two, and test them by gently nudging the antennae. When the antennae are soft, they are probably ready to go.

I think I’ll take some in-progress photos as I pin these to share some of my techniques. I have been pinning leps since I was about 10, and it is one of my favorite mind-numbing activities.


Posted on February 16, 2012, in Acronicta, Acronictinae, Invertebrates, Lepidoptera, Noctuidae. Bookmark the permalink. 3 Comments.

  1. When I want to determine the gender of a juvenile birdspider, I wait for them to moult. Then I spread the exuvia and look for presence or absence of the spermatheca. Most of the times the thin exuviae are already too dry to unfold them (or completely chewed into a ball by the spider). Then I let them float on a water filled bowl and put it in the microwave for 5 seconds. Then they are soft and easy to lay out flat. (And easy to tear, too :-/)
    I’ve got no idea if it would work for whole specimen.

    • Yeah I think that would be a little much for a specimen with scales and such. I did unroll a snake skin in a similar manner once, soaking it in warm water and bit-by-bit peeling it apart to stretch it back out.

  2. Brigette was taught pinning and spreading as an infank!

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Ryerson Lab

Functional Morphology, Sensory Biology, Behavior, Biomechanics

I spell it nature

Trying to make sense of the world through science and language.

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