What kind of caterpiller is this? can we raise it? How?

June 26, 2020 8:25 AM

What kind of caterpiller is this? can my son and I raise it to a beautiful butterfly? How? It's on a spruce tree if that helps.
posted by If only I had a penguin... to Science & Nature (14 answers total)

Looks a lot like a spruce budworm, (google images link) which is a pretty serious pest that can do massive damage during outbreaks. You can probably keep it alive to pupation in a well-ventilated cage in the shade, supplying it with fresh spruce branches and periodic moisture.
posted by SaltySalticid at 8:31 AM on June 26, 2020 [1 favorite]

Response by poster: Hmm...looking at pics of the caterpiller... I think the one I found is more green than brown and the budworm is more brown?
posted by If only I had a penguin... at 8:36 AM on June 26, 2020

Best answer: Could be a Yellowheaded Spruce Sawfly larva then. Sawflies look a lot like wasps, so you won't get a beautiful butterfly at all.
posted by pipeski at 8:50 AM on June 26, 2020

Well, per the Wikipedia article SaltySalticid linked, there are some 40 different species of them, and likely some of those trend closer to the green end of the olivebrown continuum. I think usually caterpillars of that tiny size become small nondescript brownish boredom moths rather than beautiful butterflies. You could probably put it in a jar with holes punched in the top and regularly cut spruce sprigs for it to gnaw on and maybe sprinkle some water in the jar now and then. With luck it would pupate and soon enough you'd have a little moth or wasp-looking fly in the jar.
posted by Don Pepino at 8:54 AM on June 26, 2020

Best answer: If it's a sawfly, you might be waiting quite a while for the adult to hatch: according to this USDA factsheet, they don't hatch out till at least the following spring, and might hang out in their cocoon for a year or two before getting on with pupating.
posted by ManyLeggedCreature at 9:00 AM on June 26, 2020 [1 favorite]

Best answer: Based on life cycle, I think if it's one of these two, it's the sawfly. Whoever it turns out to be, it would benefit that spruce it's on if you were to evict it along with all its friends and family.

https://www.winnipeg.ca/publicworks/insectcontrol/insect/sprucebudworm.stm

http://cues.cfans.umn.edu/old/Web/225YellowheadedSpruceSawfly.pdf
posted by Don Pepino at 9:10 AM on June 26, 2020 [1 favorite]

Response by poster: Ok, I've returned it to its tree. One more or one fewer won't make any difference to the tree, and it feels wrong to take a little caterpillar off it's home and kill it just because. Yeah, that's weird because I'd have no probably with someone spraying down the tree with pesticide, but ethics are funny that way.
posted by If only I had a penguin... at 10:00 AM on June 26, 2020

Best answer: I've uploaded a photo from a book on conifer defoliators that shows identifying features of lepidoptera (butterflies and moths) and sawflies. If you can get a close look at the legs and eyes of this and future finds, you should be able to tell which is which.
posted by bethnull at 10:01 AM on June 26, 2020 [1 favorite]

Response by poster: It's sawfly 1 - no prologs.
posted by If only I had a penguin... at 10:05 AM on June 26, 2020 [1 favorite]

If you want some really nice larva/butterfly babies, try planting some dill or fennel - it attracts a ton of swallowtails every time I grow them. The larva get pretty large, are easy to handle, and the butterflies are lovely. Check to see if they will grow in your region first, of course.
posted by amtho at 10:10 AM on June 26, 2020 [2 favorites]

Nature nerd in here to remind everyone that there is no difference, taxonomically, between butterflies and moths, and moths are equally as important pollinators that come in a variety of colors, sizes, and larva, and sometimes the ugly ones make beautiful friends
posted by FirstMateKate at 11:34 AM on June 26, 2020 [4 favorites]

Seconding the idea to plant some dill. I get lots of Swallowtail caterpillars on my dill plants. I usually raise a few in the house each summer to make sure the Roadrunner that frequents our backyard doesn't eat them all. Give the caterpillars fresh dill to eat until they curl up in their "J" shape to pupate. They will need some sturdy sticks to attach to while they are in the chrysalis phase. Be careful not to crowd too many twigs into whatever it is you have them contained in. The butterflies are sizable and they need lots of free space in which to unfurl their wings. If they can't get enough free space, their wings may not unfold properly, and they will be unable to fly and most likely starve to death when you release them. Never take all of the caterpillars you find. Always leave a few to grow up naturally.
posted by WalkerWestridge at 9:45 PM on June 26, 2020

Funny. Just saw this on digg: https://www.boredpanda.com/tesco-broccoli-caterpillar-sam-darlaston/
posted by terrapin at 10:53 AM on June 27, 2020

HA — a couple weeks ago, I raised a caterpillar I found on my cucumber plant... into a boring moth. but I still found the whole process delightful. we’re in a pandemic, we need all the novelty we can get
posted by changeling at 11:27 AM on June 27, 2020