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Winter Stoneflies Still Emerging

4-2-14 stonefly 123It seems early, especially with feet of snow still on the ground, to be seeing insects flying around, but some have actually been present all winter. An order of insects (Plecoptera) known as stoneflies spends its youth (one to four years) living in streams before emerging as winged adults. Some of these species, referred to as winter stoneflies, emerge from January through April, providing food for early-returning, insect-eating migrants, such as Eastern Phoebes, Tree Swallows and Red-winged Blackbirds. Stoneflies only live a few weeks, during which time they mate and lay eggs. Some do not feed, and others consume plant material. Because stoneflies are intolerant of polluted water, if you see one it’s a good indication that the water quality of the stream that it came from is excellent.

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11 responses

  1. Peter Kallin

    And don’t forget that the ones that end up feeding the birds are just the ones that didn’t feed the fish in their youth! In Mother Nature’s world, everyone is someone else’s lunch.

    April 4, 2014 at 11:58 am

  2. Fifi Ball

    I’m confused about your note that stoneflies’ youth is 1-4 years and lifespan is “a few weeks.” Did you mean a stonefly’s youth is 1-4 weeks? Thanks.

    April 4, 2014 at 3:08 pm

    • So sorry! The young (nymph) stoneflies live on the bottom of streams for one to four years, depending on the species. Then they metamorphose and leave the water, having changed into winged adults. The winged adults only live a few weeks.

      April 4, 2014 at 4:49 pm

  3. Bill On The Hill...

    Great shot Mary. Done with the 100 mm macro? I want one!…

    April 4, 2014 at 3:19 pm

    • Yes, Bill, I must say, if I had only one lens, it would be the 100mm macro!

      April 4, 2014 at 4:50 pm

  4. dellwvt

    I love looking under rocks in our local streams in the summer, and finding stonefly nymphs! But I didn’t realize there were some that emerged as adults in the middle of the winter – how amazing! Are mayfly nymphs equally pollution-intolerant?

    April 4, 2014 at 3:20 pm

    • Great question. Yes, because that’s the stage in which they have to tolerate the condition of the stream.

      April 4, 2014 at 4:51 pm

  5. Brinna Sands

    Hi Mary,

    I wonder if you’ve noticed a lot of snow fleas this year? It’s the first year we’ve found them in abundance in the sap buckets. But it’s been a truly peculiar year for sugaring (and weather in general). Usually we begin to hear redwings while we sugar, and woodcocks. But this year, it’s robins!!



    April 4, 2014 at 3:32 pm

    • I’m not sure where you live, Brinna, but here in central Vermont snowfleas have been out every time the temperature has warmed up throughout the winter. Redwings and woodcocks have arrived here recently, as have hundreds of robins seeking all-too-rare bare ground!

      April 4, 2014 at 4:52 pm

  6. Good to know! Thanks for another interesting post.

    April 4, 2014 at 7:34 pm

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