Biotic hacks

tulip-tree cocoons

An otherwise leafless tulip-tree sapling in the yard still holds five or six leaves, curled and sewn into moth cocoons: a simple yet elegant biotic hack. (Update) This is most likely the work of the promethea silkmoth, Callosamia promethea.

goldenrod bunch gall 2

Many of the dried goldenrod stalks display a more destructive repurposing, the work of a midge known as Rhopalomyla solidaginis which lays its eggs in the terminal bud and restricts all further growth to that point, where its fat larva feeds and may be joined by midges of other species in search of shelter.

goldenrod bunch gall

A inflorescence may still emerge from the cluster, but much of the time there’s only the hack’s faux flower, a beautiful fuck you to the Canada goldenrod.

goldenrod ball gall

Less destructive is the goldenrod ball gall, winter home of a fly larva, Eurosta solidaginis. The adult which emerges in the spring is said to be a poor flyer, and only lives a couple of weeks — long enough to mate and inject its eggs into a young goldenrod stem. It is the larva that then produces the chemical instructions to grow a globular home in the plant’s core.

9 Comments


  1. Stunning photos, Dave, and I’ve learned a few things about those strange goings-on.

    Reply

    1. Sometimes all it takes is the right metaphor. We get college classes up here a couple times a year, and I always struggle to explain galls in language they will understand. I’ll have to try this out on them and see how they react.

      Reply

  2. Martha says something repurposes the leaves of our (indoor) kumquat tree, like that.

    What a great post! Someone on Facebook was asking about magazines to read for general knowledge, and I said, I just read my friends’ blogs, why would I mess with magazines?

    Reply

    1. Thanks, Dale! A real magazine articlewould be rather heavier on solid info, I fear, but online there’s always Google and Wikipedia… Googling “kumquat” and “gall” turns up nothing definite, though it sounds as if there are plenty of citrus gall insects. Since you are well outside the native range, though, it seems unlikely to be that.

      Reply

  3. Very cool- I had just posted about oak galls this week. They’re practically the size of tennis balls…what a strange trick of evolution.

    Reply

  4. Excellent… yes, these are all hacks… taking what was handy and tweaking it to fit new needs.

    And speaking of “hacks”, I saw something else I wanted to pass on… the sensitivity of our senses in everyday terms. I thought of you, because you’re certainly a fellow of poetic sensitivities.

    Reply

Leave a Reply