Friday, April 07, 2017

Under a bark roof

At the edge of the estuary wetlands, a tangle of rotting, winter-felled trees bordered the path. What bark still remained hung loose; I peeled off a section, disturbing a family of sowbugs and an earwig in his bright spring outfit.

The wood is soft and wet, protected from light (up until this moment), warmed by early sunshine; a perfect hangout.

The next piece of bark housed spider egg cases on the underside.

Another earwig. I haven't seen one wearing this beautiful maroon colour before.

More sowbugs with frass.

I was interested in the leftovers, the bits of chewed and/or excreted wood, in various colours, stirred together like a vegetable casserole with a side dish of mashed beans.

Under another slab of bark, I found this beetle:

One of the Jewel Beetles, Buprestidae.* A wood borer, probably a recent hatchling.

(*Update: the beetle has been re-identified as a click beetle, Agriotes lineatus. The following paragraph, then, refers to the photo beneath.)

These beetles lay their eggs under the bark. The larvae hatch and tunnel outwards, eating the nutritious growing layers just underneath the bark. They leave characteristic tunnels, wider at the outer end (because the larva is now bigger and hungrier). They pupate, then hatch into adults, which drill an exit hole out to the big, wide world, and hurry away to find a mate.

Mined log, at Miracle Beach. The long, straight, central tunnel was made by the adult female; each little notch along its edges is where she laid an egg. Several exit holes are visible. Species unknown.

After each photo, I carefully notched the piece of bark back into its original location.


  1. another excellent adventure.

  2. There's a maturation point in many biologists' life when the passion for an organism overrides any preconceived (mostly culturally driven) revulsion of that organism's excrement. Here, poop is compared nonchalantly to human food (casserole?). Do you remember when that happened for you? Was it before or after you started this blog?

    1. Interesting comment!

      Thinking back. Way back; when I was in university, my favourite subject was Microbiology. What I remember most happily of those days were the intestinal worms and their life cycles, often in human feces.

      Back further; I remember "dissecting" cow pies when I was 10. Looking at mouse droppings and gull scat.

      Maybe something was lacking in my enculturation; I was never squeamish.

      Comparing excrement to food? Maybe the first time was on the Boundary Bay beach, looking at lugworm casts and thinking of cake decoration. That was in the early days of this blog.


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