Naturespeak A naturalist's view of the world

November 10, 2007

The Bald-faced Truth

Filed under: Uncategorized — wykes @ 12:32 pm

   Like pulling a curtain away at a new sculpture dedication, the winds of fall strip the leaves from the trees to reveal their naked form.  This burlesque act also exposes stark evidence that animal tenants have led secret summer lives under the cover of this leafy canopy.  Now empty, the pendulant structures of the Baltimore Oriole and the messy mud remnants of Robin nests stand as proof that these birds once performed their parental duties there. The papery cocoons of the Cecropia Moth and the ball’o leaf structures of the Fox Squirrel promise that life will continue to make use of the supportive branches through the winter.  To most folks, however, the most dramatic revelation brought about by this seasonal event is the exposure of the large gray nests of the Bald-faced Hornet.

   Hornet nests are impossible to ignore (see here).  These basketball sized constructions are built on the peripheral branches of the tree so they are very much out there and “in your face.”  Often these things pop up right in your front yard – overhead and in the very tree that you walked by thousands of times while in daily pursuit of your economic development.  The fact that a thriving wasp colony was pursuing its development in such close vicinity to your flesh can be unsettling, but once the colony is revealed Elvis has already left the building. Should you take the time to cut the thing down, you can treat yourself to a fascinating – and very safe – sight.

  The adult Bald-face is a formidable member of the Yellow jacket genus, but unlike its cousins is primarily black with a prominent white face (see here). Workers will defend their home with great gusto, but are not nearly as aggressive as the black & yellow jackets and generally go about their lives minding their own business. Needless to say, handling an active summer nest is not a good idea.  On the other hand, handling a late season nest after a few killing frosts can be a great idea. The frost kills off every worker (up to 400 per colony) and the place is deserted. Only the queen survives the late season die off. Her royal highness leaves the castle to spend the winter hibernating in a nearby woodpile or under some bark.  She will emerge next spring and begin the process of building another structure. The old house will never be used again.

  The nest consists of an outer shell of homemade paper encapsulating a chamber containing suspended combs.  Take a look here at a cut-away view. Access to the breeding chamber is via an entrance hole located at the bottom and everything is oriented upside down.  The cells are six-sided and the developing grubs cling to their interiors like tiny bats.  Workers feed them a mash consisting of chewed-up caterpillars and spit (sounds good doesn’t it).  New combs are added to accommodate the growing family by hanging it from the previous one with a stout central stalk.  By the time the season ends, many larvae are left to die and their shriveled remains can be seen within.  With each new nursery comb addition, a new outer paper shell is added as an inner layer is dismantled.

  All hornets are skilled paper makers and these black & white wasps are masters of their craft. Everything in the structure is made of paper – true paper.  Wasps beat humans to the punch in this category by well over 100 million years.  Although Egyptians pummeled papyrus into sheets thousands of years ago their product was not true paper.  By definition, true paper requires a chemical interaction between fibers.  The Chinese came up with the process around 100 AD using re-constituted pulp.  For hundreds of years, most early paper was made from cloth materials and had a high rag content. A Frenchman, Rene de Reaumur, observed paper wasps doing their thing and his work led to the development of paper made from wood pulp. 

  Today the average American uses 700 pounds of wood pulp paper and paper products per year (say that three times fast).  All of this paper is commercially made using the same chewed wood and spit (it’s all about the spit) process invented by wasps.  Worker hornets gather wood fibers by chewing away layers from the nearest fence post, dead tree, or porch railing.  The wood fibers are reduced to strands of cellulose and mixed with proteins in the saliva which chemically interact to form a starchy matrix. Each mouthful of pulp is carefully laid down as a crescent shaped addition to the paper shell. Take a look here and you can see the individual mouthfuls clearly indicated by the different colors – the color depending upon the color of the original source wood.

  The paper shell made by the Bald-faced Hornet is layered with air spaces between to act as insulation and climate control for the colony.  Each sheet is only .1 mm in thickness, yet is stiff and resilient enough to withstand the effects of weather long after the colony is gone.  Most of these nests survive winter’s assault and last until the new leaves of spring emerge the following year.  Modern human papermakers would be hard put to make such a durable product today.

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