Ichneumon*

   The other day a friend of mine received a call describing a four inch wasp.  He considered that call an example of a kind of insect "fish story," either an indication of the observer's inability to estimate size or a comment on his veracity.  As it happened, I was able to offer a third possibility: that the observer might even have underestimated the size of the wasp he had observed.

   A few days before this conversation Mrs. John Cottrell of Chaffee had sent me three insects.  I measured them and found that their bodies were between two and three inches long and from those bodies trailed triple "tails" -- actually ovipositors or egg laying tubes -- that were another four inches long.  Stretched out in flight, they would have been six or seven inches in length.

   Mr. and Mrs. Cottrell had found these large insects on the bole of a maple tree next to their home.  She wrote: "They seemed to put their long spine-like tails in a hole in the trunk.  We don't know if they were laying eggs or drinking the sap."  She added that she and her husband "had never seen anything like them before."
 Indeed neither had I.

   The insects were, however, clearly wasps.  Except for their long tails, they looked like larger versions of those paper wasps that build umbrella-like nests under rural porch ceilings and eaves.  They had the same three section body -- head, thorax and abdomen -- the latter two connected by the original wasp-waist, the kind that Victorian women would have killed for.  They also had the same black and yellow markings, long antennae and legs, and dark diaphonous wings.

   It didn't take long to find what they were.  My references identified them as ichneumon wasps, sometimes called ichneumon flies or long stings.  According to Stokes in his "Guide to Insect Lives," the long ovipositor "is used to penetrate through wood and lay an egg in the developing larva of a horntail, a primitive wasp whose larva feeds in tunnels inside the wood" of maple trees.  He continues, "The egg developes in the larva, not killing it until it is full grown.  The wasp pupates in the horntail tunnel and, when an adult, chews its way out through the bark."

   That horntail is called the pigeon tremex.  Its boring further damages already diseased or aging maple trees.

   Stokes then confirms the observations of the Cottrells: "You may even be lucky enough to watch one of the females deposit eggs in a tree.  She first moves about tree bark, rapidly vibrating antennae against it, then stops at one spot and starts to bend her ovipositor up and back toward herself.  When it is looped over, she stands higher and higher on her legs until the ovipositor is going straight into the bark.  Then in some amazing way, she is able to insert it into the tree, possibly taking advantage of cracks."

   Once again I am impressed with how specific are the life styles of insects.  The pigeon tremex bores only into maple trees and the ichneumon wasp is a parasite only on the pigeon tremex.

   In the sense that "the enemy of my enemy is my friend," the ichneumon wasp is clearly on the maple's and therefore our side.  It is one of a wide array of beneficial insects, a solitary wasp that does not bite or sting.  Unfortunately many of our attempts to control insect pests kill more of these secondary -- friendly -- parasites.

   Thank goodness we have insects on our team like ladybugs, dragon flies, praying mantises and especially this giant wasp.


* This column was first published in the August 7, 1995 Buffalo News.