Bizarre Tremex behavior??

[Ken Kinman]

Bill,
     Yes, at least one specimen was collected (removed from the horse's
hide).  This was by a concerned horse-owner (in Canada) who posted a
photograph to sci.bio.entomology.misc, and both I and a professional
entomologist (from Florida) agree that it is Tremex (or something very
close).  To me it looks like Tremex columba, but perhaps there are other
species which look similar.
      The Canadian who collected it thought that the wasp was sucking blood
from the horses, but it is clearly an ovipositor.  I suppose blood would get
into the ovipositor in the process.
      Anyway, I have not yet been able to find any literature on horntail
wasps (Siricidae) trying to "oviposit" their eggs into a horse (or any other
animal, for that matter).  I find this interesting, trying to figure out why
such drastic "host-switching" (animals instead of trees) would occur.  Lacks
of appropriate trees?  Pesticides or genetic defect affecting the brain of
the wasp (i.e., "mistakes" a horse for a tree).
      If this occurrence is scientifically documented (it was posted by a
concerned horse-owner, not a scientist), I guess there could be a number of
reasons that this might occur-----especially these days as mankind continues
to disrupt natural ecologies in so many different ways.  Or perhaps this
does occur naturally if a horse rubs up against a tree and thus "smells"
right to the mother wasp.  I can only speculate, but this is just so odd
that it really caught my attention.
            ------ Cheers,
                         Ken
*****************************************
>From: Bill Shear <wshear at email.hsc.edu>
>To: Ken Kinman <kinman at HOTMAIL.COM>,Taxacom <TAXACOM at USOBI.ORG>
>Subject: Re: Bizarre Tremex behavior??
>Date: Wed, 04 Sep 2002 12:51:42 -0400
>
>On 9/4/02 10:37 AM, "Ken Kinman" <kinman at HOTMAIL.COM> wrote:
>
> > Dear All,
> >    This isn't taxonomic, but since there are a number of entomologists
>on
> > the list, I thought someone might know something about this.
> >    Tremex wasps normally lay their eggs in soft or rotting wood, but a
> > person in Canada reports that these horntail wasps are attacking
>(inserting
> > their ovipositors) in the haunches of their HORSES.  Has anyone here
>ever
> > heard of such a thing in Tremex or related wasps?
> >    The wasps were firmly attached to the horses, not just buzzing around
> > them.  Why would a horntail wasp do such a thing, and would its larvae
> > successfully parasitize and emerge from a horse or any other mammal?
>
>Of course the first question is, does the Canadian person really know
>Tremex?  Is the person an entomologist of any kind?  Have specimens been
>collected?
>
>Bill Shear



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