Joseph Johnson asked:

>Hello - I have a quick question about the evolution of the stinger.  Is it
>true that stingers in general evolved from ovipositors?  Can it be said that
>a worker bee's stinger is actually the reproductive system tweaked to
>produce poison rather than eggs and to insert that poison into flesh rather
>than to insert an egg into the ground?  Is the stinger a remnant of a
>sterile worker bee's reproductive tract?
>
>Or did I make this up?


   I won't pretend to be able to answer all that was asked but can provide
some insight.

   Ants, bees, and wasps belong to a group called "Aculeate Hymenoptera"
("aculeate" means sword)  That means that most species in that group have
stingers that evolved from ovipositors.  It also means that one can pick up
a drone honey bee with abandon, since it cannot have a stinger, being a
male (a good way to impress the "tourists" you might have nearby when you
open a hive).

   In other hymenopteran groups females use the ovipositor to inject an egg
into a host --- often a quite an impressive accomplishment.  For instance,
some of the ichneumonflies have very long ovipositors and somehow manage to
drill a hole into a log and place the egg into a larva deep down therein.

   One can see a transition between the ovipositor used solely as an egg
laying device and as a stinger in some ichneumonflies.  When one picks up
one of those individuals, they act as if they are going to sting you.
However, they have no poison sac and usually cannot break the skin.

   While many ant species have stingers (note the notorious "fire ants"),
many other ant species have lost the ovipositor (stinger) altogether and
instead have glands that exude noxious substances.  Some species are known
as "piss ants" because they can shoot a steam of formic acid several inches
straight up at an intruder near the nest.

   However, I cannot comment about the correspondence between the poison
sacs of stingers and where they might have come from.

                                                        Adrian

Adrian M. Wenner                    (805) 963-8508 (home phone)
967 Garcia Road                     (805) 893-8062  (UCSB FAX)
Santa Barbara, CA  93103

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*     "Nature only answers rightly when she is rightly questioned."

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*                                                      Goethe
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