Life
is hard for pollinators. Well, life is hard for all creatures, not
just animals but plants, too. They are all food for other creatures.
Leave it to Jonathan Swift to put this concept in a nutshell. He
tells us on Poetry, a
Rhapsody
“...every
creature
Lives
in a state of war by nature...”
And
explains further:
“So,
naturalists
observe,
a flea
Hath
smaller
fleas
that on him prey;
And these have
smaller still to
bit'em;
And so proceed
ad infinitum.”
This is why every
creature needs to invest on defenses in order to survive and to pass
its genes to the next generation. This is also true of pollinators.
We can use bees to illustrate this point, just as Jonathan Swift used
fleas. They have a whole array of defenses, some of them we don't
even know much about. So let us take a look at the better known one,
the stinger.
Bees use their
stingers in self defense and in defense of their brood. They don't
use them for any other purpose. A stinger is located at the rear end
of a bee. It is not like the sharp tongues or jaws of other insects
like mosquitoes, horse flies or fleas. These insects use their
piercing mouth parts for an entirely different purpose, primarily to
obtain nutrition in the form of blood.
 |
Ichneumonid
wasps have an impressive appendage
at
the rear end, but it isn't a stinger.
It is
used only to lay eggs and it is called ovipositor
|
A stinger has a
long and peculiar evolutionary history. Many millions of years ago
there were wasps, ancestors of present day wasps and bees, which did
not have stingers. They did have a long, pointy tube at the end of
the abdomen which they used for laying eggs and got the name of
ovipositor. Many wasps still use it for this only purpose. They
inject an egg inside the body of another insect, for instance a fat,
nutritious caterpillar. The wasp's baby grows surrounded by food and
well protected inside the body of its victim. Ordinarily, it ends up
killing its host. This is why they are considered something between a
parasite and a predator and they are called parasitoids. Their
victims are called hosts.
The hosts, in
turn, developed defenses against their enemies. Many of the larvae
hide themselves inside plant stems or under bark. So the wasps, had
to come up with ways to overcome these defenses. Their ovipositors
became stronger and longer. Other victims were able to fight back by
squirming or biting their attackers back. So the wasps evolved
substances that they could inject along with the egg. These
substances paralyze the victim without killing it. Thus the progeny
has fresh food at its disposal, rather than a decomposing corpse. And
here is where the ovipositor took a curious turn.
In some insects it
stopped being an ovipositor and became a syringe loaded with toxic
stuff. Its function became purely defensive. The wasp found other
means to lay her eggs bypassing the stinger. This happened many
millions of years ago. All the descendants of those early wasps are
what we know as stinging wasps and bees; ants also belong in this
category. They all have a
modified ovipositor which doesn't serve that purpose anymore.
The stinger took
another turn. Bees don't attack prey. Their ancestors used to chase
insects that were feeding on flowers. At some point, they discovered
that flowers' pollen is so nutritious that it was preferable to feed
this to their brood and not bother hunting animal food. In other
words, they became vegetarians. However, they did not give up the
stinger. They kept it for defense purposes. Obviously, only females
have this weapon. Males never had an ovipositor and as a consequence
they don't have a stinger either and can't sting you.
 |
A
bee's stinger is seldom seen.
It is
tucked away at the rear end
|
One wonders why
females have such a formidable defensive weapon while the males
don't. The answer seems to be that males are shorter lived. Once they
have mated there is no further use for them. The females, on the
other hand have to raise a family. They need to defend the nest and
the future generation, not just themselves.
I read recently
that the budget for defense is bigger than all the other budgets put
together, such as all the sciences, arts, education, the environment
and so on. How is this possible? Later on, I thought that we are not
all that different from the rest of the world, and I mean the entire
living world, plants and animals, not just humans.
