At 05:39 PM 12/8/01 +1100, you wrote:
>Marty the Yellow- tailed Black-cockatoo in Australia listens for grubs
>boring in living trees. When a bug is found they gouge a piece out of the
>tree and stand on it like an old time logger while they continue to gouge
>away the wood until they get the grub.
>Like the theme you started including the leg pulls.
>
>Cheers. Stuart.
Stuart:
That's great. I love to hear about real predator prey sensory
communications, regardless of sensory mode. The most amazing thing I have
witnessed along these lines, made it hard to credit my senses. I used to
teach High School in Watertown, MASS,
and one day in the school yard (late spring?, no notes) a huge limb, mostly
alive, fell off a maple (Norway?, Acer platanoides) and landed on an
(empty) run-around. The pre-school teachers called for a biologist, for
clearly when you have healthy tree limbs (NOT dead) threaten kids in a
playground it must be a biologists field of study, if not their actual
fault. Within ten minutes, as we examined the limb, two things became
obvious: it was full of some kind of large grubs (beetle larvae or pupae, I
was so busy I took no notes) and the largest Ichneumons I have seen
appeared "from nowhere" and began laying eggs in these grubs. By 1/2 hour,
many dozens of these 4-6 cm Hymenoptera had come and gone. These "wasps"
had the typical ovipositors, longer than the body length, and I surmised at
the time, that they had been flying around, looking (smelling?) for the
scent of these wood-borers in the target trees, and that, had not the limb
fallen off, exposing the grubs fortuitously to the air, these wasps would
have had to go the usualy route, penetrating many mm of healthy wood to
place their eggs in the tunnels of their victims.
I have always wondered what sensory modality attracted these
predator/parasites*, and have always supposed most likely olfactory. I
wonder, Stuart, if odor has been ruled out in the case of your Cockatoo,
and if so, how did they do it?
* When I left college, we had no classification to describe the species
interactions like this: a large adult female approaches (and if necessary
subdues or paralyzes a living insect, laying one or more eggs inside the
target species, which then serves as living food (paradise) for the larvae
of the predator species. Or is it a parasite? Of course there are
thousands of examples and variations among the Ichneumonoidea
Superfamily. Evolution of the stinger in the Order Hymenoptera is thought
to have proceeded from this (undifferentiated) solitary egg laying, to
paralytic and egg laying, to the more familiar poison specialist females in
the (more differentiated) social Vespoidea and Apoidea, many of whom never
use the ovipositor for eggs. But I
admit to being forty years out of date, here.
my very best,
Marty Michener
MIST Software Associates
75 Hannah Drive, Hollis, NH 03049
coming soon : EnjoyBirds bird identification software.
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