1995-06-04: What's the Buzz? Managing the Insect Population (part 1)

Vol. III, No. XXXII

Transcription:

Jones (VMI)
Day. (VPI)
Grimm (JMtJ)
What's The Buzz?
With Good Reason
Volume III, Number XXIII
Managing The Insect Population
Greeting
They sting, they bite, they destroy. We try to destroy them, yet
insects continue to rank among the globes heartiest creatures.
I'm your host, Lisa Lafata, and this is With Good Reason.
Music
Background
'Tis the season for long days, warm breezes, and bugs. Chances
are good the last time an insect stung you, bit you, or burrowed
its way under your skin, you weren't thinking about those
beneficial properties some bugs bring to the ecosystem. You were
thinking about control. In this program, we're going to address
both of those issues with three experts.
Interview
Lafata
We start now with a chat with Tappey Jones, an associate
professor of chemistry at VMI. He heads a particular area of
expertise we thought you would be interested in, and welcome
Tappey.
Jones
Thank you very much.
Lafata
For anyone who has been bitten by one, the image of a fire
ant is not a very attractive one.
Jones
Right, and their sting is extremely painful.
Lafata
And has been fatal in some cases.
Jones
About .6% of people who are severely stung have a fatal
allergic reaction.
Lafata
Fire ants we know came from Brazil, so when they came to the
United States, probably through the Southeast on a shipment, on a
cargo ship from somewhere, they had no natural predators wherein
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their real home territories they have natural predators. And
that in fact is why they blossomed and went totally out of
control in the U.S.
Jones
That's pretty much true. Also at that time in Brazil there
was not a great, maybe not as great a percentage as there is. here
and fire ants are a field insect.
Lafata
They like the farmer's field.
Jones
They like to be out in the sun. And in fact there are
insects, ant species who live in forests in this country, that
defeat fire ants very well. And you'd never see them, they're
not a pest or anything. So they don't do well in forests.
Lafata
For those folks in our listening area who might want to
identify a colony of fire ants and separate it from other
colonies of ants, give us that rather vivid description of what
the ants look like and how they live.
Jones
The ant nest is usually maybe a foot in diameter and it's a
mound, six or eight inches tall. And it's soft, spongy dirt with
lots of little channels in it. And the nest actually goes down
in the ground six feet or so, and there are two types of red fire
ant. One is where there's one queen per colony and one is where
there are many queens. And the one queen per colony type may
have a quarter of a million worker ants that sting.
Lafata
And hurt badly.
Jones
Hurt very badly. The many queened type can have up to a
half a million, I believe; or more worker ants. And when you
touch this nest, these ants just boil out. It looks like red
velvet because the ants are actually small, just four
millimeters, the worker ants are very small.
Lafata
So they're defending their nests.
Jones
Right. But they're unique in that their venoms are made of
compounds related to ammonia. Most other animals that have
venoms, their venoms are proteins and very much more complicated.
And when I was working at NIH, colleagues of mine had determined
that what was unique about these compounds is how they interacted
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with cell membranes and maybe would have to do with nerve
transmission and things like that.
Lafata
And all of this because there may actually be some
beneficial properties, some medical use for this sometime deadly
venom, is that correct?
Jones
That's true, that's true.
Lafata
What do they foresee? I know it's sometime off in the
future.
Jones
At the present time these compounds are used to study the
most basic cell processes like something esoteric like calcium
channels which are in membranes that have to do with controlling
how a cell in a living system actually lives. And the ants, or
the various ants that I've studied, make these compounds in a
very specific manner, their shape is very specific. And my
colleagues believe that what we have is a handful of keys and now
the trick is to find the locks that they go to. Because fire
ants are generalists. They eat anything, or almost anything, and
they attack anything and they've survived very well, and their
venom is very potent.
Lafata
Yes, too well most would say.
Jones
Too well, right.
Lafata
Well, are we talking about cell reproduction in humans,
cures for cancer or?
Jones
All sorts of things. I don't really know. We have
submitted some to some various cancer protocols at NCI in
Frederick, Maryland. And there was some, there was some semipositive
results. Some others were submitted to the army viral
program, their ant-viral program and that has since been
defunded. But there was some, again, some sort of interest and
results.
Lafata
Well that is fascinating. Kind of if you wait long enough
you may find the good in the bad.
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Jones
That's right. That kind of research takes a great deal of
time. My research is simply to figure out what the chemicals
are.
Lafata
Well fire ants have been here since the thirties. As you
mentioned they are incredibly resilient. There was a time in the
60's, or 70's I believe, they called it the "Vietnam of _
Entomology" when they tried to spray over the entire Southeast to
kill the fire ants. Didn't work, did it?
Jones
It didn't. And it was interesting, the man who named the
fire ant Solenopsis invicta, which means "unconquered", had a
theory that there were these other smaller ants that controlled
the fire ants. And there were two counties in Florida where a
large scale spraying had not been conducted and the fire ants
were actually controlled fairly well.
Lafata
And how did they do that?
Jones .
These other ants live underground and they're called "thief
ants" and that describes how they make their living, they'll
creep into a fire ant nest and take their babies, their eggs and
larvae and all that and just use the nest as a source of food.
When you spray, or even put poison baits out in a large area, you
suppress everything.
Lafata
You kill all the ants.
Jones
And the good ants reproduce much, much less rapidly than
fire ants. Actually that is the problem with fire ants, is how
rapidly they reproduce.
Lafata
Are they still a problem from North Carolina to Texas or
have they passed those boundaries?
Jones
Not yet. And friends of mine in Florida at the USDA station
in Gainesville say that they probably won't, as far as the
Southeast is concerned. The big concern is that somehow they get
transported to the west coast. A shipment of shrubbery or turf.
In this state we had some in Hampton that came from a sod farm in
the Carolina's, I think. Several years ago. And they killed
those and they never came back. Professor Day said they had a
nest in Roanoke that had been there two or three years, but the
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weather prevented the new queens or something from spreading.
It's too cold up here.
Lafata
So they survive better in warm weather.
Jones
Much, much.
Lafata
We know that, and of course the fear of them spreading to
California is that they're a total hazard to agriculture.
Jones
They are.
Lafata
Not just plants, but animals in fact. Been known to kill
livestock even.
Jones
Yes, yes. And they do a great deal of damage to farm
equipment. There are several crops that they're beneficial to,
actually, cotton and sugarcane. But they're not beneficial to
soybeans. Apparently they do a great deal of destruction to the
soybean crop. So, you know, it's not all one-sided.
Lafata
Here in 1995, have any of the modern efforts to control the
fire ant population been any more successful than that massive
spraying back in the 70's?
Jones
Um, there have been, there are new ways to control them.
Things called insect growth regulators and they are very
sophisticated chemicals. And they work fairly well. They
prevent the queen from laying eggs or something like that, from
what I understand. Your other two hosts will know more about
that, but the problem is again, these compounds also do the same
thing to everything else. And the queen has to be fed by
workers, so you have to spread this bait out and they have to
take it to her. And when they do that everybody else, all the
other insects that might be beneficial, and from what I
understand, insects are the best control of insect~.
Lafata
Right.
Jones
They also do the same thing, and they suffer from the
effects of these chemicals.
s

Lafata
Aren't they looking at a parasite, a tiny little parasite
that goes into the fire ant nest and actually feeds on the fire
ants themselves?
Jones
They are looking at that and I think also some fungal and
bacterial type controls like they have for the Japanese beetles.
But that's really not my area of expertise but I've read a few
things that that's so.
Lafata
So for those people who may be tempted to try and engage in
some control on their own, that's not probably the best thing to
do, is it?
Jones
If you're allergic to bee stings or something like that,
this would not be something to mess around with.
Lafata
Is there a method of home control for someone who may_ find
one mound in their field?
Jones
There are all sorts. One of the most cheap is to boil about.
five gallons of water and pour the boiling water on the nests.
And this takes, it's environmentally safe, you just have to be
careful of the boiling water, and the best time to do that is
early in the morning when the queen is up near the top of the
mound.
Lafata
That's great advice.
Jones .
That's a nice technique and that was published, and one
time, it has been used quite a bit actually and it's probably the
best thing for small infestations.
Lafata
Could it be used on other insects as well, just out of
curiosity?
Jones
Sure. Hot water kills insects fine, you boil crabs all the
time.
Lafata
Okay. And on that note, thank you. Very interesting about
fire ants and possibilities of new medical inroads with the venom
that's been nothing but a problem with human kind to date. And
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thanks again to Tappey Jones, associate professor of chemistry at
the Virginia Military Institute.
Bridge
Music-"The Ants Go Marching"