D. L. from Hong Kong asked:
Hello there I have a question about Cicada's. I have
a big tree outside my house (I live in Hong Kong). The tree is full of
Cicada's which screech seemingly all day and night. I would
like to know why there is moisture dripping from this same tree day and
night. The ground below is constantly wet and there is a definite smell to
the moisture - kind of musty. Is the moisture from the Cicada's and if so what
is it? I have looked at several resources, but found no definitive
answer. Your help would be greatly appreciated.
and we said:
I
think Cicadas are one of the coolest bugs around. They belong to an Order of
Insects called (in most people's book) Homoptera. That technically
means "like, or same, wing," but all of these insects have wings
that form a roof-like shape over their backs. They also have piercing-sucking
mouthparts (my favorite kind!) Aphids, Leafhoppers and Whiteflies are in this
group, too.
Homopterans feed on plant sap. They stick their piercing-sucking mouthparts into
the phloem
(vessels that carry the sugary food fluid of the plant) part of the stem or
leaf. The pressure inside the plant's vessels forces some of the sweet stuff
into the insect's gut - fast. Even though many of these animals filter the sap
twice it is still very sweet, sticky fluid when it is forced out of the insect's
back end.
This stuff is called "Honeydew." It is usually sweet, sticky droplets.
In some places, whitefly infestations can lead to the ruin of the paint on cars
parked under trees. They can be a big nuisance.
Now the truth is that I've never heard of this being an issue with Cicadas.
Perhaps that's why you're having such trouble finding any information! Mostly,
the adults are busy finding each other and mating before they get eaten by birds
or many other predators - they are good eatin'! They don't spend much time
feeding. If the "moisture" you refer to is that prevalent, it is not
likely to be honeydew.
The larvae head straight down to under the ground and feed on root hairs in the
soil. So their feeding would not cause the tree to drip.
See if the liquid under the tree is sticky and sweet-tasting (DON'T EAT A LOT --
Just a little taste... there is some risk to tasting anything you do not know
about, but usually a little taste is safe -- have a lot of water nearby.
Obviously, we do not accept any responsibility if something bad happens if you
do this. If you want to blame it on us DON'T DO IT! Otherwise, it is entirely at
YOUR OWN RISK!)
That would tell you if it is likely to be Honeydew. I do not know anything about
Cicadas in Hong Kong! But, if they live a long time, like on the order of months
instead of weeks, they might feed a lot and then they'd produce Honeydew.
It also is possible that the climatic conditions there just cause the tree to
transpire a lot. Transpiration
is basically the tree sweating. If it is getting a lot of water from the soil
and the air is humid, it will loose water from its leaves - sometimes in large
amounts - to maintain the right water balance. That might be what's happening,
too.
If you want to hunt for more information about Cicadas
(and haven't been there yet) check out:
http://www.zenweb.com/century/cicada/index.htm
If it doesn't answer your question better than I could, it'll at least be a fun
time at their site - it's real cool!
We like to know a little bit about the folks who Ask BUGMAN at the BUGMAN
Educational Entoprises Web site. would you mind telling us a little about
yourself? I think it is very cool that you are writing from Hong Kong! Are you a
student? If so what year are you in? Do you like the Cicadas or are they too big
a nuisance?
Thanks again for Askin' BUGMAN!