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Where did all these mosquitoes come from?
Let’s first discuss mosquito biology.
There are around 54 species of mosquitoes that occur in Texas, and all
require water for the larvae and pupae (immature stages) to develop.
Each species requires specific environmental conditions to complete
its life cycle, however, they can be generally placed into one of
three broad groups:
1. Standing water mosquitoes
2. Floodwater mosquitoes
3. Tree hole mosquitoes
Standing water mosquitoes lay their eggs
in rafts directly on the surface of water. These water bodies can be
lakes, ponds, bird baths and any other permanent water source. The
southern house mosquito is our most common standing water species.
We’ll talk about these again shortly.
Floodwater mosquitoes have developed a
method to overcome droughts. Instead of laying their eggs directly
into water, these females lay the eggs on moist soil above the water
level. And she can lay a bunch of them!
The eggs of floodwater mosquitoes are
quite tough and can resist desiccation for long periods. However, with
the rising water following a good rain, the eggs are submerged and the
larvae hatch in a relatively short period and start a new generation.
This is why we see such a large numbers of mosquitoes in such a short
period of time. These are the little “blood suckers” we are dealing
with at this time. Fortunately, most flood water mosquito species do
not transmit West Nile.
Tree hole mosquitoes are somewhat similar
to the floodwater group but typically prefer small enclosed areas such
as tree holes, old tires, pitchers, flower pots etc. The Asian tiger
mosquito was imported into the U. S., probably in a load of recapped
tires coming from China.
Now back to the southern house mosquito.
The recent rains have flushed our creeks, rivers, lakes and ponds.
However, as these waterways begin to dry up, some of the water will
become stagnate and polluted with decomposing organic matter. This
environment is ideal for the southern house mosquito, which is the
primary carrier of the West Nile virus. Consequently, we will probably
see a shift in species as the summer progresses.
All this information is interesting
(maybe for biologists) but, how we deal with these pesky critters?
First, we cannot kill them all! Some
female floodwater mosquitoes can travel up to 20 miles. So what are
our options?
Everyone knows about bug zappers and
traps that use carbon dioxide to attract the mosquitoes and
electrocute them. These machines attract and kill a variety of bugs
and some of the victims are blood sucking mosquitoes.
However, the research I have seen
suggests that these machines do not significantly decrease the
population, particularly when floodwater mosquitoes are this
prevalent.
Also remember that you are exhaling
carbon dioxide which is a potent mosquito attractant!
The Ultrasonic devices are worthless! Don’t waste your money.
So is there anything we can do?
The Texas State Health Department
suggests reducing exposure to mosquitoes by remembering the four D’s:
Dusk to Dawn: Limit outdoor activities,
particularly from dusk to dawn.
Dress: Wear loose fitting long pants and
long-sleeved shirt when outside.
DEET: If you plan to be outside, apply an
insect repellent to all exposed areas of your body. Look for a product
that contains the ingredient DEET.
Drain: Do not grow you own mosquitoes!
Bird baths, leaking faucets, wading pools, old tires, basically any
place where water can collect and stand, can raise mosquitoes. It is
very important that these sources be drained and, if possible,
removed.
Even with the abundant mosquitoes, I’ll
take a wet spell over a drought…anytime! So the next time you are
bitten, just go in the house, lower the thermostat and look through
the window at all the green grass. |
