Subject: A bit of a quandary (controlling mosquitoes and infecting kids)
Date: Apr 17 09:43:48 2004
From: Stewart Wechsler - ecostewart at quidnunc.net


Ron McCluskey, Cheney, WA wrote:

"I hate mosquitoes. And now, with West Nile Virus headed our way, I want
them around even less. So, what to do? I'm considering are bat houses... I
have seen 2 patients in the emergency room in the last year that have been
bitten by rabid bats"

Ron and all,

I've never heard of a bat, other than vampire bats in South America, biting
a person that didn't try to handle them. I imagine that if you handled a
baby bat you could get bit by the mother too.

Consider instead the following mosquito control method:

Though the probability of it noticeably cutting your mosquito population
down by the following method may be slim, I recommend following method: Get
a bunch of butterfly nets and take groups of neighborhood kids (including
some that might be left out of other activities) out to some ponds away from
your presumed mosquito ponds and catch as many damselflies as possible and
release them by the ponds that you suspect to be the source of your
mosquitoes. I believe damselfly nymphs are one major predator of mosquito
larvae. (Dragonfly nymphs may eat more damsel fly nymphs than mosquito
larvae.) Stoneflies and predatory diving beetles are also among those that
I presume eat mosquito larvae.

Remember that the winged mosquitoes, that we think of when we think of
"mosquitoes", are just the flying sex machine stage of an organism that
spends most of its active life as a "larva". The same is true for most
insects. We need to think more about who eats the more abundant larvae than
who will eat the adults that may have already mated or laid most of their
eggs.

I don't know if it would be wise to introduce the damselfly nymphs to the
ponds. The water you would get with them from other ponds could contaminate
the ponds you pour it into with some organism that might upset that pond's
ecosystem, though I suppose the risk would be lower if you rinsed them with
(ideally de-chlorinated) tap water first. Young Long-toed and Northwest
Salamander larvae (genus Ambystoma - Mole Salamanders) also eat mosquito
larvae, but introduction of these species to your ponds (if they're not
already there) might involve other more complicated ecological issues.

Together with the same kids you could run dip nets through ponds and look
for aquatic insects a little bigger than mosquito larvae with pincer-like
mouth parts. (These are the carnivores.) Then put them in in a tray or cup
together with mosquito larvae or other similar sized fly larvae (e.g."
bloodworms" or phantom midge larvae) and see if they eat them. I've watched
damselfly nymphs eating phantom midges in trays in the pond nature programs
that I led for school and general public groups at the former Camp Long
Nature center in West Seattle. We also saw Dragonfly nymphs eat damselfly
nymphs in those trays. The kids loved it!

Be aware that the kids involved may become infected, but not by the West
Nile Virus. You may infect them with the bug for nature, which I believe
might be the biggest key to protecting the natural environment that we all
love.

While I'm sure West Nile is a real problem, I suspect that those who want to
promote fear in our society, and to exploit that fear, may have used the
media to blow it out of proportion. In this climate of fear those who
exploit the environment and people seem to get away with more. Being
anywhere near a car or on a road is certainly more dangerous.

One butterfly net source is Bioquip, but their website has been down for
about a week or so.

Stewart Wechsler
West Seattle
mailto:ecostewart at quidnunc.net

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