In article ,
"Mary Fisher" writes:
|
| Read an article recently which said that scientists have found aphids
| being taken to the upper atmosphere by thermals freezing and being blown
| a long way before dropping down, thawing and going about their business.
|
| I wonder how they do that. The scientists I mean, not the aphids. ...
|
| I wondered that too but didn't like to show more ignorance than is obviously
| apparent!

I don't know about this case, but there are several ways you can deduce
that sort of thing. One is the distribution pattern of new strains (and
strains of diseases carried by aphids) - which is one reason that I don't
believe that ants are a significant aphid vector. If such things are
carried by that method, they will appear at random locations downwind,
a long way away from the source. If they are carried by aircraft, then
there will be an association with routes. And so on.

There is also the possibility of sampling them by balloon and seeing them
revive as they come down. There has been quite a lot of such sampling
recently, though it wasn't looking for aphids.


Regards,
Nick Maclaren.