[Odonata-l] effect of rain on ode numbers?

[Sulka Haro]

Hi!

We had a discussion about that back here in Finland after members of the
Finnish Dragonfly Society observed a drop in the numbers after rainy periods
and the general consensus was that if most of the specimens don't get to
feed for an extended period of time due to weather conditions, the numbers
will drop as the dragons simply die off. Does someone on the list have
actual research data on the survival of dragons when deprived of food?
I do recall seeing Aeshna grandis fly in light rain but most species seem to
avoid hunting in rainy conditions.

This year demonstrated the effect here pretty well - the early season was
fantastic and a massive number of the early records were broken. However in
"early mid-season" the weather worsened dramatically for a period of time,
which caused a significant drop in the number of dragons observed. Some
fairly common species suddenly weren't that common at all.

Sulka

On 10/9/07, Chris Hill <chill at coastal.edu> wrote:
>
> Hi,
>
> Here in my corner of South Carolina, it's rained almost five inches
> in the last week, with hard rains on about four days in a row.  It
> turned sunny again yesterday.
>
> How does rainfall like that affect dragonfly numbers?  Does that
> usually knock them down for a while?  I'm asking because I have some
> students doing a research project on a common species, which is
> suddenly less common!  I'd like to be able to guess whether the
> dropoff is weather related and the odes will bounce back, or if it's
> more likely seasonal and they won't be coming back.
>
> CH
>
> ************************************************************************
> Christopher E. Hill
> Biology Department
> Coastal Carolina University
> Conway, SC 29528-1954
> chill AT coastal.edu
> http://ww2.coastal.edu/chill/chill.htm
>
> "Research is just formalized curiosity." -- Zora Neale Hurston
>
>
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