Re: RE : [Odonata-l] Texas Dragonfly to identify...

[Joshua Rose]

Cannot speak to the why, but can add North Carolina to the list of  
sites with super-abundant E. simplicicollis, specifically Howell Woods  
in Johnston County. Spent one day there that every square foot of road  
seemed to have one sitting on it; everywhere we drove, we were  
flushing up clouds of them.

I believe I recall Harry LeGrand, a biologist employed by the state,  
relating similar numbers of the species from other parts of the NC  
Coastal Plain, and a notable drought not only of other odonate  
species, but of butterflies as well.

Dennis, did NC ever have massive outbreaks like this when you were  
working in that state, or is this a recent phenomenon?

Josh


On Jul 14, 2009, at 9:09 PM, dennispaulson at comcast.net wrote:

> Glenn,
>
> You spoke volumes when you tallied up those dragonflies. I've had  
> the same experience, once at Fort Bend State Park in the same part  
> of Texas and often in Florida. I couldn't believe that such a nice  
> series of wetlands as those at Fort Bend supported virtually nothing  
> but those two common species. Often Slaty Skimmer, Libellula  
> incesta, is #3 behind the first two in these situations, but far  
> less common.
>
> It may be noteworthy that that rapacious predator Erythemis  
> simplicicollis is one of the most common dragonflies now in the  
> Southeast. It's conceivable that its abundance is the cause of the  
> disappearance of damselflies from many parts of the Southeast in  
> midsummer. I'm still working on that hypothesis. However, Erythemis  
> eats a lot of Pachydiplax too, and that species is still  
> superabundant. The other alternative is that these two species are  
> favored by anthropogenic changes in wetlands, but a lot of the  
> wetlands where they are common seem on superficial examination to be  
> nice habitats. However, perhaps they have undergone more  
> eutrophication than one might think. Why would the larvae of these  
> two libellulids become so common?
>
> Dennis
>
> ----- Original Message -----
> From: "Glenn Corbiere" <gcorbiere at dragonhunter.net>
> Sent: Tuesday, July 14, 2009 6:46:43 AM GMT -08:00 US/Canada Pacific
> Subject: Re: RE : [Odonata-l] Texas Dragonfly to identify...
>
>
> Michel,
>
> I was visiting Texas a few years back on a business trip, I was near  
> the coast Southeast of Houston. I spent an entire day on three  
> beautiful wetland areas. I saw 6,010 (in round numbers) different  
> individual dragonflies and or damselflies.
>
> 5,000 were Erythemis simplicicollis / Eastern Pondhawk
> 1,000 were Pachydiplax longipennis / Blue Dasher
> The remaining 10 were a total of about 6 or 8 other species.
>
> I was not amused.
>
> Be that as it may, you have one very common dragonfly there, and  
> probably the most common dragonfly around any of these parts, but  
> you have one of the nicest photos I've ever seen of that species!
>
> So ultra common or not, Congratulations on a great photo!
>
> Glenn
>
>
>
> Glenn Corbiere
> 100 Prospect St.
> Chester, MA. 01011-9657
>
> www.dragonhunter.net