The year of the Dragon Fly?

[mudhook51]

Non scientificly speaking, they are fun to watch. How many nasty biting bugs do you think each one eats in a day?

 

[DougPaul]

Doug
Seems like we are the only two left at the bar talking about this.

It would seem so...

Yes trophic effects are hard to tease out. The species interplay is very dynamic and is loaded with confounding variables. One can spend years doing a study, might answer the orignal question but will produce ten more questions. During a masters course in ecology my prof had a hard time telling me that a regression with an R^2 value of 0.51 was significant. With my line of work anything less then .990 is a bad day. But I am not doing regressions.

One problem with regressions is that they assume linear relationships. While possibly true for small perturbations, many of the relations are nonlinear. For instance, a species cannot have a negative population.

I love the article you posted. That study is very important and shed new light on hunter prey and trophic modeling. The results were than expected.

Actually, Google found it. I just remembered the relation between wolves and aspen in some article that I read in the dim, dark past and searched away. I agree--it is a nice article.

I am sure you are familiar with Macarthur's work on feeding warblers. Different species will feed in different zones on the same tree in order to curtail competion. The same thing happens with diurnal and nocturnal preditors.

I'm not specifically aware of that work, but I am aware that species do a variety of things to minimize competition. (For instance, different species of mosquitoes work different "shifts" to share us humans (and other sources of fresh blood) better... )

Doug

 

[Hikes4fun]

non scientificly speaking, they are fun to watch. how many nasty biting bugs do you think each one eats in a day?

82......

 

[Tom Rankin]

82......

No, 42!

 

[Jazzbo]

My Observations Dragonfiles on summits

We too have noticed unusual numbers of dragonflies on Chocurua short time ago. We were with a large party and we all were remarking on large numbers of dragonflies. I agree with Bikehikefish's observation might have something to do with drought conditions and low water levels in lakes etc. Other notable thing I recall is they were all the same species. Having taken two courses in entymology I have an eye for that sort of thing.

Summits in summer are in general buggy. It frequently seems I don't need bug repellent until I reach the summit of where I'm going.

Long time ago I took a field entymology course where we captured specimens using a variety of traps designed around pre-disposition of insects to head upwards when trapped. In particular we employed a pyramid shaped tent in top of which was a killing jar with puddle of cyanide. On the same trip we hiked up Monadnock where we captured many bugs due to similar effect related to bugs predisposition to go up stuff. Dragon flies are drawn to summits due to same disposition but also because that's where the food is.

I expect summit dragonflies are pretty hard-pressed to return to ponds from whence they came to lay their eggs so maybe it's not such a hot idea for them. Their lifespans are pretty short and they lack a predisposition to go down. Oh well at least they ate like kings before they kicked the bucket.

 

[DougPaul]

Summits in summer are in general buggy. It frequently seems I don't need bug repellent until I reach the summit of where I'm going.

I read somewhere that flying uphill is a strategy used by some insects to find mating partners. Obviously, this strategy enables insects from a wide area to congregate in a small number of spots.

I have no idea if dragon flies use this strategy.


(One could order peaks by the insect collection area to make N-biggest-bug-area lists... )

Doug

 

[forestgnome]

The dragonflies were a subject of conversation on a hike to Mt. Moriah and Shelburne-Moriah. On these summits, and on open ledges along the way, we saw a surprising amount of dragonflies, and they were huge. I tried to get a pic but I coudn't spend enough time...very difficult.

Great thread...love VFTT

happy trails

 

[Paradox]

Riding my bike home from work on Tuesday, I rode through a flock (?) of them about 50' from my driveway.

Does anyone happen to know the collective noun for dragon flies?

 

[Hikes4fun]

We saw a big "flock" of them Monday at Indian Falls

 

[bikehikeskifish]

Riding my bike home from work on Tuesday, I rode through a flock (?) of them about 50' from my driveway.

Does anyone happen to know the collective noun for dragon flies?

A mouthful?

Sorry,
Tim

 

[brianW]

While cutting grass today I was thinking there were a lot of dragonflies out tonight. Than I read this thread. I live close to Augusta, GA. I have a BS in entomology from UMass and have never heard that dragonflies have emergent cycles like cicadas. Is this just the peak time for them to emerge from the naiad stage each year?

 

[Hikes4fun]

Riding my bike home from work on Tuesday, I rode through a flock (?) of them about 50' from my driveway.

Does anyone happen to know the collective noun for dragon flies?

I can't believe I looked this up...A cluster or a flight

 

[cooperhill]

There are hundreds of dragonflies out in our backyard tonight. Amazing to watch or stand in the middle of.