[Odonata-l] Tail-dipping Female Octogomphus (Grappletail)

[Glenn Corbiere]

Hello Everyone,

What better way to pass a rainy vacation day than pondering the life histories of dragonflies.

It can be extremely difficult to find various life history details on so many dragonflies. It's frustrating looking at old books and finding almost nothing other than descriptions.

After spending an hour or so looking at various refrence works, I could not find any mention of Octogomphus specularis ovipositing by dropping eggs while in flight, at least not exactly. I did find this quote from Clarence Kennedy from an article published in 1917 entitled "Notes on the Life History and Ecology of the Dragonlfies of Central California and Nevada". It describes a behavior not quite what Nick Donnely and Jim Johnson observed, but somewhere between what they observed and dropping eggs in flight.

"After having spent various days wading down mountain streams observing Octogomphus more often than catching them, I was rewarded on July 7 by seeing a female oviposit. She came volplaning down through an opening in the canopy of alders and, while going through evolutions involving several figures, 8's and S's, she touched the surface lightly with the tip of her abdomen at intervals of 2 to 6 feet. After 20 seconds of this she airily spiraled up and out into the sunshine, where she alighted on a bush on the hillside above the creek."

Incredible prose, isn't it? Makes you want to read the entire article. You can find it online in Google Books, which is itself an incredible resource for old books and articles. (Volplaning sent me to the dictionary.)

I've been waiting for some time for a discussion along these lines. Supposedly, the Ophiogomphus clan oviposits in a similar way to what Clarence Kennedy described for Octogomphus.  Believe it or not, the only description I could find about this came from the same 1917 article by Kennedy.

"In ovipositing the female deposits the eggs in swift water, usually on rapids, where she flies back and forth dipping the tip of her abdomen in the stream."

By the way, both of the above quotes are reproduced in Needham and Heywoods' "Handbook of the Dragonflies of North America" published in 1929, the forerunner of Needham, Westfall and May's "Dragonflies of North America", Revised Edition of 2000.

I want to relate what I observed with Ophiogomphus mainensis six years ago. I was at beautiful stretch of the rocky West Branch of the Westfield River here in Chester, Massachusetts. I was watching a snaketail flyh about when to my surprise, it suddenly plunged into the river and started floating downstream on the swift current. I had no idea what was going on here, and thought it was a very strange behavior. The dragonfly floated with the stream between two rocks, and paused there for perhaps a half minute or so, at which time I snapped a couple photos. At that point I could see it was a female. Then the water seemed to win out again, and she continued floating downstream. She washed up against and over/around small rounded and protruding rock, and she held on. The front part of her body was on the rock, her abdomen trailing in the water. I snapped a few more photos before she sprung up and flew on her way. When I looked at the photos later, both
 when she was stuck (or so I though) between the two rocks, and hanging on to the small rounded rock, I could see eggs drifting back from her abdomen, trailing strings. I've had a photo posted on my web site since then, but I sized it up a little for older eyes (not unlike my own). The photo is not as sharp as I would like, but if you look closely I think you'll see an egg trailing from her abdomen:

http://www.dragonhunter.net/ogomphus_mainensis_f_ov_lg.html

What I don't know, since I didn't manage any photos while she was freefloating with the current, but I suspect, is that she was ovipositing during her entire journey on the water.

Every year since I am often in areas with abundent Ophiogomphids of a few different species, but I have never observed this behavior again. I don't know if it is a usual way for them to oviposit, or if this was somewhat of an anomoly. I can only speculate here, but my speculation is that it was not an anomoly.



Glenn Corbiere 
100 Prospect St. 
Chester, MA. 01011-9657 

www.dragonhunter.net 



----- Original Message ----
From: Jim Johnson <jt_johnson at comcast.net>
To: nw_odonata at yahoogroups.com; CalOdes at yahoogroups.com; Odonata-l at listhost.ups.edu
Sent: Monday, July 20, 2009 11:02:51 PM
Subject: [Odonata-l] Tail-dipping Female Octogomphus (Grappletail)

Greetings,

I've been corresponding with a few individuals about this subject, but I
thought the wider community would find it interesting. Sorry for
cross-posting...

A little background: 

First, the Gold Lake outlet/Salt Creek head in the Oregon Cascades near
Willamette Pass harbors a large population of Octogomphus specularis
(Grappletail). At their peak, the density of individuals at the outlet and
immediate area is staggering for a dragonfly, matched in my experience only
in certain circumstances such as heavy migrational concentrations and when
large numbers seek shade in extremely hot, sunny conditions. It really has
to be witnessed to be appreciated. The high density of individuals at this
location in and of itself is very interesting and I'd like to know if there
are other locations with similar densities of Octogomphus.

Second, during the Dragonfly Society of the Americas annual meeting last
year in Oregon, Nick Donnelly visited Gold Lake and witnessed previously
unreported behavior: a female Octogomphus perching on the side of a rock
with only the tip of her abdomen in the water. She appeared to be
ovipositing in this way although the normal mode for this species (and most
gomphids and many other dragonflies) is to drop eggs on the surface of water
while in flight.

Last Friday I visited Gold Lake to photograph some odonates and spent time
at the outlet to see the Octogomphus. I think there were more there than
during any other visit that I have made. I'd say there were easily four
dozen right at the outlet flying around and sitting on rocks and logs, plus
countless more in the nearby parking lot, campground, on the bridge, on my
vehicle, on my hat, etc. Seemed like one or two copulating pairs flushed
from every tree that I walked past. I photographed boulders in the outlet
with multiple resting Octogomphus--the highest number in one shot was 13.

It didn't take long to start noticing females perching on the sides of rocks
and logs with just the tip of the abdomen in the water, just like Nick
Donnelly reported last year. I saw around 15 instances and photographed ten
of them. I have created a page on my web site to display some of these:
http://odonata.bogfoot.net/photo-pages/tail-dipping-Octogomphus.htm . 

I *may* have seen eggs drifting away from the abdomen in one case, but
because of the suspended material in the water flowing out of the lake and
because of the viewing conditions, I couldn't be sure. I don't see any
readily apparent eggs in any of my photos. I observed one female make a
short typical ovipositing flight, tapping her abdomen on the water surface
right after "dipping" from the side of a log. Several times I was able to
predict this behavior when I saw females making low, short, back-and-forth
flights along the side of a log or boulder before she perched on the side.

There are a couple of obvious questions for which there are no apparent
answers at this time:

1. Are these females ovipositing, and if not, what are they doing?

2. Is this behavior a product of living in such high density (e.g. covert
oviposition in order to avoid harassment by the many males nearby) or is it
normal behavior which was only noticed at Gold Lake simply because there are
so many readily observable females in one location?

Dennis Paulson mentioned that many gomphids eggs have threads which adhere
them to the substrate as they drift downstream, and perhaps this behavior is
related to that (loosening up the threads). I was so focused on
photographing these females that I didn't net any of them to see if they
were extruding eggs or not. In hindsight, that would have been a good idea.
There is still plenty of time this season to go back and do that.

Something for those who live near Octogomphus to watch for.

Cheers,

Jim Johnson
Vancouver, Washington
jt_johnson at comcast.net
http://odonata.bogfoot.net/



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