[Odonata-l] Ophiogomphus howei (Pygmy Snaketail)

[Paul M. Brunelle]

Hello All;
    I am working on a report regarding Ophiogomphus howei in Canada, and
would like to get as much behavioural information as I can from others who
have encountered the species in the field. Paul Catling encountered emerging
specimens on the Saint John River in northern New Brunswick in 2002
(Catling, P.M. 2002. Pygmy snaketail (Ophiogomphus howei), new to Canada.
Argia 14(3): 11-12). There are a few other reports of the species from
rivers adjacent to Maine, or within about 30 kilometers of the Maine/New
Brunswick borders.
    I have only encountered howei flying at one site on two days - and I
have been actively looking for it since 1993. During that period I have made
about 800 visits to Acadian (Maine and the Maritime Provinces) rivers and
streams during its flight period (second week of June to about the same
point in August - the latter purely speculative).
    In the regional database there are 81 records of the species - all but 9
of these records are only of exuviae and/or tenerals on their exuivae. Of
the 9 records which mention adults, 5 are of specimens from University of
Maine Orono which may have been collected as tenerals and raised long enough
to appear fully mature (these specimens were regrettably not well annotated,
and we have been unable to confirm them with the surveyor).
    My encounters with flying adults were on June 20th and 22nd, 1999, on
the Machias River, Highway 9, in Maine, where exuviae had been taken in 1996
by Daniel Boland. On June 17th I had collected skins downstream of the
highway bridge but seen no adults (that I was aware of). The river is of
moderate size, with rapids and pools, and appears not to have been impacted
to any significant extent. It has a recorded list of 33 species, some of
which are slow-water species and may not be resident in the river (or may
have larval presence in back-waters and depositional banks).
    I was wading in a large but only knee-deep pool above the bridge trying
to catch what I thought were Gomphus exilis males ripping around just above
the water surface, when a small gomphid flew down from high in the trees on
the bank and began ovipositing rapidly in large circles (2-3 meters in
diameter) near the erosional shore of the pool well below some rapids, but
where the current was strongest. As I approached she rose more or less
straight up and I could see the orange basal wing markings against the sky.
    So I went back to where the gomphid males were flying over the center of
the pool, and succeeded in catching a number of them - most were G. exilis,
but eventually I netted a howei. I found it impossible to tell the
difference between the two species while they flew, but noted that the G.
exilis males were prone to perching on marginal emergent boulders, which I
did not see the howei do (these boulders are mostly light-coloured granite,
and the yellow basal wing markings would have been very evident).
    There were several laying events - all by females who flew down from the
crowns of the marginal trees. Most ended in a male grabbing the female and
flying upwards abruptly, although one pair flew off through the understory.
    I did not see any howei perching on marginal brush, even though I was
searching for other gomphid species in that common context.
    Two days later I returned to the river with Phillip deMaynadier, but in
spite of a great deal of effort in the pool the only howei taken was a male
flying through the parking area towards the river fairly early in the
morning.
    Exuviae are usually taken on erosional banks where the current is strong
- suggesting that they either live in the fast but even current adjacent to
those banks, or that they drift prior to emerging, in which case they would
tend to end up at those banks. They are generally close to the water,
however they can be found up to about 50cm from the water's edge (although
the water level may have fluctuated since emergence).
    Attempts this year to find the larvae in the St. Croix River (which
forms the southwest border between New Brunswick and Maine, and on which
howei exuviae have been collected on the Maine side) by both dip-netting and
snorkeling were unsuccessful, although O. anomalus was found under the
larger rocks resting on the bottom where the general substrate was cobbles.
Further efforts will be made there in late May and early June next year.
    
    So, in my experience, this is a species which is not abundant (based on
exuviae collection relative to congeners), but well distributed throughout
Maine - not often seen at its river habitat, and rather cryptic even when
present.
    
    I would greatly appreciate any information on other's encounters with
the species. All contributions will of course be credited appropriately.
    Records of flight and lifestage, habitat types, and behaviour notes
would be of great interest. If possible, latitude, longitude, and elevation
of the locales of encounter would be very useful in suggesting possible
flight periods across the species' range.
    If you are aware of any publications on the species, I would appreciate
the references.

    Cordially,
    Paul
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Paul-Michael Brunelle, B.Des., FGDC
Consultant in Natural History
6044-1 Compton Avenue, Halifax, Nova Scotia, Canada, B3K 1E7
Phone: 902-423-1845
Email: pmb at ns.sympatico.ca
Fellow of the Society of Graphic Designers of Canada
Research Associate in Zoology, New Brunswick Museum
Research Associate, Nova Scotia Museum
Regional Coordinator, Atlantic Dragonfly Inventory Program
Coordinator, Maine Damselfly and Dragonfly Survey
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