Northern Bluets (E. annexum) at Bat Lake, Algonquin Park

[Jon Pleizier]

Hi All,

I recently spent (see wasted) some time sorting through iNaturalist observations of Northern Bluet to try and clear out the not-so-serious identifications (mostly distant cell phone shots without any focus on claspers, let alone any notes on habitat or identification features).

What I was left with were several observations that didn’t have microscope photos of the upper claspers, but were clearly annexum/vernale. Now, there are limited locations where E. annexum is clearly a regular occurrence and one of those locations is Bat Lake in Algonquin P.P. I don’t know how to find publicly-available annual results from the Algonquin ode count, but a few count results postings to Ont-odes by Peter Mills over the years indicates that over 100 are noted there regularly. The count seems to annually fall on dates when both species would be flying. Jones et al. indicates in multiple locations in the book that Bat Lake is a good place to find this species and also that the status of E. vernale is not well known in the park. 

I guess what I am getting at is that I am interested in learning more about what is know about Bat Lake and the occurrence of annexum/vernale bluets at this location. How much study has been done in on the prevalence of annexum vs. vernale at this site? Can one REASONABLY assume that a sighting without microscopic assessment is annexum and not vernale? Indeed, I have visited this location and found multiple individuals of this species group. My assumption is annexum based on the apparent consensus that this species is prevalent at the site, but I didn’t have the means to photograph the upper claspers sufficiently to note the absence of a node on the inside of the upper claspers. Furthermore, in a park as well studied as Algonquin and where a culture of ode-ing is apparent, I would expect that this species grouping would have been well-investigated at this location and that any occurrences of vernale would have been documented in a public site like iNaturalist by now. As of this posting, I see no indication of confirmed vernale occurrences in Algonquin. 

Any insight would be appreciated!

Jon Pleizier