photo (above) 9
Sep 2006 Wagon Caves, Los
|Northern Bluet is a common and widespread
bluet across much
of North America. Its range was once thought to include northern
but recent genetic studies (Turgeon et al. 2005) showed that Eurasian
North American populations separated about 250,000 years ago and should
now be considered separate species. The Eurasian Bluet goes by the name
cyathigerum — which was the name given to the combined group (e.g.,
Manolis 2003) — but now that they are split, the North American bluet
is Enallagma annexum. The photo below illustrates
that an abdomen
can be very flexible (all bluets can do contortions).
photo (above) 23
Sep 2006 upper San Antonio
River, Los Padres NF
photo (below) of appendage: 9 Sep
2006 Wagon Caves, Los
Northern Bluets show a lot of blue, and comparatively little black, on
abdominal segments 2 through 5. This helps separate them from Arroyo
Tule Bluets. All male bluets are best identified by in-hand views of
terminal appendages. The male's lower appendages (paraprocts) are hooks
that are much longer than the upper appendages (cerci; see photo
The cerci themselves have a very tiny hook at the tip — almost too
to be seen in this photo but clearly visible with a 10X lens in-hand —
that separates them from the otherwise very similar Boreal Bluet E.
Northern and Boreal Bluets often occur together on lakes across much of
North America, including California mountain ranges, and hybridization
is known (McPeek 1990). However, the best interpretation of molecular
so far is that these are two reproductively isolated species (Turgeon
Boreal Bluet has not yet been recorded in Monterey
County but it is
to be expected. It has been collected in adjacent San Benito County.
it shares similar habitats with Northern Bluet, it might be found at
same spots. Boreal Bluet has a shorter flight season than Northern:
late April to early September, compared to Northern's mid-March into
Northern Bluets cannot be safely separated from female Boreal Bluets,
in-hand (Manolis 2003). Both species show blue atop segment 8, like
on the photo (left). This photo was taken at over 7000' elevation in
County, California. I think this photo is of a Northern Bluet because
only netted male Northerns at this lake, but it is still just a guess.
I have not yet seen a female bluet of this type (Northern/Boreal) in
Photo (left) 15 Aug 2006 Heenan
Lake, Alpine Co.
Bluet is very common around high-altitude lakes in montane California
2003). In Monterey County it has been found along streams, rivers, and
seeps in the foothills of the Santa Lucia Mountains (map). It probably
occurs on small montane lakes as well, but such lakes are very few in
date the elevational range in MTY has been 1600-3200' elevation
Since it also occurs in Pinnacles National
Monument — in the Diablo
Range of San Benito County just east of MTY — it is probably widespread
in habitat within MTY as well. However, it has not yet been found in
Diablo Range in MTY.
MTY flight dates of Northern Bluet range
from 23 Mar–23 Sep. Elsewhere in California
it has been found mid-March to mid-October (Manolis 2003).
- Manolis, T. 2003. Dragonflies and Damselflies of
California. Univ. of Calif.
- McPeek, M.A. 1990. Determination of species
composition in the Enallagma
damselfly assemblage of permanent lakes. Ecology 71: 83-98.
- Turgeon, J., R. Stoks, R.A. Thum, J.M. Brown, and
M.A. McPeek. 2005. Simultaneous
Quaternary radiations of three damselfly clades across the Holarctic.
Naturalist 165: E78-E107 [electronically published]
Major identification web sites with much information on California
For sites with excellent photos to compare for identification or to
Many of these sites have links to other useful pages. Kathy Biggs's
is particularly useful in her selection of links.
All photos © Don Roberson 2007