Last spring I posted a rather long discussion of how to tell the various Celastrina species apart here. Well, as we are all becoming aware, the azures are already on the wing (at least, neglecta is), so I thought it might be useful to re-post these helpful notes about azure ID, mostly from the resident guru Harry Pavulaan in posts on washbutterflies and VA-MD-DE Bugs.
>>(Originally posted 2011 March 24)
The Connecticut Butterfly Association web site recently uploaded Lenny Brown’s guide to the Celastrinas occurring in CBA territory. It’s a little clunky (you have to keep tabbing back and forth between the text and photos, for example) but a pretty good description of many of the species we share with CBA. Lenny’s acknowledgments include Harry Pavulaan, and the two Harrys (LeGrand and Pavulaan) have recent notes on Carolinaleps about Celastrina diagnostics for the Carolinas last week as well. See below.
This is also a good time to re-link to Pavulaan and Wright’s 1999 paper on C. idella, which is in the LepLog library.
LeGrand and Pavulaan comments:
>> (LeGrand) Folks:
Now that “Spring Azures” are being reported – this includes “Atlantic Holly
Azures”, it is past time that I send you my copy-paste job of several long
e-mails that Harry Pavulaan – one of the East’s leading experts on azures –
sent to Salman Abdulali, Will Cook, Jeff Pippen, and me about a week ago.
Since we cannot use attachments, the material is included in the body of this
e-mail, below the horizontal line.
The important point to get from this is that MANY if not the MAJORITY of azures
seen in the Carolinas NOW (March) are actually first-brood Summer Azures
(Celastrina neglecta). So, if you are in the mountains and Piedmont, an azure
now could be Spring Azure (C. ladon) or Summer Azure, though not likely
Atlantic Holly Azure (C. idella); azures in the Coastal Plain could be Summer
or Holly, but not likely Spring.
For example, using the notes below, Alex Netherton’s photo today of an azure at
Catawba Falls looks to me like a Summer Azure because of the whitish
underparts. Spring Azure is usually sooty gray below. Check the websites of
Will Cook and Jeff Pippen; I think Harry P. has gone over these with them, and
made as sure as one can be (without collecting them later) of their correct ID.
I have checked all those photos of azures on the Butterflies of America
website, and these have NOT been thoroughly checked, and some are wrong. Don’t
go by these, at least the photos.
COMMENTS FROM HARRY PAVULAAN:
Spring Azure (Celastrina ladon):
Underside: has a very dark gray underside; darker gray [than Summer Azure or
Holly Azure] with a slight brown pigment component; markings being
well-developed and blackish brown.
Upperside: Spring Azure has a haphazard, almost chaotic arrangement of clear
overlaying long scales (over top of the blue scales) so you don’t see neat rows
like in Holly Azure. The key to identifying Spring Azure is that the male
upperside, when viewed at a certain angle to sunlight, exhibits a “greasy” or
milky sheen, and does not have a metallic shine as do the other azures. Here
[in northern VA], Spring Azure females are very violet. The females can really
be violet, almost light purplish sometimes. When you get out onto the outer
[lower] Piedmont and inner coastal plain, Spring Azure tends to be more blue,
Flight appearance: Every once in a while, I’ll see a duller-looking individual
in flight, with a noticeably more “violet” look (not blue). That’s a Spring
Flight timing: [not stated in Harry P’s posts, but starts in March in NC].
Atlantic Holly Azure (Celastrina idella)Underside: very white beneath, and markings are reduced and somewhat blackish.
Upperside: the blue scales are lined up very neatly like rows of roof shingles.
Worn by late April. Holly Azure has whitish veins too [as does Summer Azure]
but considerably subdued. It lacks the strong white veins along the leading
edge of the forewing that characterizes spring form [first brood] Summer Azure.
What is noticeable is the EVEN distribution of white “dusting” on the hindwing
that is common in Holly Azure. (I stress the “even” because summer form
[second and/or third broods] Summer Azure has strong white scaling on the
upperside HW but the white scales are arranged in rays between the wing veins).
Holly Azure females are dull blue, with hints of white dusting.
Summer Azure (Celastrina neglecta)
Underside: Spring form Summer Azure is best described as sort of a very light
steel gray and the marks are well-developed and have a grayish black component.
Summer form Summer Azure is VERY white beneath. What I notice are the strong
dark marginal marks along the hindwing edge. This is rarely seen in Holly
Upperside: Summer Azure has very distinct whitish wing veins along the leading
edge of the upperside forewing. Summer Azure females are generally bright,
reflective shiny blue. David Wright made an interesting observation that, when
compared to our other azure species, the spring females of Summer Azure
actually have a slight green component to their blue color (thus being “azure”)
that is normally not noticed. You have to place a Spring Azure female and
Summer Azure female side-by-side to really see this.
Flight appearance: Summer Azures are bright blue in flight [as compared with
Foodplants (all species)
Spring Azures are more likely associated with flowering dogwood (Cornus
florida) if you can find it. Look for them before the flowers open – just as
the buds are breaking open. Also look for black cherry (Prunus serotina) that
American holly (Ilex opaca) unfortunately, attracts BOTH Holly Azure and Summer
Azure (spring brood). We [Pavulaan and Wright] discovered this after
describing Holly Azure. Holly Azure uses Ilex opaca and inkberry (Ilex glabra)
exclusively in southern New Jersey, from where we described the butterfly, and
Summer Azure does not produce a spring flight, which is both interesting and
odd at the same time. In subsequent years, I discovered a site in Maryland
where Spring, Summer, and Holly azures were ALL using Ilex opaca! What was
odd, and also disturbing, was that Holly Azure had disappeared from that site,
apparently being replaced by Spring Azure and Summer Azure in the holly forests
on the western side of Chesapeake Bay. Then I discovered that Summer and
Spring azures were using Ilex opaca all around the Chesapeake Bay. So it is
possible that Summer Azure uses Ilex opaca down south too but apparently it
does not use Ilex glabra or yaupon (Ilex vomitoria). I seriously doubt you’ll
find Spring Azure on Ilex opaca down there [in NC] but it is possible.
Flight timing (all species)
Your (in eastern NC) earliest azures are certainly Summer Azure (spring brood).
These can emerge in mid-winter, while Spring Azure and Holly Azure do not,
except in March. Holly Azure seems capable of emerging in early March, thus
being very difficult to distinguish from Summer Azure, which emerges in March.
The rule would be: if there is holly (Ilex spp.), it could be either Holly or
Summer azures; if there is NO holly, then it cannot be Holly Azure.
Summer form Summer Azure normally emerges about mid-April in the coastal plain.<<