Switzerland, May 2018
Switzerland, July 2009
Switzerland, May 2012
Switzerland, May 2010
Approximate distribution - taken mostly from Leraut, but including
Switzerland, which Leraut omits. I know from the Swiss DNA
barcoding results that the species flies there, in a ratio of roughly
1 : 3 to the wood white.
This page comes with a strong caveat: I
have no real idea whether the butterflies shown are cryptic wood whites
or
not. The problem is, this species was discovered so recently and is so
similar to its sister species, the wood white (Leptidea sinapis) and Réal's wood
white (Leptidea reali),
that satisfactory criteria for determination in the field have not yet
been established, if indeed they exist. For the same reason, the
distribution, behaviour and ecological requirements of the cryptic wood
white are not well known, though there is much ongoing research.
Examination of the genitalia is sufficient to separate this species
from the wood white but further DNA analysis is required to separate it
definitively from Réal's wood white. I do not practise violence on
butterflies so do not have recourse to either technique!
As a field criterion, it has been proposed that the postdiscal shadow
on the underside hindwing is more curved in juvernica (the cryptic wood white)
and reali (Réal's wood white)
than in sinapis
(the wood white). It is visibly parallel to the curved outer margin of
the wing. That is the chief distinction I have been using in
Switzerland, where Réal's wood white does not fly. Leraut states that
the summer brood of cryptic wood white is ornamented as a spring brood
wood white and that for this reason they can often be confidently
separated. I'm not entirely sure how to apply this - or perhaps all my
identifications are wrong. He also states that cryptic wood white has
much reduced orange on the antennae. I haven't yet got this one to work
either!
By and large, the cryptic wood
white seems to occupy the same kinds of habitats as wood white and use
the same foodplants (various vetches, principally of the genus Lathyrus), though Leraut states
that it is locally less associated with woods. Like that species it
hibernates as a pupa.