I saw rather few of this species when I visited La Palma in
the spring of 2001 and not one stopped for a photograph. I followed the
individual above for several hundred metres on the S.E. corner of the
island without seeing it even pause, so settled for this awful shot of
it in flight, taken with my video camera. Then, I believed it to
represent a subspecies of Cleopatra, but it has since been the subject
of considerable nomenclatural controversy. There is a complex of
brimstone species in the Atlantic islands, all sedentary and
genetically differentiated from each other, but not obviously so as to
count as different species. Leraut (2016) treats all the Canary Island
taxa, including palmae,
as
subspecies of Gonepteryx
cleobule.
Bozano, also publishing in 2016, considers palmae
sufficiently distinct, genetically and morphologically, to count as a
different species. It is, quite literally, academic. The population of Gonepteryx on La
Palma is an
endemic taxon and must be protected, whether or not it is raised to
specific rank.
Because this is the only brimstone on La Palma, and it flies nowhere
else, there are no identification problems. Typically, the forewing
upperside is a paler orange than in Cleopatra or the forms of cleobule found on
other islands,
and the hindwing upperside shows no hint of orange at all - unlike
typical cleobule.
Neither of these features would be easy to see in a living butterfly as
if one did chance to rest it would do so with wings closed. Unlike cleopatra, but like
cleobule,
the La Palma brimstone is polyvoltine, flying in a successio of broods
throughout the year. The larvae feed on species of buckthorn, Rhamnus.
