Butterflies of the
Amazon and Andes
Family - RIODINIDAE
subfamily - RIODININAE
Xenandra poliotactis, Rio Alto Madre de Dios, 550m, Peru ©
on a misty August
morning on a river beach on the Rio Alto Madre de Dios, bordering
Manu Biosphere Reserve, in Peru. It is not illustrated in any
published book, so aroused a great deal
of interest amongst the many eminent entomologists consulted in the
course of getting it identified. I'm very grateful to Andrew Neild,
Keith Willmott, Tony Hoare, Blanca Huertas, Gerardo Lamas, Bernard
d'Abrera, Curtis Callaghan and Jason Hall for finding the time to
examine the photographs reproduced on this page.
of us were speculating that this could be an undescribed new
Lepricornis, or possibly even an undescribed genus, but
Gerardo Lamas was the first to suggest that the butterfly might be a
species of Xenandra, and this was later
confirmed by two Riodinidae experts.
Callaghan identified it as
Xenandra poliotactis, and Jason Hall
remarked that in his many years as a neotropical Riodinidae
specialist he had
handful of specimens'. He also noted that 'the dorsal surface
varies slightly from a dull black with
little blue in worn specimens to a
brighter blue in fresh ones'. Bernard d'Abrera
understandably expressed concern that I had not captured and killed
the butterfly and brought it back for study, as it could so easily
have turned out to be a new species to science. It was reassuring
however to be reminded by another friend that it would be against my
nature to kill, and that I should stick with what I enjoy doing most
- studying living butterflies, and using this website to encourage
others to appreciate them as beautiful living creatures.
Xenandra poliotactis, Rio Alto Madre de
Dios, 550m, Peru ©
The butterfly appears to be a female, with the
abdomen distended by the eggs within.
One very notable feature of this species is the
fact that the thorax and
head are devoid of scales except for the yellow-orange
"ruff", and the palpi. When seen in life
this gives the butterfly a very unusual "un-lepidoptera like"
appearance that cannot easily be conveyed in a photograph.
I do not know of any other genus
of butterfly or moth in which the thorax is completely bare.
The butterfly was found on the
shoreline, behind which was lowland tropical rainforest, including
areas of bamboo and secondary growth. Altitude believed to be circa
550m. I found the butterfly just after dawn, and it was extremely
sedentary, facts which combine to suggest to me that it had flown
only a very short distance from its emergence site, and probably
breeds in riparian forest.
was found very early on a cool and misty morning, at a time when other
species were still at roost. It spent several minutes basking on a bit
of driftwood on the river beach. It made no attempt to fly when
approached closely. When I returned to the same spot half an hour
later I found it basking on low foliage about 2 metres away from the
It is possible that the species
only flies on cool overcast mornings, as there was no trace of it in
the vicinity later in the day or on subsequent days when the weather