Eurybia species, probably molochina, Madre de Dios, Peru – Adrian Hoskins
Introduction
There are about 20 Eurybia Underleaf butterflies, which occur variously throughout the neotropics from Nicaragua and Honduras to southern Peru and Bolivia.
All have greyish or brownish uppersides with a series of squarish submarginal markings. Several species e.g. molochina and lycisca have a blue iridescence across the upperside hindwings. Almost all species have a prominent orange-ringed false eyespot in the discal cell of each forewing. Only halimede, albiseriata, elvina and the falcate-winged carolina and pergaea lack these eyespots, and hence are commonly known as “blind” underleafs. In all species the upperside pattern is repeated on the under surface, but the under surface is paler, and the markings less conspicuous.
Other Eurybia characteristics include metallic green eyes and an extremely long proboscis that is almost twice the length of the body, enabling the butterflies to reach deep into flowers for nectar.
Eurybia molochina is found in Brazil and eastern Peru.
Habitats
This species, and others of the genus, occur in primary rainforest at elevations between sea level and about 1000m. They are never seen in open sunlit areas, instead preferring the darkness of the forest understorey.
Lifecycle
I have no data regarding molochina but the lifecycle is likely to be similar to that of other Eurybia species as follows: The eggs are like flattened lozenges and are laid singly on the stems and leaves of Calathea, Ichnosiphon, Maranta, ( Marantaceae ), Costus and Renealmia ( Zingiberaceae ). The larvae are maggot-like, and feed on the flowers, not the foliage. Older larvae can be found in ant nests within sheaths surrounding the stems of the foodplants. They are constantly attended by ants which milk them for a sugary substance secreted from a dorsal gland. The larvae are parasitised by Rogas and other Braconid wasps.The proboscis on the butterflies is very long, and there is a correspondingly long-proboscis casing on the pupa, which extends about 2cms beyond the tip of the abdomen.
Adult behaviour
Eurybia adults are very secretive by nature, spending very long periods resting under the leaves of low growing vegetation, always with wings spread open, cheekily peering out to play peek-a-boo with only their eyes and antennae visible to observant passers by. They are extremely wary and have excellent eyesight. They can detect the tiniest movement and instantly dash out at high speed to investigate any passing butterfly, then almost instantaneously return to resettle under the same leaf, or one very nearby. The degree of agility apparent when they fly into the vegetation, flip upside-down and settle under a leaf is quite amazing to behold.
I have never observed any form of prenuptial ritual in Eurybia species, and assume that courtship is extremely swift and leads to almost instant copulation. I have on occasions found copulated pairs of Eurybia at rest beneath low foliage with wings outspread.
All Eurybia species have an extremely long proboscis which enables them to probe for nectar into the deep flowers of Heliconia plants. The easiest way to observe the butterfly is to find an isolated Heliconia growing in the forest, and to wait nearby until one arrives.
DeVries records that large numbers of Eurybia adults are eaten by Anolis and Norops lizards.