Euselasia orfita, Rio Madre de Dios, Peru – Adrian Hoskins
Introduction
The sub-family Euselasiinae is confined entirely to the neotropics. There are 172 known species of which 167 are placed in the genus Euselasia. A few are widespread across Amazonia but most are localised and uncommon. The adults are characterised by having large eyes and small palpi. Most species have rounded wings. The uppersides of males are blackish with patches of metallic orange or blue according to species. Females are dull brown above, with patches of whitish or pale brown. In most species the undersides of both sexes are pale, with one or more vertical bands or lines. In several species including orfita there is also a dark ocellus near the border of the hindwing.
Euselasia orfita has a wingspan of about 40mm. The banded underside bears strong similarities to Satyrines in the tribe Euptychiina, but it is unlikely that this is a case of mimicry, because the two groups of butterflies differ in behaviour – Euptychia species tend to have a slow fluttery flight, and settle to rest or bask on low foliage. Euselasia on the other hand have a very rapid hairstreak-like flight and always settle on the underside of leaves. Mimicry would in any case offer no benefit to either Euptychia or Euselasia as neither are believed to be toxic or unpalatable to birds.
There are several other Euselasia species with a similar banded underside, including clithra in which the outer white band on the hindwing is wider and wedge-shaped, and phedica which has the f/w submarginal band incurved as it approaches the costa.
Euselasia orfita is found in Venezuela, Ecuador, Peru, Brazil and Bolivia.
Habitats
This species inhabits lowland primary rainforests at elevations between sea level and about 900m.
Lifecycle
I have no information specific to orfita but the lifecycle is probably similar to that of other Euselasia species : The eggs are frustum-shaped. They are laid singly under the leaves of Melastomataceae, Sapotaceae, Myrtaceae or Clusiaceae. The caterpillars are compact in form and covered in tufts of short setae. In several species they are gregarious and move in a processionary manner. Unlike members of the Riodininae the larvae of Euselasiinae are not associated with ants.
Adult behaviour
Euselasia males are noted for their habit of spending most of their lives hiding under leaves. Some species such as gelanor and angulata tend to sit under the leaves of low vegetation, while others such as euriteus and orfita tend to settle higher up, under the leaves of trees at heights of between 2-5 metres. Often males of several Euselasia species will occupy a particular tree but each species will settle at a different height and fly at a different time of the morning.
Although they may appear to be hiding, they are in fact “perching” i.e. waiting to ambush any other Euselasia that flies past. If the ambushed butterfly turns out to be another male a short aerial battle takes place after which the intruding male is usually ousted, and the conquering male returns to sit beneath the leaf where he originally perched. Perching males hold their wings erect, but often with the hindwings very slightly apart, enabling a glimpse of the metallic upperside.
The flight is rapid and erratic. Males are active early in the day, but females fly and oviposit in the afternoon. Both sexes visit flowers and extrafloral nectaries. The butterflies fly throughout the year but are commonest in the late dry season and during drier periods in the rainy season.