Morpho epistrophus argentinus

Is a majestic and large lepidopteran belonging to the Nymphalidae family, easily recognized by its impressive wingspan that ranges from 90 to 110 millimeters. Unlike most of its congeneric relatives known for iridescent metallic blues, this taxon possesses a distinctive pearly-white to translucent pale-blue coloration. The margins of both the forewings and hindwings are adorned with a conspicuous row of circular eyespots or ocelli, featuring dark outer rings, yellow borders, and light-blue pupils, which serve to deflect predatory attacks away from the vital body parts. Its slender body is dark on the dorsal surface and pale grey underneath, complemented by thin, clubbed antennae.

Geographical distribution: This species is endemic to the central-eastern regions of South America. Its geographic range extends across southeastern and southern Brazil (from Espírito Santo and Rio de Janeiro south to Rio Grande do Sul), eastern Paraguay, almost the entirety of Uruguay, and northeastern Argentina, where its southernmost populations are found along the gallery forests of the Río de la Plata in the Buenos Aires province.

Habitat: Primarily frequents gallery forests, riparian woodlands, subtropical deciduous forests, and humid coastal scrublands. It can also be found in mature urban parks, botanical gardens, and ecological reserves where native flora is preserved, requiring microclimates characterized by high humidity, canopy shade, and the strict presence of its specific larval host plants.

Feeding: During the larval stage, the caterpillars are highly specialized herbivores, feeding exclusively on the leaves of host trees such as the coronillo (Scutia buxifolia), the cockspur coral tree (Erythrina crista-galli), and various species of wild figs (Ficus spp.). As adults, they do not visit flowers for nectar; instead, their mouthparts are adapted to feed on fermenting fruits, oozing tree sap, mineral-rich damp soil, and other decomposing organic matter.

Behavior: Exhibits a slow, sailing, and undulating flight pattern, often gliding effortlessly through the forest understory and canopy. It is strictly diurnal, actively flying during the warmest hours of sunny days. The caterpillars are highly gregarious, forming tightly packed clusters on the trunks of their host plants during the day to deter predators and thermoregulate, before dispersing to feed collectively at night.

Reproduction: The reproductive cycle begins when the female oviposits clusters of spherical, pale-green eggs on the underside of host plant leaves. Upon hatching, the highly aposematic caterpillars display striking crimson, yellow, and black patterns covered in urticating hairs that signal their unpalatability. After completing several larval instars, the caterpillar pupates into a pendant, vivid-green chrysalis attached to a branch. Metamorphosis concludes with the emergence of the adult butterfly during the warm seasons of spring and summer.

Conservation status: Although not globally evaluated by the IUCN, local populations are increasingly threatened by habitat fragmentation, agricultural expansion, and the destruction of native woodlands containing their host plants. In some southern jurisdictions, particularly in Argentina, local governments have declared this butterfly a Municipal Natural Monument to secure the preservation of remaining native forests.