Acraea asema, commonly known as the speckled orange acraea, is a butterfly of the family Nymphalidae. It was first described by the English entomologist William Chapman Hewitson in 1877. The species belongs to the subfamily Heliconiinae and is part of the large genus Acraea, which is predominantly found in the Afrotropical realm.
Taxonomy
The species is classified within the subgenus Acraea. Like many members of its genus, Acraea asema is part of a complex group of butterflies that exhibit similar morphological traits, which can sometimes lead to challenges in field identification without close examination of wing patterns or genitalia.
Description
Acraea asema typically possesses a wingspan ranging from 45 to 55 millimeters. The wings are characterized by a pale orange or tawny ground color. The upper side of both the forewings and hindwings features a series of small, distinct black spots distributed across the discal and post-discal areas. The wing margins are generally marked by a thin black line rather than the broad black bands seen in some related species. The underside of the wings mirrors the pattern of the upper side but is often paler in coloration.
Distribution and Habitat
The geographic range of Acraea asema is concentrated in Southern and East Africa. It has been documented in several countries, including Zimbabwe, Mozambique, Malawi, Zambia, and central Tanzania. The species is primarily associated with savanna and open woodland ecosystems, particularly miombo (Brachystegia) woodlands. It is generally observed in these habitats during the warmer months of the year.
Biology and Behavior
The larvae of Acraea asema are known to utilize plants in the family Passifloraceae as their primary food source, specifically species within the genus Tricliceras.
In common with other acraeines, Acraea asema is believed to be unpalatable to predators. These butterflies sequester cyanogenic glycosides from their host plants, which serve as a chemical defense. Their bright coloration is an example of aposematism, serving as a visual warning to potential predators of their toxicity. The flight pattern of the adult butterfly is typically slow and low to the ground, a behavior consistent with chemically protected species that do not rely on speed for predator avoidance.