17-6-2016 MONTE CORONA, ADOR - COMMON GERANIUM BRONZE BUTTERFLY (Cacyreus marshalli)

The geranium bronze or brun des pélargoniums in French (Cacyreus marshalli), is a butterfly in the family Lycaenidae.

The geranium bronze butterfly is native to South Africa. The butterfly was first introduced to Europe in the late 20th century, where it has quickly spread to many southern and eastern European regions. Since its introduction to Europe, the geranium bronze butterfly has become a pest to cultivated Pelargonium and Geranium plant species. Currently, efforts are being made to contain the spread of the geranium bronze butterflies as well as to determine the most effective pesticide for the species.

The adult geranium bronze butterfly's wingspan ranges from 15–23 mm in males and 18–23 mm in females. The wings are brown/bronze with a white border outlining the wings. The underside is a grey-brown with darker bands interlaced with white, creating an intricate pattern. The hindwings contain an eye spot in order to divert predators from attacking. The male and female are similar in appearance.

Unfortunately, as pests, the geranium bronze butterflies have caused economic troubles as well. In countries like Spain, the Geranium plant species are highly bought in Spanish homes as ornaments. According to Sarto i Monteys et al., these plants are highly important in both sales and in employment for both production and marketing (Sarto i Monteys V 1991). In Spain alone, there are four major Geranium plant companies, together collecting over $30 million a year in the market. Companies have already seen drops in sales as the Geraniums have been affected by these butterflies. Currently, research is being done to find effective ways to prevent the attacks by these butterflies, but unfortunately many possible insecticides are too chemically potent on the plants that control of these butterflies has been difficult.