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.
Description
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. It was accidentally brought to Europe in 1978. The geranium bronze butterfly now has established colonies in Belgium, Germany, the Netherlands, Italy, France, Greece, Malta, Spain, Portugal, southern Switzerland, Slovenia, Croatia, and the French Mediterranean. The first record of the species in Palestine was made in the garden of the Palestine Museum of Natural History.
Food resources
Caterpillars
After hatching, the geranium bronze larvae feed on the flower buds, young leaves, and soft stems of their host plant, typically from the genera Pelargonium and Geranium. In order to eat the stem of these plants, the larvae drill into the stems, causing damage to the plants.
Life history
Egg
Geranium bronze eggs are small with a slight green color that turns white then brown or light-yellow before the larva hatches. The eggs are 0.5 mm in diameter and 0.3 mm in height. The eggs are typically laid close to the flower buds, but are occasionally laid on the leaves. The laying of eggs usually occurs during summer months, while caterpillar activity has been recorded in the summer, fall, and winter.
Geranium bronze have spread from their native regions of South Africa to numerous southern and eastern European regions.
Predators
The geranium bronze butterfly has not been reported as a pest in its native home and surrounding South African regions. It is believed that the butterfly has not become a pest in the South African regions because of an indigenous predator or parasitoid that has kept the butterfly population low. The predator has yet to be identified.
References
- J. Kleinekuhle: Zur Indigenität und Ausbreitung des afrikanischen Bläulings Cacyreus marshalli in Südeuropa. Atalanta 26: 209-214, 1995
- J. H. R. Thiele, W. A. Nässig: Der Pelargonienbläuling auch in Deutschland. Nachrichten des Entomologischen Vereins Apollo, Frankfurt am Main, N. F. 20 (3/4): 290, 2000
- Tom Tolman, Richard Lewington: Die Tagfalter Europas und Nordwestafrikas Franckh-Kosmos Verlags-GmbH & Co, Stuttgart 1998,
- G. Tiberglien, « Les Lycène des Géraniums, Cacyreus marshalli : état 2002 d'une espèce invasive », dans « Bull. Soc. Sc. Nat. Ouest Fr. N. S. », n° 24, 4, 2002 (p. 205-214)
- Sarto Monteys, V., 1992. Spread of the Southern African Lycaenid butterfly, Cacyreus marshalli Butler, 1898, (LEP: Lycaenidae) in the Balearic Archipelago (Spain) and considerations on its likely introduction to continental Europe. J. Res. Lepid, 31(1–2), pp. 24–34. Available at: <nowiki>http://lepidopteraresearchfoundation.org/pdf/pdf31/31-024.pdf</nowiki> [Accessed October 4, 2017].