Euploea core corinna (W.S.
Macleay) (Common Crow, Oleander Butterfly)
Interesting aspects: These butterflies normally have a slow undulating flight, typical for butterflies with toxic (unpalatable) properties, but when alarmed can make off with rapidity. The butterflies acquire their toxicity through their larvae, which retain the toxins after eating the poisonous hostplant. The butterflies can obtain further toxicity by sucking (imbibing) poisons through their proboscis (mouth part), either from the flowers or sap (from wounds) or bark of its larval hostplants, or even from other poisonous plants like Heliotropium. They can even regurgitate dissolving fluids to aid in the process. They serve as models for other (palatable) mimetic butterflies in the brush-foot family. The males have a pair of concealed yellow brush-like hair pencils near the tip of the abdomen, which they are able to extend for mating purposes or as a deterrent to predators unaware of their toxic properties. These hair pencils can emit a characteristic musk-like odour. In the tropical north these butterflies aggregate in large numbers during the heat of the day in shady places.
Larval food-host: Numerous native and introduced milk-sap plants. Suitable native plants in S.A. are Carissa ovata (lanceolata) (conker berry) (Apocynaceae); Ficus brachypoda(platypoda) (native fig) (Moraceae); Cynanchum spp (native pears), Marsdenia(Leichhardtia) australis, Sarcostemma viminale australe (caustic bush) (Asclepiadaceae); and introduced plants *Asclepias curassavica, *Gomphocarpus(Asclepias) fruticosus, *G. physocarpus (balloon cotton-bush), *Hoya spp (wax plants) (Asclepiadaceae); *Mandevilla spp (Chilean jasmines), *Nerium oleander, *Trachelospermum spp (star jasmines) (Apocynaceae). The larvae normally eat the leaf and soft stem parts.
Eggs: Egg pits are hexagonal shaped.
Flight period in S.A.: This butterfly is seen all year round in the tropical north of Australia. During seasons with abnormal humidity it will move south during summer and autumn, occasionally reaching South Australia and Victoria where sightings have occurred from January to April.
Distribution: Normally a tropical and subtropical butterfly with vagrant tendencies. Interestingly, it was one of the first butterflies to be recorded from South Australia, with a specimen collected in 1864. Most of the South Australian records were during the abnormal summer humidity of the 1973-1974 season. In February 1974, a small breeding colony was reported in suburban Adelaide on Mandevilla (Chilean Jasmine), with adults flying in mid-March. This colony was short lived. It is doubtful if the butterfly is biologically suited to Adelaide conditions, and the butterfly has not established itself in Victoria. Other subspecies occur through Southeast Asia to India.
Habitat: Its native hostplants occur in the far-north of the state and it is possible that opportunistic breeding of the butterfly may occur in that area.
Conservation Status in S.A.: A vagrant. Very common in the tropical north of Australia.
Threats: No major threats.
Conservation Strategy: None required.
Author: R. GRUND, © copyright 6 September 2000, all rights
Last update 20 January 2002.