Host plants, biology and distribution of Acraea terpsicore (Linnaeus, 1758) (Lepidoptera: Nymphalidae): a new butterfly for northern Australia with potential invasive status

Abstract

AbstractThe nymphalid butterfly Acraea terpsicore has recently become established in northern Australia where it is spreading rapidly. The immature stages are briefly described, illustrated and compared with those of A. andromacha (Fabricius, 1775) from Australia, and information on its larval food plant specificity, biology and distribution is presented. The species occurs in highly modified open areas, including suburban roadsides, disturbed grassland (i.e. cleared woodland that is regularly slashed or graded) and degraded savannah woodland where it breeds primarily on Hybanthus enneaspermus (L.) F.Muell. (Violaceae), a widespread native herb that is also used as a natural larval food plant in India, and to a lesser extent on Passiflora foetida L. (Passifloraceae), an introduced vine also used as a food plant in Indo‐China and Indonesia. Extensive laboratory larval feeding trials on Violaceae, Passifloraceae and Cucurbitaceae revealed limited ability of the Australian population to consume Passifloraceae and lack of ability to feed on Cucurbitaceae, indicating that A. terpsicore is unlikely to become a pest of vegetable and horticultural crops. It is hypothesised that the narrower host range in Australia is attributed to the founder effect of a limited gene pool. Within 14 months of colonisation, A. terpsicore has occupied much of the western half of the ‘Top End’ of the Northern Territory and spread to the eastern Kimberley of Western Australia, with an estimated extent of occurrence of 112 000 km2 and average dispersal rate of 315 ± 56 (SE) km/year. Because the butterfly has the ability to exploit (injure) Violaceae, and potentially outcompete A. andromacha, it may qualify as an invasive species.