Geographic range, impact, and parasitism of lepidopteran species associated with the invasive weed Lantana camara in South Africa

Abstract

The current status of species of Lepidoptera associated with Lantana camara L. (lantana; Verbenaceae) in South Africa was reviewed following a survey aimed at confirming their identity, geographic range, impact on the weed, and parasitism. Six species of Lepidoptera are established on lantana of which two are native, two were probably inadvertently introduced, one was deliberately introduced, and the status of one is unknown. Hypena laceratalis Walker and Characoma submediana Wiltshire (both Noctuidae) are indigenous to South Africa and have extended their host range from native plants to include lantana. Epinotia lantana (Busck) (Tortricidae) and Lantanophaga pusillidactyla (Walker) (Pterophoridae) are exotic species that are presumed to have been inadvertently introduced with the weed. Although three species were deliberately introduced as biological control agents, only Salbia haemorrhoidalis Guenée (Pyralidae) was successfully established. The origin of the serpentine leaf-miner, Aristaea onychota (Meyrick) (Gracillariidae) is still unclear. The moths have mostly established throughout the geographic range of L. camara in South Africa, although S. haemorrhoidalis is restricted to the moist eastern inland and coastal regions. Field populations of all six Lepidoptera species usually occurred at low densities over their established range, but occasionally increased to high densities in localized areas. As a result, the overall impact of these species was usually minimal, and only S. haemorrhoidalis and H. laceratalis were considered to significantly reduce the growth and reproductive rates of lantana. The recovery of several hymenopteran and dipteran parasitoid species from the Lepidoptera species surveyed suggests that a high incidence of parasitism may be the major factor limiting population increases of most of the moth species. This study supports the contention that additional agents are required to supplement the biological control of L. camara in South Africa.