Evolutionary and taxonomic relationships between fruit-piercing moths and the Menispermaceae

Abstract

Twining vines of the family Menispermaceae provide the food for larvae of the principal fruit-piercing moths in Australia, and in most of the Old World tropics and near tropics. These large noctuid moths are adult pests of a range of commercial fruits, and can cause crop losses of more than 50%. In Australia, the Menispermaceae are represented by 13 genera and 24 species, which predominantly occur through coastal and subcoastal regions in the east and north of the continent. Their density and diversity is greatest in the wet tropical forest areas of north-east Queensland. Around 60% of the Australian menisperm species are now known to support fruit-piercing moth larvae to various extents. While moth species-menisperm associations range from species specific (i.e. monophagy) to genera generalist (i.e. polyphagy), polyphagy appears to contribute less to a moth's status as a pest than habitat diversity. Tinospora smilacina and Stephania japonica are the two most widely occurring Australian menisperms, with forms or varieties occupying habitats from wet tropical forest to semi-desert, and these species are particularly important to the fruit-piercing moth problem. Some moth species-host plant associations appear to be dynamic, as indicated by the dietary expansion of the moth Othreis fullonia in recent centuries onto Erythrina spp. (Fabaceae) in New Guinea and the Pacific. The perceived relationship between Erythrina spp. and the Menispermaceae is through the similar alkaloids they possess (i.e. the tetracyclic Erythrina-type), which are found particularly in certain species within the tribe Menispermeae. Variation in the alkaloids associated with certain menisperm genera may explain specific moth–host plant relationships, which in turn support alternative tribal associations for some menisperm taxa to those currently recognised.