The beautiful noctuid moth Chasmina pulchra (Doubleday) (Lepidoptera: Noctuidae) is a highly dispersive species, now established on urban kurrajongs Brachychiton populneus in southern Australia

Abstract

ABSTRACT We report the establishment of the beautiful noctuid moth Chasmina pulchra in southern Australia following repeated self-introduction. First recorded in 1955 as a vagrant in suburban Adelaide, specimens have been collected or observed at an increasing rate since then. We have recently located a breeding population on the Adelaide Plains where the larvae feed on the introduced kurrajong tree Brachychiton populneus (Malvaceae), although other Brachychiton species are likely to be exploited elsewhere in its range. Native to the drier parts of eastern Australia, this drought-tolerant tree has been widely grown as a specimen or amenity tree in suburban Adelaide since the mid-nineteenth century. Chasmina pulchra appears to have an annual life cycle in South Australia, with adult moths active in the summer, December – March. Larvae cause characteristic scalloping on the leaf margins of the food plant. We present evidence that this tropical to subtropical native species has expanded its range into the southern half of the continent in the last few decades. We also report the first specimen collected in northern Tasmania, associated with a weather system that could have facilitated its movement across Bass Strait. Southward incursions are associated with both wetter and drier than average monthly rainfall totals just prior to the event. Together with recent records from southwestern Australia well beyond the natural range of a putative food plant, we conclude that C. pulchra is a highly dispersive species, behaviour consistent with at least one other species of Chasmina in the Old World.