Pollen as a marker for migration of Helicoverpa armigera and H. punctigera (Lepidoptera: Noctuidae) from western Queensland

Pollen carried on the probosces of Helicoverpa punctigera and H. armigera trapped in western Queensland and in cropping areas of eastern Australia in September 1989 and 1990 was identified by scanning electron microscopy. Ninety-five percent of moths carried pollen. A total of 19 'morphological pollen species', representing 14 plant families, was found. Up to 6 pollen species were found on individual moths, and 61 percent carried more than one. Pollen from plants unsuitable for larval survival was common. Pollen loads generally reflected the abundance of locally flowering plants, but there were exceptions which suggested migration. Pollen of Ptilotus (Amaranthaceae), Velleia (Goodeniaceae) and Eremophila (Myoporaceae), and the Asteraceae (Tubuliflorae) were found on moths trapped in the east. These plants either did not occur in the areas where the moths were caught, or did not flower there at the time the moths were caught. However, they were abundant in possible source areas such as western Queensland. Among moths caught in eastern regions, 30 percent of H. punctigera and 18 percent of H. armigera carried pollen from such plants. The value and limitations of moth-borne pollen as a marker for migration are discussed.