Tracing Black Cutworm and Armyworm (Lepidoptera: Noctuidae) Northward Migration Using Pithecellobium and Calliandra Pollen

Identifying the pollen attached to black cutworm, Agrotis ipsilon (Hufnagel), and armyworm, Pseudaletia unipuncta (Haworth), moths provided a powerful tool for recognizing food plants used by these noctuids before initiation of long-range movement. Pollen was found primarily on the proboscis and in decreasing frequency on the eyes, legs, and antennae. Fourteen moths collected in Iowa and Missouri were marked with the exotic pollens Pithecellobium spp. or Calliandra spp, or both. These plants are indigenous to southern climes, and the closest site of origin to the capture points is in southern Texas. From the closest plant location in Texas, these moths traveled 1,300km to central Missouri, 1,450 km to northern Missouri, and 1,600 km to central Iowa. Moths captured in March probably originated ≥600 km farther to the south than those captured in late April and May. Known exotic pollen was discovered on moths captured during May in Iowa, but these same pollens were found on moths captured earlier in Missouri. These results provided evidence of moth immigration into Missouri from within Mexico, possibly from the state of Tamaulipas.