INTRODUCED PURPLE LOOSESTRIFE AS HOST OF NATIVE SATURNIIDAE (LEPIDOPTERA)

Purple loosestrife (Lythrum salicaria, Lythraceae) arrived in North Am erica nearly 200 years ago. In 1969 we first found larvae of the nativ e Cecropia (Hyalophora cecropia) and Polyphemus (Antheraea polyphemus) moths (Lepidoptera: Saturniidae) on loosestrife in the Hudson River V alley, New York, and we have since found Io (Automeris io) on this pla nt. A census of 4th and 5th instar saturniids in four 0.25 ha plots in purple loosestrife-gray dogwood (Cornus racemosa) wet meadows near Sa ugerties in 1984 indicated that Polyphemus and Cecropia larvae occurre d much more frequently on loosestrife than on dogwood, a native host. The switch from native woody hosts to an introduced herb may have been facilitated by the dense shrub-like habit, high productivity, and hig h tannin content of loosestrife.