The long-distance movement of the adult H. zea has intrigued entomologists for years. For example, Callahan et al. (1972) trapped H. zea in black light traps at levels up to 318 m. Glick (1965) netted H. zea from an airplane flying at 157 m. Sparks et al. (1981) captured H. zea on unmanned oil riggs 161 km. from shore.

These examples show H. zea is in the air but provide little information as to the origin or destination of the moths. Direct tracing of the moth has proved difficult. Results from mark, release and recapture studies are often poor, and massive numbers must be reared.

A Finnish worker, Mikkola (1971) has suggested the use of pollen for determining long-distance movement of several Lepidopteran spp. The results from his study were inconclusive since little variation in vegetation or blooming dates occurred between capture and possible origin sites. However, in the United States there is great variation between plant communities suggesting the possible use of pollen to trace H. zea movement.

Pollen has at least 4 advantages for movement studies. 1) Plants and insects have coevolved a system whereby pollen is transported on the insects, 2) the exine, or rigid exterior, of pollen is composed of sporopollenin, one of the most enduring of natural elements, 3) identification is based on exine structures and pollen may often be identified to genus, and 4) geographic distribution and flowering periods are fairly well known. Therefore, it is possible to determine geographic origin of moths which bear pollen.

In this study, adult male H. zea were captured using cone type pheromone traps baited with Zealure. Moths were killed by crushing the thorax and were placed individually into 21 ml. cups and frozen.