Received for publication 22 July 1985. Journal Series No. 2966 of the Hawaii Institute of Tropical Agriculture and Human Resources. This work was partly supported by National Science Foundation Grants PCM-7909808 and DAR-791226. We wish to thank Sharon Barta and Mark Weisensel for technical assistance on this project. The cooperation of the staff of the Univ. of Wisconsin Biotron is also gratefully acknowledged. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper therefore must be hereby marked advertisement solely to indicate this fact.