It's a velvety green caterpillar. It's a tough brown pupa. It's a large, mottled gray moth.

Manduca sexta, or the tobacco hornworm, is all of the above, which is one reason (or three reasons) why the popular biology-lab animal has become a pet and living science lesson in the primary grade classrooms of Tucson, Arizona. The Manduca Project, run by the University of Arizona's department of biochemistry and molecular biophysics with a grant from hhmi, helps teachers exploit the 40-day life cycle of the hornworm to capture the attention of first, second and third graders.

Although the young Manduca breeders don't realize it, they're also honing their powers of observation and expanding their knowledge of biological systems, diversity, metamorphosis and the relationship between structure and function—all elements of Arizona's state science education standards. The project also addresses math standards as the children measure and graph the growth of their hornworms. Some classes have composed songs and poems about their multilegged pets.

More than 3,500 first, second and third graders so far have raised tobacco hornworms from egg to moth. University of Arizona undergraduates, who work with the teachers and children to study these insects, take what they learn back to their own labs for further exploration. Kim Keene, for example, did her senior research project on a digestive enzyme that helps Manduca sexta move through its many molts and rapid growth.

For more information www.manducaproject.com

—Jennifer Boeth Donovan

Photo: Courtesy of The Manduca Project/University of Arizona

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Reprinted from the HHMI Bulletin,
September 2002, pages 28-32.
©2002 Howard Hughes Medical Institute