Monarch Butterfly Biology, Ecology, and Conservation Needs

On Tuesday, December 9th, SSILL welcomed Kelsey E. Fisher, Ph.D. from Connecticut’s Department of Entomology. Kelsey presented the amazing life cycle and migration of the Monarch Butterfly.

The monarch butterfly overwinters in the mountain forests of central Mexico before beginning its remarkable northward migration to North America each spring and summer. This journey is completed over multiple generations. As monarchs move north, they lay eggs on milkweed plants; those eggs hatch into caterpillars, form chrysalises, and emerge as adult butterflies that continue the migration. Each successive generation carries the species farther north, repeating the life cycle along the way.

Monarch populations have been declining in recent decades, largely due to the loss of milkweed—the only plant on which monarchs lay their eggs and the sole food source for monarch caterpillars. As agricultural practices, development, and landscaping changes reduce milkweed availability along migration routes, monarch survival is increasingly threatened. In Connecticut, monarchs typically arrive in July, relying on healthy stands of milkweed to reproduce successfully.

Kelsey has studied milkweed growth extensively and explored practical strategies to support monarch populations. Her research includes effective planting and maintenance techniques, such as cutting back milkweed when it becomes overly mature to encourage fresh growth, as well as thoughtfully spacing plants to maximize their usefulness for egg-laying and caterpillar development. These approaches offer valuable, hands-on ways for gardeners and communities to help sustain monarch butterflies along their migratory path.

To learn more about the work that Kelsey does with the Monarchs and other insects, visit CT.GOV or The Connecticut Agricultural Experiment Station (CAES).