Monarch Butterflies Use Internal Sensors to Survive Winter

This 2017 photo shows monarch butterflies at Point Pelee National Park in Canada. A large population of already vulnerable monarch butterflies got stuck in Canada and in the Northeast because unusually warm weather delayed their flight. Winds and other factors made it next to impossible for them to go south before frost. (Darlene Burgess via AP)

(CN) – Scientists have found monarch butterflies are equipped with some remarkably sensitive and finely tuned internal temperature gauges that allow them to effectively navigate seasonal shifts – a task made much more complicated by the effects of climate change.

In a study published Wednesday in the academic journal Molecular Ecology, researchers report examining monarch butterflies in a controlled lab environment in which the butterflies were exposed to different temperature and climate conditions. By monitoring the behaviors of the butterflies under these scenarios, researchers determined monarch butterflies possess a timer-like biological mechanism that allow them sense when spring is approaching with stunning accuracy.

D. André Green, biologist at the University of Michigan and co-author of the study, and a team of researchers set out to better understand how monarch butterflies operate while overwintering, a process known as diapause. Undergoing diapause allows a butterfly to enter a dormant state to increase its chance of surviving winter climates, a process Green and his team wanted to better understand.

Researchers noted diapause, a hormonally charged action, is not negatively affected by low temperatures. For most living creatures, colder temperatures slow down hormonal response times, but in butterflies the cold allows diapause to be faster and more precise. Researchers also found a buildup of calcium within the heads of monarch butterflies play a crucial role in allowing the butterflies to gauge temperatures so effectively.

The researchers found that by examining just how this process works, further discoveries may show how butterflies experience such controlled migration events.

They conclude the butterfly’s capabilities could be a useful source of information as we continue to study and combat the effects of climate change on the creatures, whose populations at overwintering sites have sharply declined for decades. With butterflies so innately sensitive to minute temperature shifts, observing their behaviors and diapause activity in the wild could help researchers monitor the true extent of long-term climate change.

Green did not respond to a request for comment by press time.

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