A group of researchers may have just solved the secrets of the monarch butterfly’s migration. Scientists say that they have found the mechanism behind the majestic butterfly’s internal compass, which helps it find its way to central Mexico on its annual 2000-mile-long journey.
The journey still starts every fall even though the number of monarch butterflies dwindled over the years due to major losses of milkweed, which helps their larvae reach maturity.
University of Washington’s Eli Shlizerman, lead researcher involved in the new findings, explained that the tiny insects find their way southwest every year due to their internal compass. The bodily mechanism contains two pieces of information, Shlizerman said, i.e. the sun’s position in the sky and time of the day.
The butterfly needs this info to find its direction during its annual migratory trip. Past research had shown that the animal can gather info on the time of the day and sun location but no study had been able to crack the mystery around how that data was received and processed in the brain.
Yet, a joint team of researchers from the University of Washington, University of Massachusetts and University of Michigan believes it has cracked the mystery. Researchers used computer models to simulate the butterflies’ annual journey.
Shlizerman said the models helped his team find how exactly the animal used that information to keep a constant direction toward southwest each fall.
Study authors explained that monarchs use their eyes to gather info on sun’s position, but they also need notions about the time of the day to find direction. Scientists found that the small animals have an internal clock that can deliver that piece of information in their antennae. From there the piece of info reaches the brain where it gets processed.
Past studies had also focused on the biological rhythms in the animals’ antennae nerves that regulate their bodily clock. But the latest study recorded the signals coming from antennae to the brain and the patterns followed by sunlight through the monarchs’ complex eyes.
The data was inserted into a computer model that performed simulations on how the data reach the brain. Researchers planned to learn whether the two bits of info were enough to help the butterflies sustain navigation to the southwest.
The model revealed that the antennae are packed with a pair of control mechanisms, one inhibitory and one excitatory, that help the monarch butterfly ‘read’ the signals from the eyes to tell sun position and discern the direction to the southwest.
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