Natures wonders: migrating mpths use magnetic field (Introduction)

by David Turell , Friday, June 29, 2018, 14:20 (2339 days ago) @ David Turell

They fly at night so the field i s their only guide:

https://cosmosmagazine.com/geoscience/moth-species-uses-magnetism-to-migrate

"Monarch butterflies and bogong moths are the only insects known to undertake migratory journeys to specific sites year after year.

"An Australian species, bogong moths (Agrotis infusa) flee the harsh conditions of the arid plains by migrating long distances to spend summer in cool caves of the continent’s alpine region. The butterflies (Danaus plexippus) use an internal sun compass for their journey, but the bogongs moths can’t do that because they fly at night.

"How millions of the adult moths find their way across 1000 kilometres or more of country in darkness, then back again at the end of summer, was unknown – until now. New research published in the journal Current Biology reveals that, like migratory birds, they use the Earth’s magnetic field and visual landmarks to navigate this journey.

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"The team discovered that when a natural Earth-strength magnetic field and visual landmarks were presented together, the moths flew in a predictable flight direction. When the two were presented in conflict, they became disorientated after a few minutes.

"The findings led the researchers to conclude that bogong moths rely on a magnetic sense as well as sight. The researchers suspect that the magnetic sense is used to determine the general direction of flight, and then calibrated periodically with a visual feature such as the moon, particular stars or a mountain.

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"The ability of birds to sense the Earth’s magnetic field has long been established. Recent research suggests that the detection of magnetic fields is associated with sensory receptor molecules known as cryptochromes in the retina of a bird’s eye. This work is straying into new fields of quantum biology, but so far, no specific mechanism has been found."

Comment: More convergent evolution.The Earth's magnetic field plays a major role.