Monarch migration mystery – solved! (We think.)

BBC reports on the computer model that seems to explain how the monarch butterflies make their amazing Canada-to-Mexico trek:

Lead researcher Prof Eli Shlizerman, from the University of Washington, explained that, as a mathematician, he wants to know how neurobiological systems are wired and what rules we can learn from them.

“Monarch butterflies [complete their journey] in such an optimal, predetermined way,” he told BBC News.

“They end up in a particular location in Central Mexico after two months of flight, saving energy and only using a few cues.”

Prof Shlizerman worked with biologist colleagues, including Steven Reppert at the University of Massachusetts, to record directly from neurons in the butterflies’ antennae and eyes.

“We identified that the input cues depend entirely on the Sun,” explained Prof Shlizerman.

“One is the horizontal position of the Sun and the other is keeping the time of day.
“This gives [the insects] an internal Sun compass for travelling southerly throughout the day.”

Having worked out the inputs for this internal compass, Prof Shlizerman then created a model system to simulate it.