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This study shows that monarch butterflies need to grow up in the wild to develop their navigational abilities. Farmed monarchs from labs fly in random directions instead of migrating south as weather cools. So do wild monarchs raised by humans. Somehow, they're getting information from the environment that gets lost in captivity, even when humans make diligent efforts to recreate natural conditions.
On the downside, this means people shouldn't try to raise wild eggs or caterpillars for release. It doesn't increase the rate of successful migration.
On the upside, this tells us something vital and subtle about how migration and navigation work in monarchs. Followup studies may be able to determine what that instinct is, how and when it develops, what disrupts it, and so on. This could explain why the migration is failing so badly. It may not just be habitat loss -- if something is screwing up navigation, we need to know what so we can stop doing it.
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