How large-scale breeding affects insects’ fitness over the long term is not known, though studies in monarchs have shown that captive-bred individuals look different from wild butterflies, especially after a few generations, may not migrate as well, and have lower survival rates. This is a huge concern as classroom rearing kits have become more common and many people participate in the ever-more popular rearing and release of thousands of monarchs in the well-meaning hope of supplementing dwindling wild populations.