Monarch butterflies are a key pollinator and complete an arduous migration as part of their life cycle. about their rapidly declining numbers, as the butterflies battle against climate change and pesticides. To tackle this, people are breeding them in captivity, and releasing them when they are fully grown.
To the untrained eye, captive butterflies are just as beautiful as wild ones. Scientists know that their aren’t as fine tuned as their wild counterparts – a process which is essential for the butterflies to successfully lay their eggs. To understand why, put some captive raised butterflies through their paces, to see if their beauty and brawn's lives up to that of their wild cousins.
Both captive and wild butterflies performed a grip test. By measuring the force needed for the butterflies to release their grip on a branch, researchers discovered that the captive butterflies strength was not up to wild standard. Captive butterflies also have much paler and shorter wings than wild butterflies.
These three traits are essential for successful migration. Grip strength, in particular, is what the butterflies need to latch onto branches and trees when resting or if winds become too severe.
In captivity, there is no “survival of the fittest.” The butterflies are reared and nurtured, and most of them survive. If these captive butterflies mate with the wild population, their offspring might be at a big disadvantage. Beyond that, the authors of the paper note that their findings explain a trend of decreased migratory success in captive-reared monarch butterflies.