Monarch butterflies (Danaus plexippus), shown in caterpillar form above, are experiencing dramatic declines in population numbers. One method to help conserve species in decline is to rear and release captive individuals into the wild. Of course, this plan of action only works if captive-reared individuals are as capable as their wild counterparts. In a study published earlier this month, a team of researchers demonstrated that captive butterflies were less capable of migration than wild caught butterflies based on four key metrics. This result held for monarchs raised in either of two different rearing methods. Unfortunately, in combination with previous results from other studies, the authors suggest that captive rearing appears to be a conservation method that should be avoided for this particular species.
Sketch contributed by Megan McElligott (@MeganM_McE on twitter). Fact contributed by Adrian Perez.
Source: Davis, A.K., Smith, F.M. and Ballew, A.M., 2020. A poor substitute for the real thing: captive-reared monarch butterflies are weaker, paler and have less elongated wings than wild migrants. Biology Letters, 16(4), p.20190922.