A study published earlier today, on Monday, June 24, 2019, in the academic journal Proceedings of the National Academy of Science found that monarch butterflies that are born in captivity are born without the instinct to migrate.
The monarch butterfly, which is important to many ecological processes in North America, has been experiencing population decreases for a few decades now. Countless ecological concerns across Canada, the United States, and Mexico have tried to beef up the population of monarch butterflies and otherwise increase their chances of experiencing population growth. Unfortunately for these conservational concerns, the aforementioned study, which is titled “Migration of butterflies bred in captivity,” monarch butterfly breeders’ efforts will have to be modified if they hope to bring “normal” monarch butterflies back into widely populating North America.
Researchers found multiple reasons behind why monarch butterflies raised in captivity don’t migrate south during winter and north as higher latitudes’ weather warms back up. One of the most prevalent reasons why monarch butterflies brought up outside of their natural environments is that they are born without the genes that encourage migration. Another major reason why monarchs don’t migrate if born in captivity is that they are not exposed to the environmental cues that spur monarch butterflies to migrate.
One potential flaw in the recent research that has been pointed out is that only one major commercial breeder’s butterflies were tested.
If the characteristic not to migrate is commonly developed among monarch butterflies that are bred in captivity, whether by local-level breeders or their commercial counterparts, breeders are effectively setting the species back by, according to academic researcher Karen Oberhauser, part of the arboretum college at University of Wisconsin-Madison who was not a part of the Proceedings of the National Academy of Science study.
It doesn’t help that the captive-bred monarchs, on average, produced more eggs per breeding cycle than compared to their better-off, natural-bred cousins.
According to the United States Fish and Wildlife Services, the collective population of monarch butterflies across North America – the most-populated, mid-ground portion of North America for the endangered species – has dropped upward of 80 percent since 1999, making them a long-term, up-front stay on the continental roster of endangered species.
Breeders have a market for selling monarch butterflies, as common enthusiasts of them know that they are helping brighten their future in North America by releasing them collectively when monarchs are heading south to Mexico based on their latitude of location. People often keep them as pets for months, if not longer, before letting them go.