I've been asked if releasing captive-raised butterflies harms the wild population. I believe the answer is "no," based on how our program raises monarchs.
Concerns raised by conservationists about raising monarchs in captivity...
- Captive breeding is known to reduce the genetic health of monarchs.
- "Rear no more than ten monarchs per year (whether by a single individual or family)."
- Collect monarchs locally and release locally with sufficient time to migrate.
- Diligently work to minimize disease transmission.
- Participate in citizen science programs or conservation projects.
- Captive-raised adults might not be able to find their direction during migration.
I'll discuss each of these concerns below:
1. Large-scale, prolonged commercial breeding operations can cause inbreeding and loss of genetic fitness by "domestication." Since we capture our breeders in the wild and raise monarchs only for one generation, neither of these problems can arise. In the years when we have kept monarchs in captivity for several generations over one summer, we crossed two separate breeding lines to prevent inbreeding. Never purchase monarchs from commercial breeders.
2. At the most, each class rears 10 caterpillars. In the future, we may reduce it to 5.
3. We source and release all monarchs locally.
4. Feedback from teachers indicate they see little disease. A few teachers see high mortality, but in most cases, it's likely caused by factors other than disease--wandering caterpillars or dehydration. We screen our egg-laying females for the OE parasite using a microscope. We recommend washing milkweed food with a bleach solution (then tap water) to sterilize it. We sterilize containers. We depart from recommendations of butterfly scientists in that we raise more than 1 caterpillar per container, in large bins with several monarchs per upright stem of milkweed. We believe this method is acceptable because it requires less labor, closely mimics nature and, in our experience, results in little disease. Report any cases of disease (not caterpillar disappearance) you see to me.
5. It's essential that teachers introduce conservation to their monarch lessons, for two reasons. The first is to "directly benefit monarchs" as a way of mitigating any possible harm from taking them into captivity. The second is to foster a sense of optimism, or "can do" among children. If you mention that they are endangered, but do nothing to help monarchs, then you are teaching passivity. There are many citizen science programs you can participate in--such as tagging your butterflies before you release them. It's easy and fun to take the seeds from pods to grow milkweed.
6. The concern about direction finding during migration is based on a hunch. Monarchs probably find the right direction using a sun compass, which depends on an internal clock. Monarchs raised indoors might not have an accurate internal clock, according to this reasoning. Research addressing this has not proved its case. If you remained concerned about this, you can raise your caterpillars on a windowsill where they are exposed to daylight.