6/24/2020

Rear them right

Photo credit to members Mark and Janna from Marion.
Monarch butterflies are back in Iowa and our members are HAPPY to return to their routine of finding eggs and raising caterpillars into mature monarch butterflies. Many members have also increased their plantings of milkweed and native pollinator plants and are happy to start seeing the blooms.

Now is a good time to review the "best practices" for raising monarchs to be healthy and strong.

(Copied from a previous post quoting Monarch Watch.)

The migration to Mexico is a strong selective force.
It eliminates the weak ... those with diseases ... the undersized ,,, and those with genetic and other deficiencies.

It also eliminates those that have not received the environmental cues that properly trigger diapause and the orientation and directional flight characteristics of the migration.

BEST PRACTICES

1. Rear larvae under the most natural conditions possible.
"In other words, rearing outdoors, on porches, in pole barns, open garages, etc., would likely produce better results than rearing in an air–conditioned kitchen, spare bedroom or similar space."

2. Provide an abundance of living or fresh–picked and sanitized foliage to larvae.  ..."raising the monarchs on living plants–potted or in the ground–is likely to produce the largest monarchs, provided that the monarch larvae have an abundance of foliage to feed on at all times. Cut foliage in the form of leaves also works well, but the leaves have to be fresh and abundant relative to the numbers of larvae in each container."

3. Provide clean rearing conditions.
 ... Containers should be cleaned each day once the larvae reach the 4th instar.
 ... Foliage should be sanitized.

"To avoid passing the monarch disease Ophryocystis elektroscirrha (O.e. or OE) from outdoor monarchs to reared monarchs, both the living and cut foliage can be sanitized using a 10% bleach solution with a drop or two of liquid soap added. After soaking in the bleach solution for two minutes, the leaves should be rinsed thoroughly with clean water and patted dry before being fed to larvae."

"Living plants can be sprayed with the bleach solution and then rinsed. If you are using cut stems with leaves intact, they can be cleaned the same way. In that case, be sure to cut the stems under warm water before placing them in vases, etc. The warm water keeps the latex vesicles from closing down the transport of water to the leaves. Cut stems work to feed larvae, but they can go limp and be less suitable as a food source than cut leaves."

4. Plan the rearing so that the newly–emerged monarchs can be tagged early in the migratory season (10 days before to 10 days after the expected date of arrival of the leading edge of the migration in your area. [MEI NOTE: The leading edge in Iowa is around September 8th, so that would mean tagging August 30 through September 18th.]

5. Tag the butterflies once the wings have hardened and release them the day after emergence if possible.

Also, read and learn about "Monarch Annual Cycle: Migrations and the number of generations", a blog post from Chip Taylor of Monarch Watch.