Monarch Rearing Instructions (Source:

  • Eggs should be kept in a container lined with a moist paper towel to keep the milkweed from drying out.
  • The eggs should hatch within 1-5 days if kept at normal room temperatures. On average 70-90% of eggs hatch and survive to adulthood. Those that are infertile, or have genetic abnormalities, do not hatch.
  • After hatching, the larva will eat its chorion (eggshell). It may also eat other, un-hatched, eggs if they are nearby.
  • Larvae (caterpillars) can be kept in an aquarium, large jar, ice cream bucket, bug cage, or another relatively large cage. The container should be easy to open, since you need to clean it every day, have a screen covering or holes for air flow, and allow you to see the larva inside. It should be large enough for the adult to expand its wings when it emerges.
  • If you have used your cage for monarchs before, wash it well before you use it again. If at all possible, you should sterilize it with a weak (5%) bleach solution.