Challenge Question #6: A Warm September!

Temperatures were unusually warm in the month of September. How might these temperatures affect the migration?

Question: In what ways could a monarch benefit from warm temperatures. What risks can you imagine?

Answer: Thanks to Mrs. Schnorr's and Ms. Oldham's classes, both in Minnesota, along with homeschool students Billy and Eric for providing these ideas:

Possible benefits of a warmer fall:

• We think the warmer temperatures will give the monarchs more time for their migration to Mexico.
• We also think the flowers will last longer so the monarchs can find nectar.
• More eggs could develop, so more butterflies.

Possible risks of a warmer fall:

• Could get caught in cold unexpectedly,
• They might stay too long and die when the temperatures get cold.
• When the weather gets colder it will change more quickly than the usual slow change of the tempatures. Even I think it would be hard to go from summer weather to the middle of fall weather.
• Another risk is their enemies could benefit from the warmer temperatures.
• Heat too high could be too dry for butterflies, drought could mean not enough water, and shriveled flowers so not enough nectar.

Possible benefits:

• A longer migration season: Monarchs need warm temperatures to fly (above 60F when cloudy or 50F when sunny).
  • The butterflies could have more days to fly.
  • The butterflies could have more hours each day to fly.

   

• A longer growing season:
  • More time for monarchs to develop: "Late" monarch eggs, larvae and/or chrysalids have time to develop. This could results in a larger monarch population. An extra generation of monarchs could have time to develop in some places. The danger of frost is also avoided.
  • More time for plants to grow: If not killed back by frost:
    • some flowers could continue to flower and produce nectar.
    • milkweed could be available in some places.

Possible risks:

• Too cold to fly
  • If warm temperatures cause monarchs to delay their migration they may get trapped by cold before they escape the north; abnormally warm temperatures chould change quickly when they do go back to normal.
• Not enough nectar
  • Frozen flowers!
  • Not enough flowers. Flowers do not bloom forever. Nectar is only available while the flower is blooming. Warm temperatures could cause some flowers to go through their blooming cycle more quickly. Nectar might not be available when the monarchs need it.
  • Not enough to eat. Monarchs burn more energy in warm temperatures. Their metabolism is faster. Fall is the time they need to store energy for winter; they might be burning more than they should.
  • Milkweed can get old ("senesce") more quickly in warm temperatures.
• Wind and migration: There can be more south winds when temperatures are warm. This could make migration more difficult.

Unknown

• Enemies: Predators and disease populations could be affected.
• Water: Rain and dew could change and monarchs might not get the water they need.
• A system out of tune: There are countless factors we don't know about that could be out of synchronization. Monarchs depend on resources that are only available periodically so coordinated timing is important, especially during migration.