butterflies only migrate during the day. At night, they come down to rest.
They spend the night in trees, clustered together in “roosts”
In the morning,
the butterflies must warm up before they can fly. To fly WELL they need
to attain thoracic temperatures at least 55 F (13 C). (Monarchs cannot
even crawl when their thoracic temperatures are below 41 F (5C).)
shows, temperatures drop as the fall season progresses.
have a shorter and shorter window of time each day in which they
is one reason monarchs must leave the north before it gets too cold!
how the temperatures fall in the fall!
This! Too Cold to Fly Today?
and graph the daily temperatures in your
hometown this fall. When does the temperature drop below 55F?
- As the
season continues, for how many hours in each 24 hour day is the temperature
that monarchs can bask in the sun and/or shiver to raise their temperatures
above air temperature. Therefore, keep track of sunny and cloudy days
to get a better sense of when monarchs could fly.
Science Education Standards
changes from day to day and over the seasons.
- The behavior
of individual organisms is influenced by internal cues (such as hunger)
and by external cues (such as a change in the environment).
of an organism's internal environment involves sensing the internal
environment and changing physiological activities to keep conditions
within range required to survive.