Why
is Nectar So Important to Monarch Butterflies
in the Fall?
Fall is the critical food-gathering time for monarchs for three important reasons--the three seasons of fall, winter and spring:
1) Fall: For their fall migration, said Mrs. Swentzel's and Mrs. Nunnally’s students in New Jersey and New Hampshire respectively.
2) Winter: For food and energy for the winter," added Mrs. West’s students in Texas.
3) Spring: And also to fuel the return migration the following spring!
Gaining Weight for Winters' Five-month Fast:
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This graph shows how much energy monarchs have, as stored fat, each month of the year. Notice how little is stored in the summer and how much this changes during the fall! At the overwintering sites in Mexico, very little nectar is eaten by the butterflies, if any. The overwintering period is like a 5-month weight-loss diet. Monarchs must survive all winter on the fat they accumulate during the fall. And, they must have enough energy left to fly back north in the spring.
Journaling Question
If you gained and lost as much fat (in pounds) as monarchs do (in milligrams) during the year, how much would you gain and lose each month? For fun, write a story about how this would affect your life."
So Busy Eating You Can Sneak Up and Grab One
Butterfly behavior changes noticeably in the fall as the importance of feeding increases, notes Dr. Lincoln Brower:
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| Listen to Dr. Brower . |
"If you try to catch a butterfly between your thumb and forefinger in the summertime you'll have a very, very hard time catching it. But they are so intently nectaring [during fall migration] that you can actually, if you're really careful, sneak up with your thumb and forefinger and just grab one. If they've had a good feed their stomachs will actually be fat. (See photo.) They feed on that [nectar], and the nectar has sugar in it. They convert that sugar into fat and that fat is the energy store that they use to fly down to Texas and then on into Mexico."
Monarch Morphology: The Proboscis
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National Science Education Standards
Life
Science
Organisms have basic needs. For example, animals need air, water and
food; plants require air, water, nutrients, and light. Organisms can
survive only in environments in which their needs can be met. (K-4)
Each plant or animal has different structures that serve different functions in growth, survival, reproduction. (K-4)
Living systems at all levels of organization demonstrate the complementary nature of structure and function. (5-8)
The behavior of individual organisms is influenced by internal cues (such as hunger) and by external cues (such as a change in the environment). (K-4)
Behavior is one kind of response an organism can make to an internal or environmental stimulus. (5-8)
National Math Standards
Numbers
and Operations
Compute fluently and make reasonable estimates.
Measurement
Understand measurable attributes of objects and the units, systems,
and processes of measurement.
Problem
Solving
Solve problems that arise in mathematics and in other contexts.
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