Monarchs and Melon Preference_1_

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					                        Monarchs and Melon Preference


                                       Michele Koomen

                                Fall 2007- November 15, 2007

                              Roxi Brace (
                            Chelsey Cook (
                           Lindsey Radloff (
                            Sara Scholin (

“On my honor, I pledge that I have not given, received, or tolerated others’ use of unauthorized

                                 aid in completing this work.”
       Our experiment was to determine whether or not monarch butterflies have a preference
between cantaloupe melon or honeydew melon. In order to find this, we had three cages, each
with three monarchs. In those cages, we placed two dishes of cantaloupe and two dishes of
honeydew. We ran our experiment for five days and on the third and fifth day we changed the
layout of where the two kids of melon were placed. We then observed the butterflies for
approximately 15 minutes at 10:00, 1:00, and 4:00. We recorded our results of whether they
nectared or not. At the end of the five days we compared the number of honeydew marks to the
number of cantaloupe marks. From this, we found out that of the 46 times we observed a
monarch nectaring, 33 of the times it was on cantaloupe melon and 13 times it was on honeydew
melon. We are uncertain as to whether monarchs have a preference in melon choice, whether
monarchs can survive off just melon, and whether the temperature, light, time of day, humidity,
and disruptions has an affect on monarch eating habits. Two new things that we learned are
having only one piece of fruit in each dish versus four pieces makes a difference and how Do
monarchs have a preference between cantaloupe and honeydew melons?

       While reading and discussing Last Child in the Woods by Richard Louv, many of us
began thinking about our childhood and the various different activities we took part in as
children. One of the team members had three or four large lilac bushes in their backyard and
remembered them always being full of butterflies during the spring and summer months. After
learning about monarch butterflies so extensively and raising our own, our group was interested
in researching and testing eating habits of the butterflies since many of us had great childhood
experiences with monarch butterflies. Included in our course packet was information on
monarchs and their eating patterns. We took note that one page said monarchs would feed off of
anything in a liquid form, including pieces of melon, like watermelon, cantaloupe, and honeydew
melon. This information was found at Monarch Watch, an educational website about monarchs
created by the Kansas Biological Survey at the University of Kansas, giving the step by step
process of rearing a monarch and how to care for this organism in its various stages. We also
found some interesting facts from Enchanted Learning, an online picture dictionary for children,
with information about the monarch butterfly. After coming up with various ideas on

experiments we could complete with monarch butterflies, our group was most taken with the
idea of testing melon preference, since melon was something monarchs ate, but we didn’t know
much about. We decided to test if monarch butterflies had a preference of melon, using
cantaloupe, honeydew, and watermelon. When coming up with ways to supply the melons, our
best bet was to get melon everyday from the Gustavus Cafeteria. However, watermelon was
going out of season as we began our experiment, making it too difficult to test. We decided to
test just cantaloupe and honeydew melon and we wondered, do monarch butterflies have a
preference between cantaloupe and honeydew melon? As a side note on our experiment, we also
placed the melon in various areas throughout the experiment to make sure that placement of
melon was not an unexpected variable. We had three different hypotheses for this experiment:

HA0: The monarch butterflies will have a preference to cantaloupe melon over honeydew melon.
HA1: The monarch butterflies will have a preference to honeydew melon over cantaloupe melon.
HA2: The monarch butterflies will have no preference to either cantaloupe melon or honey dew
     melon, but will simply nectar randomly.

Design and methodology
       For our experiment, we chose to use nine butterflies in three different cages. By splitting
the butterflies up, it would be easier to tell which butterflies were nectaring and which weren’t
and there wouldn’t be the worry of whether or not there is enough food. We placed all three
cages in approximately the same location so they would receive the same amount of sunlight.
Part way through our experiment, we condensed down to two cages when two of our monarchs
died. We placed a thermometer in the middle of the two cages so we could record the
temperature. We also made sure that we observed the butterflies at the same time each day
(10:00, 1:00, and 4:00) so that freshness of fruit and daylight wouldn’t become extraneous
variables. We had a standardized recording sheet so that each member of our group recorded
their data in the same way. Each member of our group took turns observing the monarchs for
approximately fifteen minutes a sitting. The butterflies were all kept in Mattson Hall so that
everyone would have the same access to the experiment and temperature could be monitored.
We placed approximately the same amount of fruit in each Petri dish and placed them in the
same locations each time they were removed, varying the location of each melon time after two

days. We varied the placement to make sure placement of melon was not a determining factor in
how melon preference. At the start of our experiment, we only placed one piece of melon (of
equal proportions) in each dish. After two days, and the death of two of our test subjects, we
increased the amount of melon from one piece to four pieces, again, still of equal proportion. We
increased the amount of melon to insure that there was enough liquid content for the rest of the
monarchs to survive and to make sure that the monarchs could see the fruit left for them. Our
entire materials list for this experiment includes: nine monarch butterflies, three butterfly cages,
twelve Petri dishes, 60 pieces of fruit (30 cantaloupe and 30 honeydew), a scale for massing out
the monarchs, nine envelopes used to hold the monarchs during massing, and 45 data collection

          For data tables, please view Appendix A. Total; the nine monarchs visited the melons 46
observable times. 33 of those times were visits to cantaloupe and 13 of those visits were to
honeydew. In order to calculate the mean number of visits a butterfly made to each type of
melon, we used only the results from Cage one and Cage two as we did not have equivalent
information collected from Cage three. The mean number of visits one of the seven monarchs
made to cantaloupe melon was 4.29 visits. The mean number of visits one of the seven monarchs
made to the honeydew melon was 1.57 visits.

Interpretation and Discussion
          After performing the chi-squared test, we accepted Ha1: Monarchs prefer cantaloupe
melon over honeydew melon because the calculated x2 value was greater than the critical x2
value. For the steps in finding this number, please see Appendix B.
          After reviewing these statistics, we can suggest with a 99% accuracy that monarchs do
have a preference of cantaloupe melon over honeydew melon. The original question was whether
monarchs had a preference of melon types. At the beginning, the belief was that there wouldn’t
be a statistically significant advantage of one melon type over the other type because both pieces
were the same size, contained natural sugars and water for hydration, and were from the same
family, Cucurbitaceae. There are many variables that could affect this experiment, however

some of the major ones are, the amount of test subjects, the length of the experiment, and the
availability/freshness of the melons. In order to make a stronger inference, we would have to
repeat this experiment many times over. This was only one trial. It is completely possible that if
we ran the experiment again, we would find opposite results.
       When considering what we have learned from completing this experiment, we feel that
some of the major concepts are how it is difficult for a scientist when conducting an experiment
to predict every problem or variable that may arise, how to handle and care for monarchs, how to
set up, run, and analyze an experiment, and how to work as a group. All of these concepts are
ones that are applied in elementary school science classes and in daily life. By discovering and
thinking about these concepts now, we will be better prepared in our future classrooms and this
will in turn better our students as we will be more prepared and knowledgeable about science.
Many elementary schools raise monarchs as a class science project and by having raised our
own, we are much more capable and understanding of the work involved in caring for these

Implications and for future work
       There are many things in an experiment that cannot be seen or known until it is already
underway. Each experiment varies with the number and amount of these implications, but there
are no doubt things that are learned to help with ideas for future experiments and ways of
shaping future research and experiments in certain categories. We learned many things from this
one experiment that would make the next one a better success. It would be necessary to have
numerous test subjects, instead of using a small number like eight or nine. This is a fair number,
but more monarchs would have equaled a better and more accurate outcome of the experiment. It
would also be important to have a good amount of melon located in the butterfly cages. We
started with one piece of melon in a Petri dish, but noticed our butterflies were looking weak and
unhealthy. By placing four pieces in a dish made it easier for the monarchs to see and therefore,
made it more accessible for them to nectar. Monarchs are very fragile organisms, so taking care
of them is an important part of the experiment. It may have been helpful to monitor them more
than three times a day and for a longer period of time. Light affects the feeding cycle of
monarchs, so making sure to check them during daylight hours is a crucial part to the
experiment. Another thing may be to keep them in a place of isolation, where they cannot be

disturbed by the many people going in and out of Mattson 101. Some of the other experiments
happening at the same time required the lights to remain on all of the time. As light affects
monarchs, this may have affected the outcome of our experiment since they never fully
experienced a “night” during the time of monitoring them.
       Since it is already known that monarch’s nectar from different types of melons, it may be
interesting to test between various liquids to see if the monarchs have any preference between
different liquids instead of using two types of melon. The experiment should also run for a
longer period of time and with many different types of food.

Limitations of your experiment
       Due to limitations of this experiment, we can only suggest possible answers to the
presented experiment question of whether or not monarchs have a melon preference between
cantaloupe and honeydew when eating. The number of monarchs limited the amount of data that
was able to be collected. We only had access to nine monarchs, which two of them died leaving
us with a total of seven. A larger sample size would allow us to make a stronger implication to
the eating preferences of the entire monarch community. We had a tiny representation of the
monarch species and for only a short period of time, in which we were able to observe and test.
The length in which we were able to run this experiment also presented a restriction of how well
we could make an inference from the results. We had the monarchs for only a partial amount of
their lifecycle, which did not allow for a strong conclusion.
       Another limitation that was presented throughout the experiment was the temperature and
humidity of the environment the monarchs were placed in. We were not able to control this
factor, which possibly may have led to the death of some of the monarchs. A monarch’s eating
habit can depend on the temperature and dryness of the air. We are unsure as to whether the high
heat and low humidity of the air caused the monarchs to nectar more or less on the melons.
       The change in light was also a limitation that may have affected the results of the
experiment. The monarchs did not have a continuous pattern of light and darkness as would be
presented in their natural environment. There was continual change in whether the lights were on
or off and for how long.
       We also wanted to test more than two variables of melon in order to get a more accurate
result of melon preference and the melon we would have liked to add was watermelon. As we

were getting our melon supply from the Cafeteria and watermelon was quickly going out of
season, we decided that testing just two types of melon would be better for this particular
experiment because we could guarantee the availability of cantaloupe and honeydew, whereas
we could not guarantee the availability of watermelon. Having another variable in each of the
cages would have changed the data outcome in someway, but we cannot know if this would be a
major or minor change.

Appendix A: Results

                                       Butterfly Weight at Start and at Finish
                                         Weight at Start Weight at End
                         Butterfly One                   0.3 g                           0.3g
                         Butterfly Two                   0.4 g                           0.4g
                         Butterfly Three                 0.3 g                           0.2g
                         Butterfly Four                  0.4 g                           0.3g
                         Butterfly Five                  0.4 g                           0.4g
                         Butterfly Six                   0.4 g                           0.4g
                         Butterfly Seven                 0.4 g                           0.5g
                         Butterfly Eight                0.2g                             Dead
                         Butterfly Nine                 0.3 g                            Dead

                         Mean Weight                             0.34g                   0.36g

                                   Number of Visits to Melon by Monarchs

                                                      Cage One
                  11/7                 11/8               11/9          11/10            11/11          Total
              C          H         C          H       C       H        C     H       C           H     C      H
 10:00    0          1         0          0       2          0       1      0    2          1        5      2
  1:00    2          0         0          0       1          0       0      0    2          1        5      1
  4:00    1          1         0          0       2          1       2      0    1          1        6      3
 Total    3          2         0          0       5          1       3      0    5          3        16     6

                                                      Cage Two
                  11/7                 11/8               11/9          11/10            11/11          Total
              C          H         C          H       C       H        C     H       C           H     C      H
 10:00    0          0         1          0       1          0       1      1    4          1        7      2
  1:00    0          0         0          0       1          0       1      0    1          1        3      1
  4:00    0          0         1          0       0          0       2      1    1          1        4      2
 Total    0          0         2          0       2          0       4      2    6          3        14     5

                                                      Cage Three
                  11/7                 11/8               11/9     11/10          11/11                 Total
              C          H         C          H    C       H     C       H      C       H              C      H
 10:00    1          1         0          0       No data collected from Cage 3. On 11/8,            1     1
  1:00    2          0         0          0       two of the butterflies in Cage 3 died, so          2     0
  4:00    0          1         0          0       we moved the one left in Cage 3 to Cage            0     1
 Total    3          2         0          0        1 for the remainder of the experiment.            3     2

Mean number of visits to cantaloupe per butterfly: 30/7= 4.29 visits
Mean number of visits to honeydew per butterfly: 11/7= 1.57 visits
Median of both cantaloupe and honey dew overall: 1
Mode: 0 visits

Appendix B: Chi-squared Test

Question: Do monarchs prefer cantaloupe melon or honeydew melon?

H0: The monarch butterflies will have a preference to cantaloupe melon over honeydew melon.
HA1: The monarch butterflies will have a preference to honey dew melon over cantaloupe melon.
HA2: The monarch butterflies will have no preference to either cantaloupe melon or honeydew
     melon, but will simply nectar randomly.

                                      Observed Data
                                Number of visits to melon types:

     Cantaloupe Melon                  Honeydew Melon                  Total # of Visits
            33                               13                               46

                                        Expected Data

      Cantaloupe Melon                 Honeydew Melon                    Total # of Visits
              23                               23                               46

                                       x2 = ∑ [(O-E)2 / E]

                   x2 = [(33-23)2 / 23] + [(13-23)2 / 23] = 4.35 + 4.35 = 8.7

                                            df= c-1

                                           df= 2-1=1

                                  Calculated value of x2 = 8.7
                                   Degrees of freedom = 1

                                     Critical Values of x2
 Degrees of Freedom              x 0.1                   x2 0.05                 x2 0.01
                           (90% confidence)       (95% confidence)          (99% confidence)
          1                    2.70554                  3.84146                 6.63490

8.7 >3.84146 therefore, we will reject the null hypothesis. We will accept Ha1: Monarchs prefer
cantaloupe melon. There is over a 99% confidence level meaning that it was not random.


        We would like to give a special thanks to Michele Koomen for all of her help throughout
this experiment, including the monarchs, the supplies to care for the monarchs, and the
information before and throughout the experiment in order to complete it.


Enchanted Learning. (2007). Monarch Butterflies. (Online). Available:

Monarch Watch. (2007). Rearing Monarchs. (Online). Available:


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Description: Melon can help make the body of excess fat, alcohol consumption factors play a role, but also has a diuretic effect, so that the body of excess water excreted with the urine.