By: Anna Gillin
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How does caffeine effect the growth, survival,
and development of mealworms?
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Caffeine (C8H10N4O2) is a drug that stimulates
the nervous system
It gives consumers an increase in energy and
can elevate mood
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Caffeine is added to drinks and foods
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Side effects vary according to consumer
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Mealworms are the larva stage of the Darkling
Beatle
Mealworms are part of the Tenebrio Genus and
the T. molitor species
The larval stage of mealworms can last from
90 up to 114 days
As mealworms grow, they shed old shells and
develop new ones.
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The group of mealworms exposed to high
levels of caffeine will lose more mass and
have a higher death rate than the groups
exposed to lower levels of caffeine.
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500 milligrams caffeine
100 milligrams caffeine
135 mealworm larvae
Square plastic containers
Metal screens
Distilled Water
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Wheat Bran
Corn meal
Shredded Newspaper
Mortar and Pestle
Digital Balance
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The mealworms were divided into 3 groups:
◦ Group A (no caffeine)
◦ Group B (low caffeine)
◦ Group C (high caffeine)
15 mealworms were put into each box
The following solutions were made:
◦ Group A: 100 mL of distilled water
◦ Group B: 100 mgs ( ½ caffeine pill) in 100 mL of
distilled water
◦ Group C: 500 mgs (2 ½ caffeine pill) in 100 mL of
distilled water
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50 mL of the solutions were mixed with 50
grams of wheat bran and 50 grams of
cornmeal
The mass and survivors were measured
after a week and new bedding, solutions,
and food mixtures were made
The length of the experiment lasted 4
weeks
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Independent Variable- the amount of caffeine
given to each group of mealworms
Dependent Variable- the effects that caffeine had
on each group of mealworms and the number of
mealworms still living
Control- the group of mealworms (Group C) that
was not exposed to caffeine and only had food
moistened by water
Constants- the type of container, metal screen,
temperature, food, bedding in the container, and
amount of mealworms in each group
Mealworm Mortality Over 4 Weeks
25
Number of Deaths
20
15
10
5
0
Group A
Group B
Group C
Graph 1
Graph 2
Percent Change in Mealworm
Mass Over 4 Weeks
Percent Change in Mass
60
50
40
30
20
10
0
-10
-20
Group A
Group B
Group C
ttest of the Number Dead
0.034
ttest (Group A, Group B)
ttest (Group A, Group C)
0.035
ttest (Group B, Group C)
0.184
ttest of the Percent Change in Mass
0.306
Ttest (Group A, Group B)
Ttest (Group A, Group C)
0.088
Ttest (Group B, Group C)
0.708
ttest of the Percent Change in Mass/Organism
.530
Ttest (Group A, Group B)
Ttest (Group A, Group C)
.916
Ttest (Group A, Group C)
.297
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The hypothesis stated that the mealworms
exposed to higher levels of caffeine would
lose more mass and have a higher death rate
The hypothesis was partially supported
because caffeine had a negative effect on
mealworms
It was rejected that varying levels of caffeine
have different effects on mealworms
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The temperature should remain constant
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A different source of food should be used
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The environment should remain consistent
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Different organisms could be tested with
caffeine
The same experiment could be performed for
the mealworms in their adult form as beetles
A wider range of caffeine levels could be used
to see if different amounts of caffeine have
the same effects
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Mealworm Store. (n.d.). Mealworm Facts and Information. In Mealworm Facts and
Information. Retrieved 2007, from Mealworm Store website:
http://mealwormstore.com/mealworm_info.php
Smith Life Science. (2009, September 29). Mealworm Diagram. In Mealworms. Retrieved
October 5, 2010, from Smith Life Science website:
http://www.smithlifescience.com/MLMealworms.htm
University of Arizona. (1997). Darkling Beetle/ Mealworm Information . Retrieved
October 21, 2010, from Center for Insect Science Education Outreach website:
http://insected.arizona.edu/mealinfo.htm
Majithia, N. (2008). Caffeine: Understanding the World’s Most Popular Psycoactive Drug.
Retrieved October 7, 2010, from Journal of Young Investigators website:
http://www.jyi.org/features/ft.php?id=1327
Gavin, M. L., & Black, J. D. (2008). Caffeine. Retrieved October 19, 2010, from The
Nemours Foundation website:
http://kidshealth.org/teen/drug_alcohol/drugs/caffeine.html#
Kovacs, B., & Stoppler, M. C. (n.d.). Caffeine. In Caffeine [Caffeine, Health Effects,
Statistics]. Retrieved October 5, 2010, from MedicineNet website:
http://www.medicinenet.com/caffeine/article.htm
Lieberman, H. R., Tharion, W. J., Shukitt-Hale, B., Speckman, K. L., & Tulley, R. (n.d.).
Biomedical and Life Sciences. In Effects of Caffeine on Sleep loss, and Stress on Cognitive
Performance and Mood During U.S. Navy SEAL Training [Caffeine, Effects ]. Retrieved
October 5, 2010, from SpringerLink website:
http://www.springerlink.com/content/2bjn0v6dg712phw5/
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Please feel free to ask any questions
regarding my experiment.