The Effect of Juices
on the Longevity of
Drosophila
melanogaster
Linsey Nowack
Nowack
Table of Contents
Acknowledgments………………………………………………………………………………… 1
Purpose and Hypothesis…………………………………………………………………………... 2
Review of Literature……………………………………………………………………………… 3-5
Materials and Methods of Procedure……………………………………………………………...6-11
Results…………………………………………………………………………………………….12-17
Data Tables……………………………………………………………………………….12-14
T Test Results…………………………………………………………………………….15
Graphs……………………………………………………………………………………16
Conclusion………………………………………………………………………………………...19-22
Reference List…………………………………………………………………………………….23-24
Nowack
Acknowledgments
I would like to thank my family for their unyielding support, especially my older sister, Lea. In addition,
I’d like to thank Stevenson High School for providing equipment such as test tubes and test tubes stands.
Finally, I’d like to thank Mrs. Regussa and my sponsor, Mrs. Palffy. No words can express the gratitude I
feel towards them for guiding me through this wonderful, scientific expedition.
Nowack
Purpose
The purpose of this experiment is to test the Free Radical Theory along with the properties of various
fruits and vegetables operating the life span of Drosophila melanogaster. The Free Radical Theory relies
on antioxidants found in consumed foods to prevent/decelerate oxidative stress on a cell’s organelles and
DNA. Therefore, by providing D. melanogaster with foods- consisting of juices and the standard D.
melanogaster food mixture- of various antioxidant properties, the Drosophila melanogaster with greater
supply of antioxidants would, in theory, live longer.
Hypothesis
If D. melanogaster were provided diets of D. melanogaster mix and carrot juice, mango juice, peach
juice, pear juice, or water, then the D. melanogaster given food with carrot juice will have the longest
lives.
Nowack
Review of Literature
Drosophila melanogaster have a variety of roles ranging from pesky household annoyances to
one of the most beneficial organism in biological research. These insects slapped for hovering around
human food were once studied by Thomas Hunt Morgan, in 1910, to recognize many main rules of
heredity such as the use of sex-linked genes as well as dominant and recessive traits (Wade
2000)(“Thomas” 2006). Due to the D. melanogaster’s simplicity, it was the first organism to have its
entire genetic code mapped lead by Dr. J. Craig Venter of the Celera Corporation in December of 1999
(Wade 2000). Today, D. melanogaster are still the one of the most popular organisms for genetic
research.
Drosophila comes from the term “lover of dew” because D. melanogaster can be found around
decaying organic material. They like to lay their eggs on the slightly old fruit so the larvae can use the old
fruit as a source of nutrition after hatching (Miller 2000). Female D. melanogaster live an average 26
days while males live around 33 days in lab conditions. They prefer a temperature of 25°C which will
take around 10 days for the D. melanogaster to mature from egg to adult. Anything below 25°C will slow
the process (The University of Arizona Center for Insect Science Education Outreach 2001).
D. melanogaster remain eggs for the first 22 hours of their lives. Once hatching from its egg, the
insect enters a larval stage which lasts about 4 days (The University of Arizona Center for Insect Science
Education Outreach 2001). Larvae are usually small, thin, and a pale white with black tips. They can be
found inside and on top of the food (“Drosophila” 2011). Afterwards, the larvae harden and become
pupas. In the pupa stage, they enclose themselves in small brown cocoons. After 4-6 days, the D.
melanogaster enter adulthood (The University of Arizona Center for Insect Science Education Outreach
2001).
In 2010, another experiment was conducted by the Laboratory of Experimental Gerontology,
National Institute on Aging, with D. melanogaster regarding their longevity. It focused on what foods
placed in the D. melanogaster diet could elongate the insect’s lifespan. Past experiments have suggested
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diets of extracts from blueberries, acai fruit pulp, or even cranberries combined with oregano could
extend the lives of D. melanogaster. This experiment, in particular, questioned the qualities of nectarines.
As a subspecies of peaches, nectarines contain “a number of nutritionally important heath-promoting
ingredients, including dietary fiber, meaningful amounts of vitamin C and and β- carotenoids, and high
contents of polyphenols (Boyd 2011).” In the procedure, 10 D. melanogaster were placed per vial. The
males and females were allowed to mate and then were separated into different vials. The number of eggs
produced as well as the amount of movement was measured. It’s “findings suggest that nectarine can
promote longevity without affecting food intake, and this life span extension depends on gender and
dosage of nectarine (Boyd 2011).”
The Laboratory of Experimental Gerontology was testing the possible influence of free radicals.
This theory, hypothesized in 1956 by Denam Harman, relies on the idea that aging is caused by free
radicals creating oxidative stress on macromolecules in the cell (Panno 2005)(Boyd 2011). Free radicals
are molecules released by the mitochondria with an unpaired electron. One of the most dangerous free
radical is the oxygen free radical due to its ability to take an electron from almost any molecule in the
cell. Upon doing so, the free radical can cause a “reaction of destabilized molecules reacting with other
molecules to form new free radicals and a variety of potentially dangerous compounds (Panno 2005).” In
order to defend itself from such damage, cells contain the enzyme superoxide dismutase (SOD). It
neutralizes newly made oxygen free radicals. However, there are always some oxygen free radicals that
escape the watchful of eye of SOD and their damage cumulates overtimes thus creating oxidative stress.
By consuming foods of antioxidant qualities, one could, in theory, prevent some oxidative damage and
live longer. Genetic studies of Saccharomyces cereviside, Musca domestica, Drosophila melanogaster,
and Mus musculus have found many genes engaged in changing their suitor’s lifespan (Panno 2005).
Antioxidants can be found in a variety of foods and in different forms. Vitamin A and Vitamin C
are antioxidants. A past experiment’s results even suggested Vitamin E can protect lab animals from
biochemical threats such as cigarette smoke and metallic poison. However, it has difficulty entering the
mitochondria of a cell and therefore can’t defend that organelle’s DNA (Kidd 2006). The following
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experiment, instead of testing nectarine, experiments with diets with Daucus carota, Mangifera, Prunus
persica, or Pyrus juice. D. carota are sometimes considered the superfood of vegetable. In juice form, one
cup “can offer a quick energy boost with its 2 grams of protien, 2 grams of fiber, and only 94 calories.
The beta carotene fix measures up 25,833 IU along with a healthy dose of vitamins B1, B2, B3, B6 and 9
mcg of folic acid (And 2011).” “Beta carotene is a strong, natural antioxidant that helps functions of
reproductions, vision, maintenance of epithelial integrity, growth, and development (Power 2011).” One
cup of D. carota juice also contains 56.6 mg of calcium and 689 mg of potassium along with 20.1 mg of
vitamin C and a little of iron and zinc (And 2011).
Mangifera, like D. carota, is another powerful food packed with many enzymes that help defend
itself from insects. These enzymes, in humans, stimulate metabolism and cleanse the intestinal tract
(Mango 2011). In addition “studies have shown that foods containing phenolic compounds have powerful
antioxidant, anticancer, anticardiovascular abilities. [Mangifera] possess the phenols quercetin,
isoquercitfin, astragalin, fiseti, gallic acid, and methylgallat (Mango 2011).” Furthermore, Mangifera also
contain lots of beta carotene realm, potassium, magnesium, vitamin C, and impressive numbers of
vitamins B1, B2, B3, and B6 with a bit of zinc, iron, and calcium (Mango 2011).
With high quantities of carotenes and known anticancerous properties, P. perisca juice was
chosen to be tested in this experiment because it was similar to the Laboratory of Experimental
Gerontology’s experiment involving nectarines, a subspecies of peaches (Properties 2011). P. perisca
contain lots of vitamin A, B vitamins, vitamin C, calcium, fiver, potassium, and a pinch of zinc along
with beta carotene (It’s 2011).
Last but not least, Pyrus is known to be high in fiber with fair amount of vitamins A, C, K, B2,
B3, and B6. Like P. perisca, Pyrus contain calcium, magnesium, potassium, copper, and manganese. It
also contains another antioxidant by the name of quercetin in its skin which “helps prevent cancer and
artery damage that can lead to help problems (Pear 2011).”
Nowack
Materials and Methods of Procedure
Materials:

1 packet of Ward’s package with Drosophila melanogaster and food

5 400ml plastic containers- with lids

1 role of labeling tape

150 thin test tubes

76 cotton balls

5 large test tubes with personal sponge corks

1 black Sharpie marker

1 red Crayola marker

1 green Crayola marker

1 liter carton of Hortex: Vitaminka carrot juice

1 liter carton of Nectar Hekmap: Florina peach juice

1 liter carton of Premium: Fresh Nectar pear juice

1 liter carton of Nectar Hekmap: Florina mango juice

1role of paper towels- perforated every 25 cm

6 plastic spoons

1sheet of paper

1 pair of scissors

18 wooden test tube racks that hold 6 test tubes

1 rack that holds 8 test tubes by 10 test tubes

1 graduated cylinder

1 napkin

1 functional sink
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
1 bottle of Dial Complete: antibacterial foaming hand soap

Water

1 plastic bin

1 test tube brush

14.78 milliliters of Clorox bleach
Sanitizing test tubes
1. Gather all large and small test tubes that will be used in the experiment
2. Remove the test tubes’ caps or corks and set them aside
3. Fill a plastic bin with 3.78541178 liters of warm water
4. Pour 14.7867648 milliliters of bleach into the plastic bin and stir so the bleach dissolves into the
water
5. Wait 2 minutes before placing the test tubes in the bin
6. Let test tubes soak for 15 minutes before removing them from the plastic bin
7. Squirt some soap into each test tube and brush the inside using a test tube brush
8. Rinse test tubes with tap water and set them on wooden test tube racks to dry
9. Place paper towels underneath the test tube racks to prevent puddles of water
10. Drain bleach and water from the plastic bin into a sink
Preparing D. melanogaster food
All food is made at the same time and then stored in a refrigerator at 6°C to prevent the growth of
bacteria or fungi.
1. Gather 5 400ml plastic containers and their lids and place them in a line on a flat surface
2. Write ‘carrot’ on a piece of labeling tape using a black Sharpie marker, cut it from the role of
labeling tape, and insert it on the first container
3. Do the same for the second container, but this time label it ‘mango’
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4. Label the third container ‘peach’, the fourth container ‘pear’, and the last container ‘control’
5. Cut open the top of Ward’s D. melanogaster food bag and divide the food equally among the 5
400ml plastic containers
6. Measure the amount of food in one container
7. Pour Hortex: Vitaminka carrot juice in the first container labeled ‘carrot’ with the of amount food
and the amount of juice in a 1:1 ratio
8. Pour Nectar Hekmap: Florina mango juice in the second container labeled ‘mango’ with the
amount of food and the amount juice in a 1:1 ratio
9. Pour Nectar Hekmap: Florina peach juice in the third container labeled ‘peach’ with the amount
of food and the amount juice in a 1:1 ratio
10. Pour Premium: Fresh Nectar pear juice in the fourth container labeled ‘pear’ with the amount of
food and the amount of juice in a 1:1 ratio
11. Pour water in the last container labeled ‘control’ with the amount of food and the amount of water
in a 1:1 ratio
12. Use a plastic spoon to mix the containers (each container gets its own plastic spoon)
13. Once all the foods have been mixed, place a lid on each container
14. Store all containers and cartons of juice in a refrigerator at 6°C
15. Wash all the plastic spoons that were used to mix the foods with soap and water until no food
remains are visible on the spoons
16. Dry the spoons using a napkin and place them alongside the containers in the refrigerator
Isolating adults from children
The goal is to separate the adults from the pupas, larvae, and eggs because data will later be
gathered from the pupa once they’ve changed into adults. All D. melanogaster are stored at 23°C.
Nowack
1. Gather 1 large test tube with a sponge cap, 1 sheet of paper, the ‘control’ container of D.
melanogaster, 1 plastic spoon from the refrigerator, and the test tube holding the Ward’s D.
melanogaster
2. Use the spoon to transfer one spoonful of control food from the control container into the empty
large test tube (Test Tube B)
3. Fold sheet of paper into the shape of a funnel
4. Place smaller end of the funnel into Test tube A so that the larger opening of the funnel faces
upward
5. Lightly shake the test tube holding the D. melanogaster (Test Tube A) so that all the adult D.
melanogaster fall to the bottom of the test tube
6. Quickly remove the cork from Test Tube A and turn the test tube upside down over the large
opening of the tunnel
7. Ensure there are no gaps for the insects to escape between either test tubes and the funnel by
placing one hand on the spot where Test Tube A and large opening to the funnel connect in order
to hold the two together and another hand on the spot where the small opening to the funnel and
Test Tube B connect
8. Lightly shake/tap the test tubes connected by the funnel against the hard surface bellow so the
adult D. melanogaster fall through the funnel opening and into Test Tube B- this will also prevent
the adults from crawling back up the funnel once they’ve fallen into Test Tube B
9. After all the adults are all in Tube B, quickly set Test Tube A reside up again on a hard surface,
remove the funnel from Test Tube B, and place a sponge cork on Test Tube B
10. Plug Test Tube A with its own cork
11. Check to make sure no D. melanogaster are stuck in the funnel- if there are, use the plastic spoon
to move them into Test Tube B (remember to shake test tube so adults fall to the bottom before
removing cork to prevent any from escaping)
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Relocating newly transformed pupas
This is a daily process performed until all 150 small test tubes are filled.
1. Check to see if any pupas have changed into adults in Test Tube B
2. If so, gather one empty large test tube and its sponge cork
3. Repeat steps from the “Isolating adults from children” section- the goal is again to separate the
adults from the pupas, larvae, and eggs except:

Do not put control food in the new large test tube (Test Tube C) because it isn’t the
adults’ permanent home
4. After moving the new adults to their own test tube, remember to cork both test tubes B and C
5. Gather all food containers and all spoons from the refrigerator
6. Also collect one more spoon and a sheet of paper towel from the paper towel role by ripping it
off along the perforated line
7. Lay the paper towel where the transferring will take place
8. Count the amount of flies in the test tube and take out that many small test tubes
9. Gather wooden six test tube stands
10. Grab a hand full of cotton balls
11. Use a pair of scissors to cut each cotton ball in half
12. Use a black Sharpie marker and labeling tape to label each test tube
13. Each test tube will be filled with a different type of food; therefore, label each test tube the food it
will be holding in the order of ‘carrot’, ‘mango’, ‘peach’, ‘pear’, then ‘control’
14. Underneath the type of food, write the date of when the pupas changed into adults (today’s date)
15. Wash your hands with soap and water and dry them
16. Place the smaller test tubes that will be used on wooden test tube racks
17. Fill the small test tubes with ____ of the type of food it’s labeled for using a spoon
18. Each type of food gets its own spoon
Nowack
19. The food will be difficult to fit through the opening of the test tube, so role them into small
spheres that can be dropped into the test tube
20. Wash hands when switching between types of food in order to not contaminate the food
21. To move the D. melanogaster, lightly shake Test Tube C so they all are at the bottom of the test
tube then remove the cork and let one D. melanogaster crawl out onto a clean plastic spoon
22. Re-cork Test Tube C and carefully place the D. melanogaster from the spoon into one of the
smaller test tubes
23. Plug the smaller test tube using one half of a cotton ball
24. Repeats steps 21-23 until all D. melanogaster of Test Tube C has its own small test tube
25. Wash all spoons using soap and water and dry using a sheet of paper towel
26. Recap food containers and return them, along with the spoons, back into the refrigerator
Gathering data
1. Every day, check to see if any of the D. melanogaster in the small test tubes died
2. If so, mark the date of the death above the type of food and color the sides of the labeling tape red
using a red Crayola marker
3. Once all 150 small test tubes are filled, organize them by type of food in order to make gathering
data easier
4. Number each test tube in the order of when the D. melanogaster became adults from oldest (#1)
to youngest (#30) for each type of food using a green Crayola marker
Nowack
Results: data tables
Raw Data Tables
Effect of Fruit/Vegetable on the Longevity of Fruit Flies
Type of food
Fly Number
Date Born
Date Died
NDL
Effect of Fruit/Vegetable on
the Longevity
of Fruit Flies
1 the
28-Nov of
8-Dec
10
Effect of Fruit/Vegetable on
Longevity
Fruit Flies
Type of food
Fly Number
Date Born
Date Died
NDL 30
28-Nov Date
28-Dec NDL
Type of food
Fly Number 2 Date Born
Died
1
28-Nov
8-Dec
10
28-Nov
19-Dec
21
13
28-Nov
8-Dec
10
2
28-Nov
28-Dec
30
29-Nov
23-Dec
24
24
28-Nov
28-Dec
30
3
28-Nov
19-Dec
21
29-Nov
16-Dec
17
35
28-Nov
19-Dec
21
4
29-Nov
23-Dec
24
29-Nov
10-Dec
11
46
29-Nov
23-Dec
24
5
29-Nov
16-Dec
17
30-Nov
23-Dec
23
57
29-Nov
16-Dec
17
6
29-Nov
10-Dec
11
30-Nov
7-Jan
39
68
29-Nov
10-Dec
11
7
30-Nov
23-Dec
23
1-Dec
16-Dec
15
79
30-Nov
23-Dec
23
30-Nov
7-Jan
39
10
1-Dec
30-Dec
29
88
30-Nov
7-Jan
39
1-Dec
16-Dec
15
11
1-Dec
30-Dec
29
99
1-Dec
16-Dec
15
10
1-Dec
30-Dec
29
12
1-Dec
7-Dec
6
10
1-Dec
30-Dec
29
11
1-Dec
30-Dec
29
13
2-Dec
26-Dec
24
11
1-Dec
30-Dec
29
12
1-Dec
7-Dec
14
2-Dec
5-Dec
12
1-Dec
7-Dec
636
13
2-Dec
26-Dec
24
15
2-Dec
17-Dec
15
13
2-Dec
26-Dec
24
Carrot
14
2-Dec
5-Dec
16
2-Dec
20-Dec
18
14
2-Dec
5-Dec
33
15
2-Dec
17-Dec
15
17
3-Dec
8-Dec
5
15
2-Dec
17-Dec
15
Carrot
Carrot
16
2-Dec
20-Dec
18
18
2-Dec
5-Dec
3
16
2-Dec
20-Dec
18
17
3-Dec
8-Dec
19
3-Dec
16-Dec
13
17
3-Dec
8-Dec
55
18
2-Dec
5-Dec
20
3-Dec
30-Dec
27
18
2-Dec
5-Dec
33
19
3-Dec
16-Dec
13
21
3-Dec
25-Dec
22
19
3-Dec
16-Dec
13
20
3-Dec
30-Dec
27
22
3-Dec
8-Dec
5
20
3-Dec
30-Dec
27
21
3-Dec
25-Dec
22
23
3-Dec
23-Dec
20
21
3-Dec
25-Dec
22
22
3-Dec
8-Dec
24
3-Dec
16-Dec
13
22
3-Dec
8-Dec
55
23
3-Dec
23-Dec
20
25
4-Dec
16-Dec
12
23
3-Dec
23-Dec
20
24
3-Dec
16-Dec
13
24
3-Dec
16-Dec
13
26
4-Dec
31-Dec
27
25
4-Dec
16-Dec
12
25
4-Dec
16-Dec
12
27
5-Dec
17-Dec
12
26
4-Dec
31-Dec
27
26
4-Dec
31-Dec
27
28
5-Dec
28-Dec
23
27
5-Dec
17-Dec
12
27
5-Dec
17-Dec
12
29
5-Dec
8-Dec
3
28
5-Dec
28-Dec
23
28
5-Dec
28-Dec
23
30
7-Dec
23-Dec
15
29 Average
5-Dec
8-Dec 17.13333
29
5-Dec
8-Dec
33
30
7-Dec
23-Dec
15
30
7-Dec
23-Dec
15
Average
17.13333
Average
17.13333
> 30 days
30 days
days
>> 30
longest
longest
longest
ones
not dead yet
oneslarvae
not dead
dead yet
yet
ones
not
had
had larvae
larvae
had
average
average
<average
10 days
10 days
days
<< 10
Type of food
Type of food
Type of food
Mango
Mango
Mango
Fly Number
Date Born
Date Died
NDL
1
28-Nov
7-Jan
41
Fly Number 2 Date Born
Date Died
NDL 26
28-NovDate
Fly Number
Date Born
Died24-DecNDL
1
28-Nov
7-Jan
41
29-Nov
18-Dec
19
13
28-Nov
7-Jan
41
2
28-Nov
24-Dec
26
29-Nov
1-Jan
33
24
28-Nov
24-Dec
26
3
29-Nov
18-Dec
19
29-Nov
11-Jan
43
35
29-Nov
18-Dec
19
4
29-Nov
1-Jan
33
29-Nov
11-Jan
43
46
29-Nov
1-Jan
33
5
29-Nov
11-Jan
43
30-Nov
25-Dec
25
57
29-Nov
11-Jan
43
6
29-Nov
11-Jan
43
30-Nov
23-Dec
23
68
29-Nov
11-Jan
43
30-Nov
25-Dec
25
1-Dec
7-Dec
6
797
30-Nov
25-Dec
25
30-Nov
23-Dec
23
10
1-Dec
1-Jan
31
88
30-Nov
23-Dec
23
1-Dec
7-Dec
11
1-Dec
23-Dec
22
99
1-Dec
7-Dec
66
10
1-Dec
1-Jan
31
12
1-Dec
26-Dec
25
10
1-Dec
1-Jan
31
11
1-Dec
23-Dec
22
13
2-Dec
28-Dec
26
11
1-Dec
23-Dec
22
12
1-Dec
26-Dec
25
14
2-Dec
5-Dec
3
12
1-Dec
26-Dec
25
13
2-Dec
28-Dec
26
15
2-Dec
19-Dec
17
13
2-Dec
28-Dec
26
14
2-Dec
5-Dec
16
2-Dec
30-Dec
28
14
2-Dec
5-Dec
33
15
2-Dec
19-Dec
17
18
3-Dec
30-Dec
27
15
2-Dec
19-Dec
17
16
2-Dec
30-Dec
28
19
3-Dec
30-Dec
27
16
2-Dec
30-Dec
28
18
3-Dec
30-Dec
27
20
3-Dec
20-Dec
17
18
3-Dec
30-Dec
27
19
3-Dec
30-Dec
27
21
3-Dec
23-Dec
20
19
3-Dec
30-Dec
27
20
3-Dec
20-Dec
17
22
3-Dec
23-Dec
20
20
3-Dec
20-Dec
17
21
3-Dec
23-Dec
20
23
3-Dec
10-Dec
7
21
3-Dec
23-Dec
20
22
3-Dec
23-Dec
20
24
4-Dec
2-Jan
28
22
3-Dec
23-Dec
20
23
3-Dec
10-Dec
25
4-Dec
8-Dec
23
3-Dec
10-Dec
747
24
4-Dec
2-Jan
28
26
4-Dec
10-Dec
6
24
4-Dec
2-Jan
28
25
4-Dec
8-Dec
25
4-Dec
8-Dec
44
27
3-Dec
31-Dec
28
26
4-Dec
10-Dec
26
4-Dec
10-Dec
66
28
3-Dec
31-Dec
28
27
3-Dec
31-Dec
28
27
3-Dec
31-Dec
28
29
5-Dec
26-Dec
21
28
3-Dec
31-Dec
28
28
3-Dec
31-Dec
28
30
7-Dec
28-Dec
21
29
5-Dec
26-Dec
21
29
5-Dec
26-Dec
21
31
2-Dec
2-Jan
30
30 Average
7-Dec
28-Dec 23.16667
21
30
7-Dec
28-Dec
21
31
2-Dec
2-Jan
30
2-Dec
2-Jan
30
had larvae: 1731
2-Dec
Average
23.16667
Average
23.16667
hadlarvae:
larvae:17
17
2-Dec
had
2-Dec
Nowack
Type of food
Fly Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
24
25
26
27
28
29
30
Peach
had larvae: 23
Date Born
Date Died
NDL
28-Nov
16-Dec
18
28-Nov
23-Dec
25
29-Nov
4-Jan
36
29-Nov
2-Jan
34
29-Nov
27-Dec
28
30-Nov
28-Dec
28
30-Nov
24-Dec
24
30-Nov
23-Dec
23
1-Dec
5-Jan
35
1-Dec
4-Dec
3
1-Dec
24-Dec
23
1-Dec
30-Dec
29
2-Dec
27-Dec
25
2-Dec
23-Dec
21
2-Dec
11-Jan
40
2-Dec
28-Dec
26
2-Dec
7-Jan
36
2-Dec
7-Jan
36
3-Dec
28-Dec
25
3-Dec
30-Dec
27
3-Dec
23-Dec
20
3-Dec
10-Dec
7
3-Dec
4-Jan
32
4-Dec
9-Jan
36
4-Dec
8-Dec
4
4-Dec
26-Dec
22
5-Dec
8-Dec
3
5-Dec
28-Dec
23
7-Dec
25-Dec
20
Average
24.44828
3-Dec
Type of food
Type of food
Pear
Fly Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Control
Fly Number
had larvae 24
25
26
27
28
29
30
Date Born
Date Died
NDL
28-Nov
23-Dec
25
29-Nov
6-Dec
7
29-Nov
22-Jan
54
29-Nov
23-Dec
24
29-Nov
25-Dec
26
30-Nov
12-Dec
12
30-Nov
17-Dec
17
1-Dec
16-Dec
15
1-Dec
7-Jan
38
1-Dec
1-Jan
31
1-Dec
21-Jan
51
2-Dec
10-Jan
39
2-Dec
5-Dec
3
2-Dec
20-Dec
18
2-Dec
30-Dec
28
2-Dec
27-Dec
25
2-Dec
5-Dec
3
3-Dec
20-Dec
17
3-Dec
20-Dec
17
3-Dec
16-Dec
13
3-Dec
7-Dec
5
3-Dec
7-Dec
5
3-Dec
16-Dec
13
4-Dec
10-Dec
6
4-Dec
17-Dec
13
5-Dec
7-Dec
2
5-Dec
10-Dec
5
5-Dec
16-Dec
11
5-Dec
20-Dec
15
28-Nov
29-Nov
1
Average
17.96667
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
Date Born
Date Died
NDL
28-Nov
4-Jan
28-Nov
23-Dec
29-Nov
26-Dec
29-Nov
20-Dec
29-Nov
1-Dec
30-Nov
23-Dec
30-Nov
25-Dec
30-Nov
26-Dec
1-Dec
1-Jan
1-Dec
23-Dec
1-Dec
24-Dec
1-Dec
16-Dec
2-Dec
30-Dec
2-Dec
30-Dec
2-Dec
27-Dec
2-Dec
15-Jan
2-Dec
28-Dec
2-Dec
30-Dec
3-Dec
23-Dec
3-Dec
28-Dec
3-Dec
30-Dec
3-Dec
28-Dec
3-Dec
5-Jan
3-Dec
1-Jan
4-Dec
4-Jan
4-Dec
30-Dec
4-Dec
26-Dec
5-Dec
28-Dec
5-Dec
29-Dec
5-Dec
23-Dec
Average
37
25
27
21
2
23
25
26
31
22
23
15
28
28
25
44
26
28
20
25
27
25
33
29
31
26
22
23
24
18
25.3
Nowack
Data Tables Identifying Outliers
In this experiment, outliers were regarded as D. melanogaster that died early due to injuries from the
transferring process, from drowning in small puddles produced by the food, or from having the food fall
on itself. The column labeled NDL stands “Number of Days Lived (in adult life).”
Type of food
Fly Number
1
2
3
4
5
6
7
8
9
10
11
Carrot
13
2-Dec
26-Dec
24
15
16
2-Dec
2-Dec
17-Dec
20-Dec
15
18
19
20
21
3-Dec
3-Dec
3-Dec
16-Dec
30-Dec
25-Dec
13
27
22
23
24
25
26
27
28
3-Dec
3-Dec
4-Dec
4-Dec
5-Dec
5-Dec
23-Dec
16-Dec
16-Dec
31-Dec
17-Dec
28-Dec
20
13
12
27
12
23
30
7-Dec
Average
1-Dec
2-Dec
3-Dec
2-Dec
3-Dec
5-Dec
23-Dec
15
20.375
6
3
5
3
5
3
12
14
17
18
22
29
> 30 days
longest
outlier
had larvae
average
< 10 days
Date Born
Date Died
NDL
28-Nov
8-Dec
10
28-Nov
28-Dec
30
28-Nov
19-Dec
21
29-Nov
23-Dec
24
29-Nov
16-Dec
17
29-Nov
10-Dec
11
30-Nov
23-Dec
23
30-Nov
7-Jan
39
1-Dec
16-Dec
15
1-Dec
30-Dec
29
1-Dec
30-Dec
29
7-Dec
5-Dec
8-Dec
5-Dec
8-Dec
8-Dec
Type of food
Fly Number
1
2
3
4
5
6
7
8
9
10
11
12
13
Mango
Date Born
Date Died
NDL
28-Nov
7-Jan
28-Nov
24-Dec
29-Nov
18-Dec
29-Nov
1-Jan
29-Nov
11-Jan
29-Nov
11-Jan
30-Nov
25-Dec
30-Nov
23-Dec
1-Dec
7-Dec
1-Dec
1-Jan
1-Dec
23-Dec
1-Dec
26-Dec
2-Dec
28-Dec
41
26
19
33
43
43
25
23
6
31
22
25
26
15
16
18
19
20
21
22
23
24
2-Dec
2-Dec
3-Dec
3-Dec
3-Dec
3-Dec
3-Dec
3-Dec
4-Dec
19-Dec
30-Dec
30-Dec
30-Dec
20-Dec
23-Dec
23-Dec
10-Dec
2-Jan
17
28
27
27
17
20
20
7
28
27
28
29
30
31
3-Dec
3-Dec
5-Dec
7-Dec
2-Dec
Average
2-Dec
2-Dec
4-Dec
4-Dec
31-Dec
31-Dec
26-Dec
28-Dec
2-Jan
28
28
21
21
30
25.25925926
5-Dec
8-Dec
10-Dec
3
4
6
had larvae: 17
14
25
26
Nowack
Type of food
Fly Number
1
2
3
4
5
6
7
8
9
Peach
1-Dec
1-Dec
2-Dec
2-Dec
2-Dec
2-Dec
2-Dec
2-Dec
3-Dec
3-Dec
3-Dec
3-Dec
3-Dec
4-Dec
24-Dec
30-Dec
27-Dec
23-Dec
11-Jan
28-Dec
7-Jan
7-Jan
28-Dec
30-Dec
23-Dec
10-Dec
4-Jan
9-Jan
23
29
25
21
40
26
36
36
25
27
20
7
32
36
27
4-Dec
26-Dec
22
29
30
5-Dec
7-Dec
Average
3-Dec
1-Dec
4-Dec
5-Dec
28-Dec
25-Dec
23
20
26.88461538
4-Dec
8-Dec
8-Dec
3
4
3
10
26
28
Fly Number
1
2
3
4
5
6
7
8
9
10
11
12
Control
Type of food
18
25
36
34
28
28
24
23
35
11
12
13
14
15
16
17
18
19
20
21
22
24
25
had larvae: 23
Type of food
Date Born
Date Died
NDL
28-Nov
16-Dec
28-Nov
23-Dec
29-Nov
4-Jan
29-Nov
2-Jan
29-Nov
27-Dec
30-Nov
28-Dec
30-Nov
24-Dec
30-Nov
23-Dec
1-Dec
5-Jan
Date Born
Date Died
NDL
28-Nov
23-Dec
29-Nov
6-Dec
29-Nov
22-Jan
29-Nov
23-Dec
29-Nov
25-Dec
30-Nov
12-Dec
30-Nov
17-Dec
1-Dec
16-Dec
1-Dec
7-Jan
1-Dec
1-Jan
1-Dec
21-Jan
2-Dec
10-Jan
25
7
54
24
26
12
17
15
38
31
51
39
14
15
16
2-Dec
2-Dec
2-Dec
20-Dec
30-Dec
27-Dec
18
28
25
18
19
20
3-Dec
3-Dec
3-Dec
20-Dec
20-Dec
16-Dec
17
17
13
23
3-Dec
16-Dec
13
25
4-Dec
17-Dec
13
28
29
5-Dec
5-Dec
16-Dec
20-Dec
11
15
Average
2-Dec
2-Dec
3-Dec
3-Dec
4-Dec
5-Dec
5-Dec
28-Nov
5-Dec
5-Dec
7-Dec
7-Dec
10-Dec
7-Dec
10-Dec
29-Nov
23.13636364
3
3
5
5
6
2
5
1
13
17
21
22
had larvae 24
26
27
30
Fly Number
1
2
3
4
Pear
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
5
Date Born
Date Died
NDL
28-Nov
4-Jan
28-Nov
23-Dec
29-Nov
26-Dec
29-Nov
20-Dec
30-Nov
30-Nov
30-Nov
1-Dec
1-Dec
1-Dec
1-Dec
2-Dec
2-Dec
2-Dec
2-Dec
2-Dec
2-Dec
3-Dec
3-Dec
3-Dec
3-Dec
3-Dec
3-Dec
4-Dec
4-Dec
4-Dec
5-Dec
5-Dec
5-Dec
Average
29-Nov
23-Dec
25-Dec
26-Dec
1-Jan
23-Dec
24-Dec
16-Dec
30-Dec
30-Dec
27-Dec
15-Jan
28-Dec
30-Dec
23-Dec
28-Dec
30-Dec
28-Dec
5-Jan
1-Jan
4-Jan
30-Dec
26-Dec
28-Dec
29-Dec
23-Dec
37
25
27
21
23
25
26
31
22
23
15
28
28
25
44
26
28
20
25
27
25
33
29
31
26
22
23
24
18
26.10345
1-Dec
2
Nowack
T Test Results
Each type of food’s data was compared to the control group’s results.
Outliers Included Data
Type of food
T Test Score
Carrot
Mango
Peach
Pear
0.79
0.11
0.046
0.013
Outliers Removed Data
Type of food
T Test Score
Carrot
Mango
Peach
Pear
0.37
0.55
0.21
0.25
Nowack
Graphs
Average Days Lived (Outliers Included)
Average Number of Days Lived
30
25
20
15
10
5
0
Carrot
Mango
Peach
Pear
Water
Type of Liquid added to Food Mix
Average Days Lived (Outliers Excluded)
Average Number of Days Lived
30
25
20
15
10
5
0
Carrot
Mango
Peach
Pear
Type of Liquid added to Food Mix
Water
Nowack
Conclusion
The following experiment provided Drosophila melanogaster diets with carrot, mango, peach, or pear
juice, or simply water. Carrot juice, known to be high in many antioxidants, was hypothesized to extend
D. melanogaster’s life the longest. Surprisingly, D. melanogaster on diets with carrot juice lived the
shortest, receiving an average of about 17 days lived including outliers. Excluding the outliers, D.
melanogaster of the carrot juice group still received the lowest average number of days lived, about 20
days.
D. melanogaster that died early due to injuries from the transferring process, from drowning in
small puddles produced by the food, or from having the food fall on itself were considered “outliers”
because their deaths were not influenced by the substance added to their diet. When outliers were
included in the data, D. melanogaster on diets with pear juice had the longest average number of days
lived, about 25 days. When outliers were excluded from the data, D. melanogaster on diets of peach juice
had the longest average number of days lived. Its average, about 26.88 days, exceeded D. melanogaster
on diets of pear juice’s average by merely 0.78 of a day with D. melanogaster on diets of mango juice
following closely behind. However, while the control group did not have the longest average of number
of days lived, its data did include the longest living D. melanogaster of the experiment which lived 54
days, indicating maybe the sugar and acid of the juices had an adverse effect on the D. melanogaster.
Regarding the number of outliers each group of the independent variable had, the control group
and carrot group contained the most. The control group’s data alone resulted in 8 outliers while the pear
group contained the least amount (only 1). Not only did the control group and carrot group result in
surprising quantitative data but also qualitative data. On December 6 of the experiment, some of the carrot
and control vials’ food appeared to be “melting” with a gleam on the surface of the food. On December
17, signs of discoloration were found on the foods of control vial #17 and carrot vial #18. Furthermore, by
December 28 some control vials contained food appearing to melt on others containing food that appeared
Nowack
to be hardening. The same thing was viewed from some carrot vials except the carrot vials appeared to be
a little more mushy before (compared to the other independent variable groups’ vials) and now looked to
be hardening. By the end of the experiment, all independent variable groups’ foods hardened. The fact
that the carrot and control group’s foods hardened faster might have influenced their D. melanogaster’s
longevity.
Including the outliers, t test results proved the pear group and peach group data compared to the
control group results to be statistically significant. The pear group data, in fact, was the most different
from the control group’s data receiving a t test score of 0.013. Data considered “statistically significant”
would have a t test score of less than 0.05. Therefore, the t test scores excluding the outliers are all
considered not statistically significant. All t tests compared the independent variable groups to the control
group. However, considering the control group’s observed considerable variability data ranging from the
shortest living D. melanogaster of the entire experiment (1 day old) to the longest living D. melanogaster
of the entire experiment (54 days old), the control group is relatively unstable to be used as a stable
comparison to the other groups’ data.
The outliers being removed from the data proved to be extremely influential to whether or not the
data proved to be statistically significant. Therefore, the experimental errors are those that allowed such
outliers to exist in the first place. For example, some outliers were those that later produced eggs in their
test tube. The experiment error was allowing them to reproduce in the first place, and the solution would
be to isolate the new adults the moment they appear. Other outliers would be those injured during the
transferring process and those injured by their food. While these incidents cannot entirely be avoided, the
way the food is placed and the temperature the food is placed in can be changed. The food, instead of
stacked, small spheres, could be just one large sphere, and perhaps the carrot and control foods melted
because they couldn’t adjust from refrigerator temperature to room temperature. Another experimental
error would be the temperature the D. melanogaster were kept at. While they were all placed in the same
temperature, the environment’s temperature changed sometimes rising/falling one or two degrees between
Nowack
days, and this might have impacted the D. melanogaster. The solution would be to find an environment
with a more controllable temperature. Furthermore, the quality of the food in this experiment could be
improved in further experiments (i.e. prevent food hardening and discoloration); however, the means of
improving the food quality are uncertain. The number of D. melanogaster also made this experiment
statistically challenging; nonetheless, because of the number of outliers, this number was insufficient to
contain statistically significant results. While it would be challenging to increase the total number of flies
because it involves more test tubes and more transferring that can be overwhelming and may decrease the
quality of the transfer of the process early in the experiment, perhaps the experiment could have more
statistically significant results by testing less groups of independent variables with more D. melanogaster
per group, such as 3 groups of 50 rather than 5 groups of 30.
While this experiment tested the Free Radical Theory on D. melanogaster, other theories such as
the Calorie Restriction Theory could be tested on D. melanogaster and then compared to this
experiment’s results. Or, this same experiment could be conducted and see if the effects of carrot, mango,
peach, and pear juices are influenced by the gender of the D. melanogaster. Another possibility to extend
this experiment is to compare the effects of carrot, mango, peach, and pear juices on D. melanogaster at
different temperatures to see if the temperature affects the food Future experiments can also test different
concentration levels of the juice’s effect on longevity. While this experiment can be extended by testing
the juices’ effects on other organisms and comparing it to D. melanogaster, what’s nice about this species
is that it has an efficiently measurable longevity with days. It’s not too short (which would require a lot of
attention), and it’s not too long (in years which would make the experiment take a very long time to
conduct).
Although the following experiment didn’t exactly prove one food extended D. melanogaster
longevity more than another, the independent variable’s different groups did succeed in getting different
results, such as the carrot group did not receive the same average number of days lived as the mango
group, proving a diet is influential to one’s longevity. Furthermore, the experiment was run on animals,
Nowack
and, on average, they seem to benefit from some fruit juice in their diet. Although the fruit juice does not
seem to be a “fountain of youth” that abnormally extends longevity and does not seem to prevent infant
mortality, perhaps this observation extends to more complex animals. It would be interesting to see if the
same trend applies to other kingdoms.
Nowack
Reference List
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http://www.vegparadise.com/highestperch412.html
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Kern, and Sige Zou. (2011, March) Nectarine Promotes Longevity in Drosophila Melanogaster.
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