Effect of high carbohydrate diet on the growth and reproduction of Drosophila
melanogaster species
Annette Massihi and Arpi Azarian
Department of Biological Science
SaddleBack College
Mission Viejo, CA 92692
Abstract
The project focuses on the effect of high carbohydrate diet on the
reproduction/survival rate of Drosophila melanogaster. Hypothesis tested is that fruit
flies with regular diet have greater reproduction and survival rate. For conducting the
experimetn 360 wingless fruit flies were divided into two groups of 180 where the first
group had high carbohydrates (with maple syrup) and the other group had regular nutrient
diet. For four weeks each group was kept in nine different vials of 20 (10 males and 10
females). Light microscope was used for data collection. Through statistical analysis a
comparison of larva, pupa and adult rate was conducted. The average rates of regular diet
group for larva, pupa and adult production for the first generation was (130±126, 81±77,
67±64), and (112±108, 69±65, 47±44) for high carb diet. For the second generation the
values were (161±158, 96±92, 80±76) for regular food diet, and (101±98, 45±41, 26±23)
for high-carb diet. The result showed that the reproduction and development rate of the
group with regular diet had higher rate of survivals in different life stages compared to
the group with high carbohydrate diet.
Introduction
Development and reaching to sexual maturation to reproduce is most crucial aspect of an
animal life that is directly connected to nutrition and growth. A comparison of the
lifespan and egg production showed that longevity is commonly expected to trade off
beside reproductive effort and a low carbohydrate and protein diet results in lower
longitivity and higher egg reproduction (Lee et al., 2008). Carbohydrates are energy
source for many important reactions in live organisms and a low carbohydrate intake
restricts an organism’s available energy and slows down growth and regeneration,
thereby altering survival and health (Lushchak et al., 2014).
Based on the recent demographic experiments moderate nutrient manipulation in
adult Drosophila affects mortality rate in a reversible manner, which suggests that dietary
restriction in Drosophila increases lifespan through a reduction of the risk of death rather
than a slowing of aging-related damage (Pletcher et al., 2005). Moreover, sucrose that is
commonly used in recipes of Drosophila laboratory food as a source of carbohydrate may
shorten life span and lower egg-laying capability on the diets with very low protein
content and high in carbohydrates (Lushchak et al., 2014). Adverse effects of high
sucrose diet on fly development and viability may concern control of fly metamorphosis
mediated by insulin signaling. (Rovenko et al.,2015). Lifespan extension by dietary
restriction should not be thought of as a simple trade-off with fecundity even though such
extension is often accompanied by fecundity reduction and even though such
manifestation of longevity vs. reproduction trade-off is to be expected from the
evolutionary standpoint (Dick et al., 2011).
The hypothesis being tested states that fruit files with regular food diet will have
greater reproduction and survival rate in different life stages compare to the fruit flies
with high carbohydrate food diet.
Materials and Methods
The research project was performed over a period of four weeks. A total of 360
Drosophila melanogaster fruit flies were divided into two groups of 180 with different
dietary nutrients. One group had nutrients that contain high level of carbohydrate, which
was made by adding organic maple syrup to the flies’ usual food source. The other group
had regular nutrients without maple syrup. Each group was kept in nine different vials of
20 (10 males and 10 females) to avoid crowdedness and facilitate random mating.
Specified dietary nutrients were provided to every group and then waited for the adult
Drosophila to lay egg. Yeast paste was used in each fruit fly vial to induce their
reproduction and egg laying ability. Usually, it took about 3-4 days for the adult
Drosophila to lay eggs and 7-10 days for the eggs to become adults. A microscope was
used for counting the larva, pupa and adults of the fruit flies, and fly nap was used to
inactivate the new generation of fruit flies for a short period of time in order to count
them by placing the flies on pitri dishes. In addition, water soap was used to kill the old
generation. Once the old generation laid eggs; thereafter, the old generation was killed
and the new generation’s larva, pupa and adults were counted to see how high
carbohydrate nutrient environment has affected on the fruit flies survival and
reproduction rate. The data were put on Microsoft Excel and the differences in the
survival and reproduction rate between the groups with regular and high carb diet were
observed. Using statistical tools such as such as stat plus, an unpaired one-tail t-test was
done for both groups based on the collected data. This was done to see if there was a
significant difference between the survival and reproduction rate of fruit flies with regular
nutrient and high carb nutrient.
Results
The results of this experiment were gained during the four weeks of experiment for two
generations of the fruit flies with two different flies. For each generation the number of
Larva, pupa and Adult was counted for both groups. The data from the first generation of
flies with high carb food is demonstrated in Table 1a and the data from the first
generation of flies with regular food is demonstrated in Table 2b. Table 2a and Table 2b
demonstrate the results gained from the second generation for two diet groups.
Table 1a: High Carb food diet Results
1st Generation
Vials Larva Pupa Adult
1
130
66
48
2
90
45
35
3
88
70
28
4
96
58
34
5
118
73
52
6
108
45
33
7
100
90
73
8
135
69
45
9
129
89
66
Table 2a: High Carb food diet Results
2nd Generation
Vials Larva Pupa Adult
1
70
30
16
2
93
34
21
3
75
66
32
4
63
52
26
5
129
45
23
6
99
43
30
7
134
40
31
8
107
34
22
9
127
42
18
Table 1b: Regular food diet Results
1st Generation
Vials Larva Pupa Adult
1
101
80
72
2
168
74
61
3
128
67
65
4
80
45
38
5
113
89
59
6
148
88
76
7
99
95
80
8
179
90
77
9
139
85
65
Table 2b: Regular food diet Results
2nd Generation
Vials Larva Pupa Adult
1
169
80
70
2
110
76
66
3
148
66
50
4
190
99
83
5
105
89
78
6
200
105
90
7
140
95
80
8
138
101
88
9
240
139
100
Statistical analysis was used for calculating the results of the experiment. The figure
below (Figure 1) displays the average larva, pupa and adult generation numbers for the
flies on regular and high carbohydrate food diet for the first generation. The production
rate was higher for the group on the regular food diet than the group on high carbohydrate
diet. The rate production for larva, pupa and adult for regular food diet was ((130±126,
81±77, 67±64 ± SEM, N=180) on average respectably and it was (112±108, 69±65,
Number of Survivals Per Life
Stage
47±44) ± SEM, N=180) on average respectably for the group on high carbohydrate diet.
160
140
120
100
Regular
80
High Carb
60
40
20
0
Larva
Pupa
Adult
Life Stages of Drosophila melanogaster
Figure 1:illustrates the average rate production for the life stages (larva, pupa and adult)
of the fruitless of the first generation with regular and high carbohydrate diet.
(pLarva=0.0876, pPupa=0.0641, pAdult = 0.0041 one tailed unpaired t-test)
The results from the second generation are shown in (Figure 2). On average the rate
production was higher for the group on the regular food diet than the group on high
carbohydrate diet. The rate production average for larva, pupa and adult for regular food
diet was (161±158, 96±92, 80±76 ± SEM, N=180) respectably and it was (101±98,
45±41, 26±23) ± SEM, N=180) respectably for the group on high carbohydrate diet.
Number of Survivals Per Life Stage
160
140
120
100
80
Regular
60
High Carb
40
20
0
Larva
Pupa
Adult
Life Stages of Drosophila melanogaster
Figure 2:illustrates the average rate production for the life stages (larva, pupa and adult)
of the fruitless of the second generation with regular and high carbohydrate diet.
(pLarva=0.00145, pPupa=3.53*10-6, pAdult = 1.03*10-08 one tailed unpaired t-test)
Discussion:
The average reproduction and survival rate of the fruit flies that had regular food source
was higher in different life stages (larva, pupa and adults) compared to the fruit flies that
had high carb sugar nutrients. The average rate of reproduction of the 2nd generation is
even lower than the first generation for the flies that had high carb nutrient. Upon further
scrutiny and running the one tail unpaired t-test with all p value for the first and second
generations were less than 0.05, which confirms there is a statistically significant
difference in the average reproduction and survival rate of the two subject fruit flies.
Thus, it can be concluded that the results support the hypothesis that fruit files
with regular food diet have greater reproduction and survival rate in different life stages
compared to the fruit flies with high carbohydrate food diet. As the Carbohydrate to
protein ratio decreases and protein becomes more available in a diet, reproduction is
activated and much of carbohydrate energy is diverted from somatic maintenance to fuel
demand of reproduction and building lipid reservation in eggs. (Fanson et al., 2009).
Based on the recent studies with Drosophila melanogaster species, as the dietary yeast to
sugar ratios decreases, the life span of the fruit flies increases. (Fanson et al., 2012).
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