BiomedicalSciencesresearchpaper (1)

Bean Beetles in Cultured Environments

Bean beetles location/ oviposition

Research paper

By Julien O’Neil

Biomedical Sciences

Greater Orlando Upward Bound Math/Science

CULTURED ENVIRONMENT/LOCATION/OVIPOSITION 1

Abstract This experiment is 3 different experiments in one the environment and its effects on the

beetle was one experiment. One environment was completely covered in vegetable oil while the

other environment was dry no oil was present. We hypothesized that the bean beetles wouldn’t

survive in the oily environment. We predicted that the beetles will survive in the oil absent

environment. Our Hypothesis was proving to be accurate but in our final test more beetles

survived in oily environment then in the two previous tests before that. The second Experiment

that was tested was the location of the beetle technically what bean it was attracted to more one

bean had oil the other wasn’t oiled. The hypothesis for this experiment was the bean beetles will

prefer a dry bean over a oily coated bean. The prediction that we came up with was if a bean is

coated in the oily substance, then the beetle would prefer a dry bean.


Introduction

The scientific name for bean beetles are Callosobruchus maculatus, which are

agricultural pest insects of Africa and Asia that presently range throughout the tropical and

subtropical world (Beck and Blumer 4). This species also is known as the southern cowpea

weevil. The larvae of this species feed and develop exclusively on the seed of legumes which

gives it the name bean beetle. The adults do not require food or water and spend their very short

life, mating and laying eggs on beans. Callosobruchus is one of the genera in the subfamily

Bruchinae (seed beetles) that is in the family Chrysomeloidae. This group is part of the order of

beetles, Coleoptera (Beck and Blumer 4).

The life cycle of a bean beetle is very short it’s about one to two weeks which is about 7

to 14 days. A bean beetle becomes fully matured 24 to 36 hours after it burrows out of the bean.

Once impregnated, adult females will lay fertilized eggs on the external surface of the bean

(such as mung beans, black eye peas, or adzuki beans). Individual eggs they are oval, clear,

shiny, and “glued” to the bean surface. The larva that hatches from the egg burrows from the

egg through the seed coat and into the bean without moving outside the protection of the egg.

Once the larva burrows into the bean, the remaining egg becomes white or mottled as it

fills with feces from the larva. The larva burrows and feeds on the bean endosperm and embryo,

undergoes a series of molts, and burrows to a position just underneath the seed coat prior to

pupation. A female adult can lay over a hundred eggs. Bean beetles experience two adult forms

(morphs), a sedentary (flightless) form and a dispersal (flying) form. Majority of the beetles lay

eggs on Black eyed beans ( refer to figure).


Figure 2 is displaying both male and female. The male Callosobruchus maculatus has a much

smaller abdominal and dorsal area than the female. On the left is a male, on the right is a female

(refer to figure 2) .

Methods/ Procedures

Experiment 1 cultured environments

The hypothesis of the first experiment conducted was that the bean beetles wouldn’t

survive in the oily environment. It predicted that the beetles will survive in the oil absent

environment. During this experiment there was three test, this experiment was entitled Cultured

Environments. Three petri dishes were oiled with vegetable oil while the other three petri dishes

were left with a dry environment. 35 mm dishes was used for every test, The bean beetles were

cultured in a 30°C incubator. The beans that were used for every test and experiment was black

eyed beans. Three beans were placed in each petri dish that’s twentyseven black eyed beans.

One male and female was placed in each petri dish with both environments. The very first thing

done in this experiment was to oil three petri dishes and get enough beans to put enough in each

dish. It was believed that the beetles wouldn’t survive because it possibly could suffocating

them. The chemicals within the vegetable oil could be very harmful to them.

As that task was completed next the beetles were taken from the 30°C incubator.

Now the sex of the bean beetles needed to be identify. This was done by using a

microscope, must check closely to avoid any errors in identifying the sex of the bean beetles.

Once that is done you must know take the beetles and start placing them in the proper dishes.

Now that those processes are complete you must place the beetle's back into the proper incubator


which is 30°C and then observe it later to take the data. This process was tested three times what

was looked at was the survival of the beetles in both cultured environments, both oily and

nonoily environments. We put about four drops of vegetable oil inside the petri dishes that were

labeled as the oily environment.

Experiment 2 Location of the beetle

The hypothesis of this experiment is The bean beetles would be located on a dry bean

instead of a oily coated bean. It was predicted that if a bean is coated with vegetable oil, then

the beetle would be located on a dry bean. In this experiment a new group of female

Callosobruchus maculatus. When selecting the beetles you must be very careful the littles bit

of pressure could crush them. There was one female in each petri dish 3 petri dishes in the total

with two beans. The size of the petri dishes was 35mm (refer to figure 3) which was used for

every test/trial. Within each dish there was two beans, one bean was coated with vegetable oil

while the other bean was dry not coated in oil.

Based off of the hypothesis that says the bean beetles would be located near a dry bean

when observed was a at the moment observation that's why it was checked multiple times to see

if the beetle was trying to avoid one bean instead of another. The females that were chosen were

matured and going through gestation. It was believed that the beetles would stay away from the

oily bean because vegetable oil would irritate them. In 15 minute intervals the beetles were

checked to see where their location was.


Experiment 3 Oviposition

In this experiment it used the same procedures as experiment two. The hypothesis for

this experiment is covering beans in vegetable oil will affect oviposition. The prediction of this

experiment is the bean beetles will only lay eggs on the dry beans. Female bean beetles were

taken and placed in petri dishes. One beetle to every petri dish, three dishes total, had to

determine the the sex of the beetle first then one of the beans had to be coated in vegetable oil.

The other bean was left uncoated what is being tested is if the female bean beetle is going to lay

her eggs on the oil coated bean or the dry bean. The bean beetle were cultured in a 30°C

incubator. When handling the beetles they must be handled very gently if not they can be killed

very easily. When taking the beetles out a very thin piece of paper would be able to handle the

with.

Results

Experiment 1 Survival in Cultured Environments

What was observed in this experiment that the cultured environments altered the survival

of the bean beetles. Even though we hypothesized bean beetles wouldn’t survive in the oily

environment. The prediction was that the beetles will survive in the oil absent environment.

This turned out to be true in all three trials that we did. The final trial however was very

different from the rest of the data.

For the first trial six out of six beetles died in the oily environment however, five out of six in

dry environment survived. For the second trial had the same exact outcome six out of six beetles

died in the oily environment however, five out of six in dry environment survived. For the third


experiment which had the biggest change that was completely unexpected 2 out of 6 beetles died

in the oily environment: 3 out of 6 in dry environment survived. Within the data taken we took

all the surviving and non surviving beetles in both cultured environment and averaged them and

got an average and a average percentage. The average number of survivor a dish in the dry

environment is 14. The average number of survivors in the oil is 0.4. The average percentage of

survivors in the dry environment is 75%, while the average percentage in the oily environment is

25%. (refer to figure 4 and 5).

Experiment 2 Location

The hypothesis of this experiment is The bean beetles would be located on a dry bean

instead of a oily coated bean. It was predicted that if a bean is coated with vegetable oil, then

the beetle would be located on a dry bean. In 20 minute intervals the beetles were checked to see

where their location was. The location of the beetles were checked six times, on three different

days. There was three different petri dishes that had one male and female, and it had two beans in

each dish, one bean oiled one bean not oiled. On the first day at 10:10 a.m. in all three petri

dishes beetles were located near the dry beans.

At the second time that it was checked it was the same exact result which was taken

10:30. At 10:50 in one dish the beetles died in the other two the beetles were located near the

oily beans. With all of the data taken from the three days and six different observations we took

all of it it and found the average percentages. The average of beetles that were located near the

dry beetles is 78%. The average percentage of beetles that were located near oily beans was 14%

(refer to figure 6).


Experiment 3 Oviposition

In this experiment it used the same procedures as experiment two. The hypothesis for

this experiment is covering beans in vegetable oil will affect oviposition. The prediction of this

experiment is the bean beetles will only lay eggs on the dry beans. Based on what was observed

during the three trials conducted with the three different replicase is that in replicate one the

female bean beetle laid 14 eggs on the dry bean, and zero eggs one the oily bean. In replicate 2

seven eggs on the dry bean and zero on the oily bean. In replicate 3 nine beetles were laid on the

dry beans and again zero beans were laid on the oily bean. During the second trial replicate one

the female beetle laid 10 eggs on the dry bean however the female in this trial test died while the

male was still alive again no eggs were laid on the oily beans. In replicate 2 both male and

female were alive, seven eggs laid on the dry bean again no eggs were laid on the oily bean. In

replicate 3 zero eggs were laid on the oily bean and 5 eggs were laid on the dry bean. For the

third test in replicate one it was observed that the amount of the 7 eggs laid on the dry beans, and

zero laid on the oily egg.(for the rest of the data averaged refer figure 7).

Conclusion

Based off of the data taken from experiment 1 entitled cultured environments we tested

our hypothesis of the bean beetles wouldn’t survive in the oily environment. It predicted that

the beetles will survive in the oil absent environment. With all of the data taken and how many

times we conducted this experiment there was just one unexpected shift in one of our three trials.

We were able to conclude that the bean beetles wouldn’t survive in an oily environment which


is what we predicted and hypothesised. We have come to believe that the beetles died in the

oily environment for more than one reason, one reason being that the oil could have suffocated

the beetles to death. but if you look the final trial that some beetles were able survived in that

environment.

Another thing we ultimately believe is that the oil could be very toxic to the beetle

therefore killing them. The average survivors a dish in the dry environment is 14. The average

survivors in the oil is 0.4. While the average percentage of survivors in the dry environment is

75%, while the average percentage in the oily environment is 25%. This information is accurate

because we did this experiment more than three times and the data recorded was the same.

Experiment number two was created to test the thought/understand process that we have come up

with.

Instead of coating the entire environment we went and coated one of the two beans in

the petri dishes. In experiment two we tested the hypothesis of this experiment is the bean

beetles would be located on a dry bean instead of a oily coated bean. It was predicted that if a

bean is coated with vegetable oil, then the beetle would be located on a dry bean. With the data

recorded it shows that the beetles are trying to stay away from the oily bean. I have enough data

to say this because like before i did enough trials for this experiment and consistently came out

with the same data. The location of the beetles would be near a dry bean every time i checked

them on 15 minute intervals for 1 hour and 30 minutes, that’s a total of 6 checks and on three

different trial days.

Experiment three the hypothesis for this experiment is covering beans in vegetable oil

will affect oviposition. The prediction of this experiment is the bean beetles will only lay eggs


on the dry beans. Based off of the data from the other two experiments we wanted to see if oil

coated beans and nonoily coated beans would affect oviposition. Which it did, as we observed

all replicates we looked to see where the beetles laid their eggs at then we have had to observe

how many eggs that is on each bean. Easily for us our hypothesis and prediction was

completely correct, the bean beetles completely left the oily beans alone no eggs were laid on

them in either trials taken down. Eggs were only laid on the dry noncoated beans. Proving that

since the beetles have a choice they will not lay eggs on the oily beans. However the beetles paid

no attention to the oily beans so i have been able to make another statement and have data that

could easily back me up, if there was only beans that were oiled the beetles would most likely

not lay their eggs on the beans and would ultimately die.

From analyzing the data we have this information could help farmers in so many ways

that means less use of pesticides that can possible be harmful to humans other animals and

insects. Some pesticides cost a great amount of money and using oil as a way to keep away the

beetles could save them so much money. If the oil is toxic to the beetles they will do what die

off or relocate to a new region saving the crops from pests. A pesticide a substance used for

destroying insects or other organisms harmful to cultivated plants or to animals. Pesticide use

can damage agricultural land by harming beneficial insect species, soil microorganisms, and

worms which naturally limit pest populations and maintain soil health; Weakening plant root

systems and immune systems; Reducing concentrations of essential plant nutrients in the soil

such nitrogen and phosphorous.

Think about a few less pesticides being used means less crops and animals possibly

being harmed. From the data collected from all three experiments we have observed that it is


difficult for the bean beetles to thrive in an oily environment. In the experiments the bean

beetles prefer dry beans over oily coated beans. With all of the information that i’ve gathered

with my group we can come to a complete conclusion that Callosobruchus maculatus in some

way doesn’t want to come in contact with anything with oily because it could be very harmful.

A cultured environment at 30°C and petri dishes coated in oil and not coated in oil lead to many

different outcomes. Oil should be used as a way to get rid of bean beetles.

I’ve learned so much in my research science class Dr. Handy didn’t just teach us about

bean beetles or conversions he taught us how to respond to life. He helped us think in a greater

aspect, he helped us think way outside the box. Dr. Handy opened us to a better understanding

about life. It was basically life science before biomedical sciences, when we were able to break

something down in a simple process it made everything else easier. The entire Biomedical

science group had constant help with editing our powerpoints, he asked us questions that he

believed would be asked, the questions were very challenging but it was preparing us for

greatness. In the end i feel like everything Dr. Handy did helped me in that presentation and in

life because he used life situations and related it to what was important to know at the time. Dr.

Handy also talked out current events to see how we think about things and he used that

information and improved our thinking process individually and in groups and i know everything

he said and taught us can help us in future cases, he also put in our minds that we would have the

best presentations because he would have challenged us already so we know how to deal with.

With everything that has happened i thank Dr. Handy because his simple metaphors and stories

gave us something to work forward to, a set goal


Work Cited

Beck, C. W., & Blumer, L. S. (2014). A handbook on bean beetles, callosobruchus maculatus.

National Science Foundation.


Appendix

Figure 1 shows eggs laid on the Black eyed beans.

Figure 2 is displaying both male and female. The maleCallosobruchus maculatushas a much smaller abdominal and dorsal area than the female. On the left is a female, on the right is a female.

Figure 3 is a 35 mm petri dish that is used throughout each experiment.

Average and average percentage figure 4 and 5


Figure 6 Average location of bean beetles


figure 7

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