Home » Bean » Callosobruchus Maculatus

Callosobruchus Maculatus

Callosobruchus maculatus is viewed as an economically relevant pest for multiple pulses, including grains such as lentils, chickpeas, and cowpeas, black-eyed beans, or Vigna unguiculata. These grains serve as primary sources of protein those who live in tropical and subtropical Asia and Africa, and when C. maculatus lay eggs into grains, the grains can no longer be eaten or replanted (Owolabi et al. , 2014), leading to quantitative and qualitative losses once the larvae insert eggs and droppings in the Vigna unguiculata (Torres et al. 2016 )

These larvae usually lay eggs on the surface of the beans or seeds field before or around the time of their harvest, which means that the eggs remain in the seed stores, where the eggs and total population are able to grow rapidly (K. Kebe et al. ). What allows the total population to grow so rapidly and infest stored grain is the life cycle of the C. maculatus; polyphenism, or the production of more than one adult morphs as a response to environmental changes, plays a crucial role during the life cycle.

C. aculatus have a flightless, sedentary morph that is considered “normal” and a flight or active morph. The adults of flight morph are not as fertile as those of the normal morph but lay eggs on developing pods. Once the infested beans are collected and stored, the adults of the flightless morph appear. Because of conditions such as like larval densities, abundance of food, wet environments, and lower temperatures, the sedentary morph develops easily and sexually reproduces rapidly until generations later the active morph emerges.

Since they are sexually active, they multiply rapidly up to 4–5 generations and after higher larval densities or due to genetic predispositions, adults of the flight morph begin to emerge. Such traits enable the C. maculatus to become serious threats to the grains (“Botanicals as Eco Friendly,” 2015,). While Fumigation was once the primary method used by farmers to control the threat of Callosobruchus maculatus, the most frequently used chemical, methyl bromide, was officially banned in 2015 since it worsened ozone depletion in the atmosphere.

Although other chemicals could be substituted, the cost and effectiveness often varies as a result of pesticide resistance (Alibabaie & Safaralizadeh). Nonetheless, the options for such chemical pesticides are also limited due to the strict regulations regarding the use of synthetic insecticides on or near food products. (Manal, Lobna, & Rashwan). Thus, the need for alternatives to mainstream pest control is quite pressing. In reality, people have been using different materials as pest control against Callosobruchus maculatus for centuries. Ancient Egyptians in 1000 B. C. for instance, used ash dust as pest control for their stores of grain (M. Hafez, Nadia Z. Dimetry, and M. H. Abbass).

More recently, essential oils have been considered effective pest control methods since they are comprised of volatile compounds and are not harmful to most mammals (G. K Ketoh et al. ). While the effectiveness of essential oils has been tested, the effectiveness of sunflower oil specifically is uncertain and thus needs to be tested. The goals of this experiment are to determine whether sunflower seed oil will be effective in preventing the C. maculatus from laying eggs on the Vigna unguiculata.

Based on the success of other essential oils, if the Vigna unguiculata are covered with concentrations of sunflower oil, then the C. maculatus will not be able to lay as many eggs on the beans as they would in the absence of sunflower oil. For the purpose of testing this hypothesis, the independent variable is the presence of sunflower oil, whereas the dependent variable is the number of eggs found on the beans after a period of time. The controlled variables include the temperature at which the C. maculatus are stored, the number of Vigna unguiculata per petri dish, and the level of light to which the petri dishes are subjected.

For this experimental design, the predictions are as follows: If the sunflower oil reduces the ability to lay eggs, there will not be as many eggs in the petri dish with sunflower oil. In summary, this experiment found that the quadrants of the petri dish containing the sunflower oil overall contained fewer eggs than those quadrants without oil. 1. Materials and Methods The Callosobruchus maculatus for this experiment were obtained from Bean Beetle cultures, item 144180, from Carolina Biological Supply Company.

Five female C. maculatus and five male C. aculatus were taken from the Bean Beetle Cultures and added to three separate petri dishes. Next, the black-eyed beans for the experiment, Vigna unguiculata, which were obtained from Signature Kitchens of Better Living Brands, LLC, were counted and eventually added to the dishes. Some of the beans had already been treated with different concentrations of sunflower oil from Expeller Pressed Spectrum Organic Sunflower Oil from The Hain Celestial Group, INC. To differentiate which parts of the dishes contained which concentration of oil, they were labeled with four separate quadrants: A, B, C, and D.

In each dish, quadrant A was filled with only 10 regular Vigna unguiculata that were not covered with any oil. Quadrant B was filled with 10 Vigna unguiculata covered with low concentrations, five milliliters per one kilogram, of the sunflower oil. Quadrant C, one of the experimental controls, was filled with no Vigna unguiculata. Quadrant D was filled with 10 Vigna unguiculata covered with high concentrations, ten milliliters per one kilogram, of sunflower oil. The petri dishes were then sealed and left out at room temperature for one week to allow the female C. aculatus to produce the eggs.

This experiment included both a positive and negative control. Quadrant A, which contained regular Vigna unguiculata was the positive control because it was expected that the C. maculatus would lay eggs upon them. The negative control in the experiment was quadrant C, in which there were no Vigna unguiculata, because it was expected that no eggs would be laid in this quadrant. These were included as controls because they would allow for a better comparison of the data form the quadrants containing oil.

Data was collected one week later. To collect the data, dissecting microscopes were used to inspect each bean for eggs. The beans were examined thoroughly under the microscope, and the total number of eggs per bean per quadrant was counted and recorded. Once the data was compiled for the whole class, it was then averaged and analyzed for error by standard deviation. 2. Results Each group’s results showed consistent patterns. Overall, the quadrants that contained sunflower oil contained the fewest number of eggs.

For every group except group 2, quadrant A, which contained only the Vigna unguiculata, contained the highest number of eggs. Quadrant B contained less eggs than quadrant A but contained more eggs than quadrant D. Consistently, each quadrant C for all groups had no eggs. As can be seen from Figures 1 and 2, Group 4 consistently found the most eggs per quadrant, with an average of 34. 33 eggs for quadrant A, 30. 67 eggs for quadrant B, 0 eggs for C, and 27. 0 eggs for quadrant D. Comparatively, the other three groups had markedly less eggs.

Figure 2 also demonstrates the calculated error in the data; the standard deviation for each group varied, but groups 1 and 2 had the lowest values for the standard deviation, whereas group 4 also had the highest values for standard deviation. As Figure 3 demonstrates, the class average for the number of eggs in quadrant A was approximately 17, and the average for the number of eggs in quadrant B was 16, which means that the only difference between the beans treated with low concentration of oil and untreated beans was a factor of one.

However, Figure 2 also demonstrates the much more exaggerated difference between quadrants A and D; whereas the average for quadrant A was approximately 17, the average for quadrant D was approximately 13. In such a small sample size, such a difference is significant. 3. Discussion This experiment found that despite application of oil to some quadrants, the C. maculatus were still able to lay eggs, as can be seen in Figure 3. The quadrants with no oil contained the highest average number of eggs and that the quadrants containing high and low concentrations of oil contained the lowest average number of eggs.

Quadrant C, however, contained no eggs for any of the groups because there were no Vigna unguiculata upon which the C. maculatus could lay any eggs. The results of this experiment support the hypothesis because the quadrants with the oil contained significantly fewer eggs than the quadrants with no oil. Referring to Figures 1 and 2, the graphs clearly demonstrate the gap between quadrant A and D, 17 eggs compared to 13 eggs. The gap indicates that the presence of sunflower oil had an impact on the ability of C. Maculatus to lay eggs.

However, when comparing the results of quadrants A and B, it becomes clear that there was no significant difference between the Vigna unguiculata with low concentration of oil and the Vigna unguiculata with no oil. Figure 3 demonstrates, while quadrant D had the most drastic difference, with a class average of approximately 13 eggs compared to quadrant A’s 17 eggs, quadrant B contained an average of 16. Thus, the low concentrations of oil did not have a drastic impact on the ability of C. maculatus to lay eggs.

The significance of these findings is that sunflower oil can also be considered a deterrent for the reproduction and survival of C. maculatus, but in high concentrations. And while the difference between the average number of eggs for quadrants A and D is only 4, in such a small sample size it is difficult to determine whether such a difference is truly significant or not; additionally, when the standard deviation (Tables 1, 1. 1, and 2) for both the individual groups and the class averages, the accuracy of the results becomes even more questionable.

Yet in one study of the residual effects of essential oils on C. aculatus, researchers noted that since low concentrations of oils could not penetrate fourth-instar, larvae and pupae inside the seeds, high concentrations of oil were needed to effectively ward off the C. maculatus (Ketoh et al. ) The results in this experiment were also somewhat comparable to the results of one study in which three different vegetable oils including sunflower oil reduced the ability of female C. maculatus from laying eggs on treated cowpea beans.

In that study, the recorded reduction ranged from 88. 82- 98. 49; 80. 31- 98. 58; and 86. 96- 98. 3% for corn oil, sunflower oil and sesame oil (Manal, Lobna, & Rashwan. ). However, in this experiment, the differences between the number of eggs on quadrant D and quadrant A were not quite that stark. Ultimately, while according to the results of the experiment the hypothesis was not entirely supported, it was not falsified because overall there was a reduction in the number of eggs produced by the females in quadrants that had been treated with oil. While the effectiveness of sunflower oil as a pest control in general remains unclear, its effectiveness as a deterrent for oviposition is evident.

Cite This Work

To export a reference to this essay please select a referencing style below:

Reference Copied to Clipboard.
Reference Copied to Clipboard.
Reference Copied to Clipboard.
Reference Copied to Clipboard.