Review Questions

Quiz

Question

Question: Which of the following are Bt proteins discovered that are toxic to CRW?

a. Cry 3Bb1

Incorrect: Refer to the ‘Handy Bt table guide’ linked in the lesson.

b. Cry34/35Ab1

Incorrect: Refer to the ‘Handy Bt table guide’ linked in the lesson.

c. Cry1Ab

Incorrect: Refer to the ‘Handy Bt table guide’ linked in the lesson.

d. All of the above because all Bt proteins are toxic to CRW to some degree.

Incorrect: Refer to the ‘Handy Bt table guide’ linked in the lesson.

e. a and b above

Correct: Yes, there are several Bt proteins identified with CRW toxicity, different Bts are toxic to other insect pests.

Looks Good! Correct: Yes, there are several Bt proteins identified with CRW toxicity, different Bts are toxic to other insect pests.

Question

Question: Based on what you learned about the field research conducted by Lance Meinke and his team, which statement is true?

a. The research approach is simple and not costly and has been used to test the response of hundreds of different populations of CRW to the rootworm Bts.

Incorrect: Watch the second video in this lesson again and think about the way the experiment was set up and conducted.

b. The research approach is labor intensive and costly and provides information on the response of just one CRW population.

Correct: Yes, the research is difficult and so is only conducted in a single or in limited locations.

c. The research only examines the response of the CRW population during a few days of the growing season.

Incorrect: Watch the second video in this lesson again and think about the way the experiment was set up and conducted.

Looks Good! Correct: Yes, the research is difficult and so is only conducted in a single or in limited locations.

Question

Question: Which life cycle stage of the CRW was collected and counted in this study and how was it collected?

a. Corn roots from a section of the plot were excavated every week and the number of larvae living near or on the roots was counted.

Incorrect: Refer to Research Part 2 of this lesson.

b. Corn roots from a section of the plot were excavated during the peak feeding week determined in previous studies and the number of larvae living near or on the roots was counted.

Incorrect: Refer to Research Part 2 of this lesson.

c. Adult beetles found in tents with no floors were sucked up every morning for about 60 days.

Correct: Yes, counting adults revealed success of the larvae living on the corn in each plot.

d. Adult male beetles were trapped in containers and counted every day for a week starting in early July.

Correct: Yes, counting adults revealed success of the larvae living on the corn in each plot.

Looks Good! Correct: Yes, counting adults revealed success of the larvae living on the corn in each plot.

Question

Question: When did the rootworm Bt corn plants have the biggest difference compared with the non-Bt control with insecticide and the non-Bt with no insecticide?

a. In late July when the largest number of adults in the population were emerging.

Correct: The peak emergence of CRW adults was later in the Bt plots and much lower than the numbers counted in the non-BT control that lacked an insecticide treatment.

b. Very early in the growing season.

Incorrect: Examine Figure 5 again.

c. Later in the growing season.

Incorrect: Examine Figure 5 again.

d. There was never a big difference between the number of CRW collected between the Bt plots and the controls in this experiment.

Incorrect: Examine Figure 5 again.

Looks Good! Correct: The peak emergence of CRW adults was later in the Bt plots and much lower than the numbers counted in the non-BT control that lacked an insecticide treatment.

Question

Question: Based on figure 5, what mating is likely to happen?

a. A non-random mating based on the ability to become an adult in a Bt plot.

Correct: Yes, the delayed emergence of CRW on the Bt means that there may not be as many CRW available to mate with that had not experienced Bt selection pressure. This is non-random mating.

b. Random mating between CRW adults that emerge in non-Bt and those that emerge on Bt plants in the same field.

Incorrect: Adults will be looking for mates. The goal is for adults that emerged from Bt fields to mate with those that have not experienced that selection pressure, to prevent the generation of offspring from two resistant parents.

c. The data does not allow us to think about mating of CRW.

Looks Good! Correct: Yes, the delayed emergence of CRW on the Bt means that there may not be as many CRW available to mate with that had not experienced Bt selection pressure. This is non-random mating.

Question

Question: Which of the following choices was a reason Refuge in a Bag (RIB) developed as an alternative to refuge planted by the farmer in a block?

a. Companies were not developing any non-Bt hybrids so refuge in a block no longer was an option.

Incorrect: Reconsider your answer choices.

b. Planting a refuge of a non-Bt hybrid imposes some time restraints on a farmer during their busy planting season and thus some farmers might fail to plant the refuge.

Correct: By planting Refuge in a Bag Bt corn, the farmer is providing a refuge and opportunity for CRW to grow, survive, and maintain susceptibility in the population.

c. Research like that described in this lesson, demonstrated that RIB was going to impose less selection pressure on the CRW population AND have less CRW damage overall in the field.

Incorrect: Reconsider your answer choices.

d. It was demonstrated that the CRW adults that emerge in the block refuge only mate with each other and fail to mate with adults that survive living on Bt plants.

Incorrect: Reconsider your answer choices.

Looks Good! Correct: By planting Refuge in a Bag Bt corn, the farmer is providing a refuge and opportunity for CRW to grow, survive, and maintain susceptibility in the population.

Question

Question: An entomologist measures the amount of rootworm damage to non-Bt corn plants in a ‘refuge in a block’ field compared to a ‘refuge in a bag’ field. The non-Bt refuge plants have LESS damage on average in the ‘refuge in the bag’ field than in the ‘refuge in a block’ field. Which choice below provides the best explanation for this contrasting observation?

a. The Bt plants in the refuge in a bag field are making a more toxic level of the Bt protein than the same hybrid of plants would be making when planted in a block.

Incorrect: Reconsider your choices.

b. The Bt protein must be getting transferred from the Bt plants to their neighboring non-Bt plants in the refuge in a bag field and this causes the CRW to do less feeding.

Incorrect: Reconsider your choices.

c. The CRW larvae can move as they feed and grow. Some will feed for a while when they are small on non-Bt plants but have the option of moving to neighboring Bt plants to feed. They no longer feed on and damage the refuge (non-Bt plants)

Correct: Yes, the observation of less damage also corresponds with an observation of more damage to the neighboring Bt plants in the RIB field. So movement of the CRW larvae as they grow is a valid explanation.

d. The CRW larvae are more restricted in the refuge in a bag field. They must stay near and continue to feed on the non-Bt refuge plants and thus consume more root mass on these plants.

Incorrect: Reconsider your choices.

Looks Good! Correct: Yes, the observation of less damage also corresponds with an observation of more damage to the neighboring Bt plants in the RIB field. So movement of the CRW larvae as they grow is a valid explanation.