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The beet caterpillar is an insect pest of the tomato plant - VCE - SSCE Biology - Question 4 - 2009 - Paper 1
Question 4
The beet caterpillar is an insect pest of the tomato plant. When a beet caterpillar starts to eat a tomato plant, the plant responds by producing a chemical known as... show full transcript
Worked Solution & Example Answer:The beet caterpillar is an insect pest of the tomato plant - VCE - SSCE Biology - Question 4 - 2009 - Paper 1
Step 1
i. Outline an experiment you would carry out to test this hypothesis.
Answer
To test the hypothesis that the odours emitted by tomato plants affected by beet caterpillars attract wasps, we could conduct the following experiment:
Experimental Setup:
- Selection of Subjects: Choose a controlled environment where both caterpillar-infested and healthy tomato plants can be observed. Ensure that these plants are of similar age and size for consistency.
- Release of Wasps: Introduce a fixed number of wasps into this environment.
- Observation Period: Allow a set period (e.g., 1 hour) for the wasps to interact with the plants.
- Data Collection: Record the number of wasps that are attracted to each type of plant (the infested vs. non-infected) during the observation period.
Control Measures:
- Ensure that environmental factors such as light, temperature, and humidity are kept constant.
- Use masking to prevent any outside influences or odors from affecting the results.
This would allow us to determine if the wasps preferentially seek out the plants that are infested by caterpillars.
Step 2
ii. Describe the results that would support the hypothesis.
Answer
Results that would support the hypothesis would show a significantly higher number of wasps attracted to the tomato plants that are infested by beet caterpillars compared to the healthy plants.
For instance:
- Quantitative Evidence: If 70% of the wasps are observed near the infested plants while only 30% are near healthy plants, this would suggest a clear preference, supporting the hypothesis that the odours from damaged plants attract wasps.
- Behavioral Response: Additionally, if the wasps exhibit more frequent landing or hovering behavior around infested plants, it would further validate that they are attracted to the specific odours released by jasmonic acid.
Step 3
b. Explain why it could be an advantage to the plant to produce jasmonic acid when its leaves are being eaten by caterpillars.
Answer
Producing jasmonic acid when its leaves are being eaten by caterpillars offers several advantages to the tomato plant:
1. Attraction of Natural Predators
The emission of jasmonic acid can attract wasps, which are natural predators of the caterpillars. By luring these wasps, the plant can increase the likelihood of predation on the pests, reducing damage and potential loss of leaves.
2. Induction of Defense Mechanisms
Jasmonic acid plays a critical role in activating the plant's internal defense mechanisms, such as the production of secondary metabolites that deter herbivores from feeding. These compounds can be toxic or unpalatable to caterpillars, thus protecting the plant from extensive damage.
3. Signaling Other Plants
The volatile compounds released, including jasmonic acid, can serve as a warning signal to neighboring plants, prompting them to activate their own defense responses even before they are attacked. This communal response can enhance the resilience of the local plant population against pest attacks.
Overall, the produced jasmonic acid promotes survival by not only reducing herbivore damage but also enhancing the plant's overall defense strategy.