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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
Outline an experiment you would carry out to test this hypothesis.
Answer
To test the hypothesis that the odours produced by jasmonic acid attract wasps, the following experiment can be conducted:
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Selection of Plants: Use two groups of tomato plants, one group that has been infested with beet caterpillars and produces jasmonic acid, and another group that is healthy and not infested.
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Controlled Environment: Place both groups of plants in a controlled environment where factors like light, humidity, and temperature are constant to ensure that any observed effect is due solely to the presence of jasmonic acid.
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Attraction of Wasps: Monitor both groups for a set period (e.g., one week) and count the number of wasps that visit each group of plants. Ensure that the experiment is conducted at the same time each day to reduce variability in wasp activity.
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Analysis: Compare the number of wasps attracted to the infested plants versus the healthy plants. If more wasps are attracted to the infested plants, it would support the hypothesis that jasmonic acid and its odours attract them.
Step 2
Describe the results that would support the hypothesis.
Answer
Results that would support the hypothesis include:
- A statistically significant higher number of wasps visiting the tomato plants infested with beet caterpillars (and thus emitting jasmonic acid) compared to the control group of healthy, non-infested plants.
- Observational data stating that wasps show prolonged attraction or feeding behavior on the odours emitted from the infested plants, indicating that they are using these odours for orientation and that these may lead to potential control of the caterpillar population.
Step 3
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 leaves are being eaten by caterpillars provides several advantages to the plant:
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Attracting Natural Predators: Jasmonic acid can attract wasps that are natural predators of caterpillars. By luring in these wasps, the plant may reduce the caterpillar population, helping it recover from pest damage.
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Defense Mechanism: The presence of jasmonic acid can trigger defensive responses in the plant, such as the production of toxic compounds or repellents that deter further herbivory, effectively protecting its remaining leaves.
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Signal for Stress Response: Jasmonic acid acts as a signaling molecule that helps the plant activate various defense mechanisms, enhancing its overall resilience to pest attacks and allowing it to prioritize energy towards survival rather than growth.