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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 jasmonic acid odours attract wasps, an experiment can be designed as follows:
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Preparation: Identify two groups of tomato plants: one group will be treated with jasmonic acid and the other group will remain untreated. Ensure that both groups are of similar size and health.
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Attractiveness Test: Introduce beet caterpillars to the leaves of the treated plants to elicit jasmonic acid production. Monitor the second group without caterpillar exposure.
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Observation Period: Over a fixed period, such as 24 hours, observe the number of wasps attracted to each group of plants. This can be done by placing sticky traps around each group.
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Data Collection: Record the number of wasps that visit both the treated and untreated plants.
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Analysis: Compare the number of wasps attracted to each plant group using statistical analysis to determine if there is a significant difference.
Step 2
ii. Describe the results that would support the hypothesis.
Answer
Results that would support the hypothesis would show that a significantly higher number of wasps are attracted to the plants treated with jasmonic acid compared to the untreated plants. This could be quantified by the data collected from the sticky traps, indicating a clear preference for the jasmonic acid-emitting plants. Additionally, if the wasps are seen actively feeding on the nectar or laying eggs near the treated plants, this behavior would further support the hypothesis.
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 provides multiple advantages to the plant:
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Attracting Predators: Jasmonic acid helps attract host-specific wasps and other predators that can directly reduce the caterpillar population, thus minimizing damage to the plant.
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Enhanced Defense: The production of jasmonic acid can also trigger other defensive mechanisms in the plant, such as the synthesis of toxic compounds or physical barriers to deter herbivores.
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Signal for Systemic Response: Jasmonic acid acts as a signaling molecule, prompting the rest of the plant to enhance its defense response, preparing it for further herbivore attacks. This can lead to improved overall resilience against pests.