Associate Certified Entomologist (ACE) Practice Exam

Which of the following is a characteristic effect of phenylpyrazoles?

1. Immediate paralysis of insects

2. Slow action and hyperexcitation

3. Rapid lethality in humans

4. Stimulation of insect feeding

The correct answer is: Slow action and hyperexcitation

Phenylpyrazoles are a class of insecticides known for their unique mode of action that primarily affects the central nervous system of insects. They work by interfering with the transmission of signals between nerve cells, specifically by blocking certain neurotransmitter pathways. This disruption leads to hyperexcitation in insects, characterized by increased neural activity, which can result in prolonged spasms and ultimately death. The slow action associated with phenylpyrazoles means that the effects are not immediate; insects may exhibit symptoms over a period of time rather than instant paralysis. This is an important distinction because while other insecticides might show immediate results, phenylpyrazoles may take longer to cause the observable effects, allowing them to be effective over a broader time frame. The other options present characteristics that are either less relevant or incorrect regarding the action of phenylpyrazoles. Immediate paralysis does not accurately describe the effect since phenylpyrazoles typically result in a gradual onset of symptoms associated with hyperexcitation. Rapid lethality in humans is not relevant to this class of insecticides, as they are primarily designed for safe use around humans while effectively controlling pests. Lastly, stimulation of insect feeding does not occur with phenylpyrazoles, as their action generally leads to