Why are some baits designed to kill pests slowly?

The design of some baits to kill pests slowly is primarily to enhance the effectiveness of the pesticide across an entire insect colony. When a bait acts slowly, it allows the targeted pest to return to its colony after ingestion. This enables the slow-acting poison to be shared among other members of the colony, as affected pests can transfer the bait to others through grooming or feeding behaviors. In this way, the bait not only eliminates the individual that consumed it, but it can subsequently lead to a wider impact on the entire population.

This gradual approach takes advantage of social behaviors in certain pest species, ensuring that the active ingredient is disseminated more effectively than if it acted rapidly. The other options do not align with the primary reasons for using slow-acting baits in pest control strategies. For instance, increasing the volume of pesticide or ensuring only small amounts are consumed do not contribute to the goal of colony-wide control, and avoiding detection by larger animals may not be a focus in the design of such baits.