Why might pheromone traps attract more insects than they actually trap?

Pheromone traps are designed to attract specific insects using chemical signals, or pheromones, that mimic the natural scents produced by those insects to find mates or food sources. The correct answer highlights a key aspect of the operation of these traps. While they may draw a significant number of insects towards them due to the compelling scent they emit, not all attracted insects will necessarily enter the trap or be captured.

Insects may land near the trap or engage with it but might fail to become ensnared due to various factors such as trap design, insect behavior, or environmental conditions. For instance, if insects are flying erratically or are cautious because of nearby activity or threats, they might be lured in, but not captured. This phenomenon contributes to the disparity between the number of insects attracted and the actual capture rate.

The other options do not capture the primary reason for the discrepancy between attraction and trapping effectively. For example, pheromone traps are specifically designed to attract certain species rather than repel them, and although they can be less effective in certain conditions (like at night), their primary function is not to attract insects at those times. Therefore, option C accurately describes a common scenario with pheromone traps in pest management.