Critical Reasoning (CR) | European honeybees have evolved sophisticated defense mechanisms again

European honeybees have evolved sophisticated defense mechanisms against predators that raid their hives. For example, when a raiding wasp is detected at the entrance to the hive, chemical signals are released by the detecting bees which cause other bees to swarm around and sting the intruder. This makes it difficult to understand why when a sparrow, which sometimes eats bees, is detected just outside the hive, no swarm-inducing chemical signal is produced.

Which of the following, if true, contributes
...

---