A bumblebee can sense electric fields. The most likely mechanism underlying this sensitivity is motion of hairs on the bee’s body; the hairs bend in response to an electric field. Support for this mechanism as the source of the sensitivity is the fact that putting an electric charge on a bee (as occurs when a bee flies through the air) dramat- ically increases electric field sensitivity. Explain why adding charge to a bee would cause hairs on the bee’s body to bend more in response to a field.

The bee's hairs carry electrical charges.
The electrical field around the bee exerts a force on the bee's hair, causing them to bend.
The bee senses the electrical field by sensing the bend in its hairs.

Consider the bee's hair as a point charge. The force [tex]\vec{F}[/tex] between an electrical field and that point charge would be equal to

[tex]\vec{F} = q \cdot \vec{E}[/tex].

the strength and direction of the electrical field, [tex]\vec{E}[/tex], and
the size (and sign) of the charge on the object. [tex]q[/tex].

In this equation, the size of the electrostatic force [tex]F[/tex] is proportional to the size of [tex]q[/tex], the charge on the bee. Adding charge to the bee's hair would increase the size [tex]q[/tex]. Even if the size of the field stayed the same, there would be an increase the size of [tex]F[/tex].

The hairs would now bend more since the force on them has become stronger. That means the bee would become more sensible to the electrical field.