The Lightning effect is a dominant gene that is found in the Energetic Branch.
What the lightning effect does is that it causes lightning to strike on the surface in or above the bee's territory.
Myth: The lightning centers on players unprotected by bee effects.
Fact: The small area that a Queen's territory affects makes the lightning strikes very tightly, making any players that are not protected from the effect very likely to be harmed by the effect.
Lightning Wiki Entry
Caution is to be used when breeding the Energetic Branch's bees; No important flammable objects nearby.
Link to the branch of the gene's natural host(s): http://extra-bees.wikia.com/wiki/Energetic_Branch
Sources: No better source than half an hour of personal testing.