My only misgiving stems from an incident several years ago when I found a caterpillar and tossed it into the pond as a treat for my koi. The koi that ate it (a beautiful 24 incher) was found floating on the surface the next morning...dead! I later identified the caterpillar as a Pipevine Swallowtail, which is poisonous to animals if eaten. Now I don't expect my bug zapper to zap any caterpillars but I'm wondering whether the Pipevine Swallowtail butterfly might prove poisonous if zapped, along with any other potentially poisonous insects.

Any thoughts?

I'm also trully sorry about your Koi whatever happened to it.

Montalvo, Wiki states in it's first paragraph on the Pipevine Swallowtail that the butterfly is absolutely poisonous due to the diet it had as a Caterpillar. I had no idea! Thanks for the warning even though I doubt I have any in this area. I wonder what other surprises Mother Nature has like this.

" The Pipevine Swallowtail (Battus philenor)[1][2] is a swallowtail butterfly found in North and Central America. The butterflies are black with iridescent blue hind wings. They are found in many different habitats, but are most commonly found in forests.[3] The black or red caterpillars feed on Aristolochia species, making them poisonous as both larvae and adults, while the adults feed on the nectar of a variety of flowers."

It is doubtful the large butterfly could manage to get inside the surrounding grid to get zapped. I remember being very concerned about a Luna Moth that clung to a Zapper all night and the next day. It flew away only after I unplugged the Zapper. Zappers don't usually attract much during the day and for mosquitoes you have to add on a bait packet.

Another thing to consider is that butterflies don't fly at night the way moths do. Or am I mistaken? I've never seen one or heard of one that does.

I hadn't thought about the fact that the grid on the zapper would make it difficult, if not impossible, for the butterflies to get near the zapping grid. I'm feeling much relieved so I'm going to hang it up. We're leaving Sunday for an African safari (24 days) and while I have an automatic feeder, I'll feel more comfortable with the zapper as a back-up. The auto-feeder has malfunctioned in the past and that's a long time for my koi to go without food, especially right before winter sets in.