Toxic Butterflies in Florida

We're often asked by guests if Monarch Butterflies (Danaus plexippus) are toxic, and our answer is: Only if you eat them. This gets us a lot of scrunched up, disgusted looking faces, but it is the truth. Several species of Florida butterflies consume plants that contain compounds that render them distasteful or toxic to humans and other predators.

Monarch and Queen Butterfly

Monarchs and Queen butterflies (Danaus gilippus) feed on plants in the genus Asclepias which contains cardiac glycosides that are poisonous to humans and other species that might consider eating a Monarch. The cardenolides (C₂₃H₃₄O₂) found in Milkweed are similar to compounds found in other toxic plants like Digitalis and Oleander.

Cardenolide

Viceroy Butterfly

This butterfly if often listed as a tasty mimic that models itself after the Monarch butterfly, which is known to be distasteful to predators. But it turns out the Viceroy is actually a Mullarian mimic, meaning that it looks like another toxic species and is also toxic itself. Viceroys feed on Willows (Salix) which contain Salicylic acid (C₆H₄(OH)COOH). Salicylic acid is handy to externally treat acne and dandruff, but the taste is incredibly bitter and astringent.

Salicylic acid

Pipevine and Polydamas Swallowtails

Pipevine (Battus philenor) and Polydamas Swallowtails (Battus polydamas) both feed on plants in the Pipevine (Aristolochia) family. Pipevines (also known as birthworts) contain aristolic acids (C₁₇H₁₁NO₇) that are a family of carcinogenic, mutagenic, and nephrotoxic compounds. Caterpillars that consume these plants can sequester the aristolic acids in their bodies and convert those acids to bitter tasting terpenes.

The FDA has released a strong warning on the consumption of anything containing aristolic acid as it has been linked to serious kidney damage and renal failure.

Aristolic acid

Atala Butterfly

Atala butterflies host on Coontie, a plant that is eventually edible is properly prepared so that all of the toxins in the plant are removed. Cycasin (C₈H₁₆N₂O₇)is a phytotoxin found in cycads, like Coontie. The chemical is retained in the body of the adult butterfly, thus making them toxic.

Cycasin

Learn more:

• Interactions with Milkweed (University of Minnesota)
• History of Salicylic Acid
• Herbal Medicine and Aristolochic Acid Nephropathy (Science Based Medicine)
• Study shows butterfly wings contain same toxin as sea snail (Phys Org)

To be very, very clear: we do not endorse the consumption of butterflies for purposes of scientific discovery on chemical loads that would prove toxic to humans. So please, don't eat the butterflies. Thanks!