Blister beetle

Blister beetles are beetles in the family Meloidae, named for their ability to produce cantharidin, a defensive chemical that can cause skin blistering.

Blister beetles are beetles in the family Meloidae, named for their ability to produce cantharidin, a defensive chemical that can cause skin blistering. About 2,500 species are known worldwide, and adults are typically plant-feeders while larvae often feed on grasshopper eggs.

Taxonomy and name

Blister beetles belong to the beetle family Meloidae in the order Coleoptera. The common name refers to the skin reaction that can occur after contact with their cantharidin-containing body fluids.

Biology and life cycle

Adults are generally plant-feeding insects, while larvae of many species develop as predators or parasites in association with grasshopper eggs. This makes the group ecologically mixed, with both beneficial and damaging roles depending on life stage.

Defence and human impact

Blister beetles produce cantharidin as a defence against predators. Contact with crushed beetles can cause painful blistering, and ingestion of contaminated hay can be toxic to livestock, especially horses.

Distribution and diversity

Blister beetles occur worldwide, with roughly 2,500 described species and more than 400 reported in North America north of Mexico. Species differ in size, colour, and host plants, including striped, black, grey, and metallic forms. In Canada, they are found in prairie regions where some species can defoliate trees, shrubs, and garden plants, and Canadian agricultural guidance notes their importance in hay contamination risk for livestock.