Mating and oviposition occur around August. Young larvae hatch in fall and immediately search out grasshopper eggs to consume. Larvae undergo a dramatic physical change before overwintering, becoming more grub-like in appearance. After 6 instars of development, larvae become a 7th instar pseudo-pupa for overwintering. Though they are voracious feeders, blister beetles are of major concern due to their toxicity to livestock.
Blister beetles produce the highly toxic chemical cantharidin.
This poison is highly stable, and persists even after a beetle is killed. So beetles crushed during the harvesting process are still toxic to livestock. Horses are particularly sensitive to cantharidin poisoning. Cantharidin poisoning effects the urogenital and gastrointestinal systems. Symptoms include colic, abdominal pain, depression and anorexia Pollakiuria and frequent urination.