Kakugo (Ready to Attack) or Kakugo RNA is a Picorna-like virus, which is most commonly found in the brains of worker bees. The Kakugo virus, when resident in a bee's brain, can contribute to aggressive behaviors such as are preeminent during a bee's guard phase in their life cycle. Kakugo is the first virus to have been found to cause aggressive behavior, although because the virus was only recently discovered to have such effects, research into the matter is limited.
Kakugo RNA encodes a protein of 2,893 amino acid residues that shares structural features and sequence similarities with various picorna-like virus polyproteins, especially those from sacbrood virus, which infects honeybees. The Kakugo protein contains several domains that correspond to the virion protein, helicase, protease, and RNA-dependent RNA polymerase domains of various picorna-like virus polyproteins.