The Polistes carnifex, commonly known as the executioner wasp, is known for its formidable sting. While often perceived as highly aggressive, their behavior, like many wasp species, is primarily defensive. Their notorious sting contributes to this perception, but unprovoked attacks on humans are uncommon. Their aggression is typically a response to perceived threats, especially when their nest is involved.
Understanding the Executioner Wasp
The executioner wasp (Polistes carnifex) is a large paper wasp, notable for its size, often reaching 1 to 1.2 inches (24-27 mm) in length. Their bodies are typically yellow with brown stripes, and they possess reddish-brown wings. This species is native to tropical and subtropical regions of Central and South America, including countries like Mexico, Paraguay, Argentina, Brazil, Nicaragua, and Costa Rica.
These wasps build small, open paper nests from chewed wood fibers. Nests are commonly found in sheltered locations such as under the eaves of buildings or suspended from tree branches. Unlike some other social wasps that form vast colonies, executioner wasps live in smaller eusocial groups, typically comprising a queen and around 4 to 13 individuals. They feed on nectar as adults and provision their larvae with chewed caterpillars and other insects.
Drivers of Aggression
The aggression exhibited by executioner wasps is predominantly a defensive behavior, particularly when they perceive a threat to their nest or larvae. Proximity to their nest, sudden movements, or vibrations can be interpreted as threats, prompting a defensive response. Their sting is a potent defense mechanism, capable of delivering neurotoxic venom.
Their sting is considered one of the most painful insect stings, with some descriptions ranking it at level four on the Schmidt pain index. The pain is often described as intense, burning, or searing, and can even cause localized tissue necrosis. This intense pain, which can last for days to a week, serves as a strong deterrent to potential predators. Compared to common wasps like yellow jackets, the executioner wasp’s sting is notably more severe.
Encountering Executioner Wasps
To minimize the risk of a sting, avoiding areas where executioner wasps nest is advisable. If you encounter an executioner wasp or its nest, it is important to remain calm and avoid sudden movements. Waving your arms or attempting to swat the wasp can provoke a defensive attack. Slowly and calmly moving away from the area is the recommended course of action.
Do not attempt to remove an executioner wasp nest yourself due to their defensive nature and the severity of their sting; instead, contact a professional pest management service experienced in handling wasps. If stung, immediate first aid involves washing the affected area with soap and water. Applying a cold compress can help reduce swelling and pain, and over-the-counter pain relievers like paracetamol or ibuprofen may be used. Antihistamines can also help alleviate itching and swelling. Seek immediate medical attention if you experience signs of a severe allergic reaction, such as difficulty breathing, widespread swelling, or dizziness.