The Tiger Bee Fly (Xenox tigrinus) is a large insect often mistaken for a stinging pest due to its striking appearance. It is actually a species of true fly belonging to the family Bombyliidae (bee flies), not a bee or a wasp. Despite its intimidating looks, the adult Tiger Bee Fly poses no threat to people or pets.
Identifying the Tiger Bee Fly
The appearance of the Tiger Bee Fly is an example of Batesian mimicry, where a harmless species evolves to look like a dangerous one to deter predators. Adults typically measure between 11 and 19 millimeters (0.43 to 0.75 inches) in length. Their black bodies are covered in fine, fuzzy hair, which gives them a bee-like plumpness.
A distinctive feature is the pair of transparent wings, which display an intricate, dark, mottled pattern often described as resembling tiger stripes. The abdomen is black and usually marked with two distinct white spots. Unlike a bee or wasp, which has two pairs of wings, the Tiger Bee Fly possesses only a single pair of wings. This size and coloration often lead to it being confused with the Eastern Carpenter Bee, its primary host, or even a large bumblebee.
Assessing the Risk to Humans
Despite its size and buzzing flight pattern, the Tiger Bee Fly is definitively harmless to humans. This species completely lacks the anatomical structure required to sting. As a fly, it does not possess a venom-injecting stinger found on bees and wasps.
Furthermore, its mouthparts are not designed for biting or drawing blood from mammals. The adult fly primarily uses its proboscis for sipping nectar from flowers. The intimidating resemblance to stinging insects is purely a defensive strategy to ward off birds and other predators.
The species is not known to be a vector for any diseases transmissible to humans. When a Tiger Bee Fly hovers near a person, it is not exhibiting aggression; it is often simply investigating its surroundings or searching for a mate or a host site. There is no risk of a bite, sting, or disease transmission.
Natural History and Lifecycle
The Tiger Bee Fly plays a specialized role in the ecosystem, acting as a parasitoid, particularly of the Eastern Carpenter Bee (Xylocopa virginica). The female fly seeks out the entrance holes of carpenter bee nests in wooden structures, such as decks or fences. She then deposits her fertilized eggs near the tunnel entrance.
Once hatched, the fly larva is highly mobile and navigates its way into the wooden gallery where the carpenter bee eggs and larvae reside. The fly larva then attaches itself to and consumes the carpenter bee larva, effectively controlling the population of the wood-boring pest. This natural process is why the Tiger Bee Fly is frequently observed hovering around wooden areas of homes. The adult flies sustain their energy by feeding on flower nectar, making them minor but beneficial pollinators.