BRISBANE, Australia—Every week, workers at one of Australia’s major airports spend hours searching the tarmac and terminals for a security threat that could bring down an airplane.

The inspectors at Brisbane Airport, in Australia’s third biggest city, are hunting for the keyhole wasp, an introduced species that builds nests in Pitot tubes—a crucial instrument on the fuselage that tells pilots how fast they are flying. The wasps, which build nests out of mud, can block a tube in as little as 20 minutes. They are smaller than similar native species and have distinctive rings on their bodies.