Asian Lady Beetles are predators of aphids. In years when aphid populations are high, the population of Asian Lady Beetles increases. Asian Lady Beetles often overwinter in human structures. In years of high Lady Beetle Populations, the numbers present inside homes increase generating calls from concerned homeowners. Occasionally they will bite, but generally will not puncture human skin and do not seek to bite humans as do mosquitos and bed bugs.
When disturbed, Lady Beetles can reflex bleed and emit a foul smelling liquid. Reflex bleeding is an anti-predator defense. The foul odor and aposematic coloration send a warning to predators that learn to avoid the beetles.
Some predators fail to get the message. There are several reports of dogs that ingest lady beetles. What could go wrong? Instead of being swallowed, lady beetles can manage to cling to the roof of a dog’s mouth. Beetles clinging to the oral mucosa reflex bleed. The chemicals in the hemolymph are toxic and damage the tissue in the dog’s mouth. Dogs with a mouthful of lady beetles will drool excessively in an attempt to dislodge the beetles. However, drooling is generally ineffective. The condition can only be cured by prying open the dog’s mouth and manually removing the beetles.