University of Maryland Extension

Giant Resin Bee

 Female giant resin bee on flower
Female giant resin bee

smaller male giant resin bee
Male giant resin bee is nearly
half the 
size of the female

Have you noticed a different looking large bee flying around your flowering plants lately? Sometimes confused for carpenter bees, mining bees or European hornets they are giant resin bees (Megachile sculpturalis)

Giant resin bees are an introduced species and are native to parts of Asia. It was first confirmed in North Carolina in the early 1990's. They have since spread throughout the southeastern US, including Maryland. 

Giant resin bees are opportunistic and use abandoned wood cavities for nesting. These include holes in trees or timbers or holes created by carpenter bees. Carpenter bees are a native species and a pollinator. Giant resin bees are aggressive towards carpenter bees by depositing a sticky resin on them leaving them immobilized. They then attack the carpenter bee, killing it. 

Giant resin bees are solitary bees and are not known to sting humans unless threatened.  But their impact on native species is troublesome. Spraying for them is not recommended because that would also kill pollinators and natural enemies. 

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