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Apiarist reporting in. You guys are pretty right about this scent-thing. Basically they recognize the smell of their sisters intestines and that makes them, what a surprise, mad. Dealing an ape shit crazy hornet is not funny since they have excellent eye sight and basically know no fear. Unlike bees hornets and wasps can use their stinger multiple times.
I recommend wearing several layers of clothing, ducktape, thick silicon gloves, a hat and some mosquito net. You should be able to make yourself an "insect-safe" suit with said materials. Make sure to seal every entry and also keep an eye on the net having enough air between your skin and the hornets. Now you don't need to be scared anymore and can inspect your kitchen.
By the way: They indeed have a memory. They can memorize food sources, possible threats and probably also you since you are officially a threat now. For a hornet colony the single individual is much more precious than it is for bees or wasps because their sizes are way smaller. Since it's still pretty early this year you have a good chance that hornet colony not being bigger than maybe 50 animals.
