Wasps on runner beans

That's interesting. I have wasps that are using our sweetcorn as a B&B by tucking themselves as far they can into the 'tubes' formed by the leaves. During the day, they come out and scout out the rest of the veg patch but in particular the brassicas for insects to haul away. Despite the number of cabbage whites flying around, I've only seen three clutches of eggs this year and one caterpillar thanks to the wasps.

Might they actually be removing pests from your beans, and it's the pests that have caused the damage, not the wasps?

It doesn't sound like that's the case from your description, but it's the only thing I can think of.

I should also add the wasps we have in our sweetcorn are nothing like as aggressive as wasps that make nests. We love sweetcorn, but even if we didn't I'd grow it just for the wasps.

Never heard of wasps having a go at runner beans , they normally feed the wasp grubs on insects , slugs etc and feed on what the grubs excrete.
Could they be taking slugs from the beans?
A hard shower of rain will slow them down and make them take shelter where they can.

Wasps are capable of rasping wood off fence panels to use in nest building ..........

are your beans really THAT woody ?           

I noticed wasps on my runners last year, and those brown patches which i thought were from stings too. 

This year they are all over my plum tree and making those inedible.

I think it on Beechgrove that they used wasps to control whitefly. I have seen a few on my beans so maybe thats what they are doing.
A few years ago i did notice loads of hover-flies on the beans and i ended up with a bumper crop.
This year i have had loads of bees and getting lots of beans.

I haven't noticed them on my beens but I certainly have a lot about and they are doing some strange things. Like coming indoors and what looks like pollinating only a few varieties of chillies 

My understanding is that wasps feed their grubs with insects (greenfly etc.) during the summer but in early autumn (i.e. starting about now) the queen stops laying and the grubs stop growing so the wasps have no food and have to find sugar to live on. Hence them attacking strawberry jam. Could it be the same, are they feeding on the beans?