Spied A Piggyback Beetle

I'd photographed this female crab spider yesterday in the same position on a yarrow flower lunching on a fly. At first sight she seemed to be alone today, though she had her legs spread wide in hunting stance. I knelt down to capture her and noticed a small beetle on the edge of the inflorescence. I thought she was about to pounce but she turned her back on it. I was very surprised when the beetle climbed onto her back. She waggled her legs as if to try to brush it off. It seemed to me that it was dicing with death but it stayed there for a while. It kept its head down. I'm wondering if it was licking at some substance on her body? I've consulted a spider expert on Twitter and he thinks she might be passing it over because it tastes bad owing to cantharidins. I've researched these in a previous blip. https://www.blipfoto.com/entry/2310882980521840072

Today's poem is The Garret by Ezra Pound. https://www.poetryfoundation.org/poetrymagazine/browse?contentId=12667

Nothing better than the hour of waking with one's lover.