during a trip to Arizona last year I encountered an intriguing mystery...
On the left is a big, toxic darkling beetle in the genus Eleodes. Abundant in the southwest, their quinone-based defensive secretions protect them from most predators (just smelling one made my sinuses burn painfully).
On the right is some sort of large animal droppings containing many Eleodes shells. I couldn’t imagine what sort of animal would eat them and produce such large droppings. I theorized that it was a pellet coughed up by a large bird like an owl or roadrunner, but couldn’t find any info to suggest anything like that is resistant to the beetle toxins.
I still had no idea what was behind these droppings for many months after the trip, but I finally realized the culprit, a beast that I had been lucky enough to encounter while I was there:
It was the the Sonoran desert toad, Incilius alvarius. One of the world’s largest toads, it is apparently immune to the secretions of the darkling beetles in its desert habitat and eats them as a large portion of its diet.
It’s also the toad species known for the powerful psychedelic properties of its skin secretions (though contrary to popular belief, licking the toad is ineffective and extremely dangerous. Consuming the raw toad toxin can easily kill you.) Furthermore, there’s anecdotal evidence that the toads actually require darkling beetles to manufacture their toxin, which makes sense as smaller american toads have been reported to require similarly toxic carabid beetles for the same reason.
TL;DR I found some weird poop with beetles in it and was too dumb to realize until later that it came from the giant drug toads