...their poop.
It uses a special reflective dish that echoes the bat's own calls to bring them in.
In exchange the bat gets a safe place to roost.
De-licious!
http://www.cell.com/current-biology/fulltext/S0960-9822(15)00657-0
Their video doesn't have a good description but in the second part the bat is choosing between a plant with either 1) an unmodified dish, 2) an enlarged dish, 3) a reduced dish, and 4) a completely reduced dish. Bats like big dishes.
https://www.youtube.com/watch?v=_tYcT9RdqGw
It uses a special reflective dish that echoes the bat's own calls to bring them in.
In exchange the bat gets a safe place to roost.

De-licious!
The bat droppings enhance the nitrogen intake of N. hemsleyana by 34% on average. In turn, the pitcher plants provide the bats with roosts that are free of parasites, have a stable microclimate, and offer enough roosting space for one or two bats while at the same time preventing the bats from falling into the digestive fluid due to their unique morphological shape and low fluid level.
That means they constructed a robot bat head and blasted bat echolocation at the pitcher plants with it.To test whether a certain pitcher structure serves as an effective reflector that acoustically stands out in cluttered environments and guides the bats to their target, we measured ultrasound echoes of pitchers from different angles using a biomimetic sonar head.
http://www.cell.com/current-biology/fulltext/S0960-9822(15)00657-0

Their video doesn't have a good description but in the second part the bat is choosing between a plant with either 1) an unmodified dish, 2) an enlarged dish, 3) a reduced dish, and 4) a completely reduced dish. Bats like big dishes.
https://www.youtube.com/watch?v=_tYcT9RdqGw