I've heard of birds nesting in trees and insects building homes in foliage, but bats in pitcher plants? So interesting!
In Borneo, carnivorous pitcher plants (Nepenthes hemsleyana) figured out a way to get bat guano (fertilizer) delivered for free. They offer bats (Kerivoula hardwickii) their vase-shaped leaves as natural sleeping bags to spend the daylight hours in protected comfort.
Apparently, the plants advertise the comfy roost as well. They have evolved a way to reflect back the bats' high frequency sonar in a 5 star luxury hotel way (compared to the 1 star surrounding plants). The thin pitcher shape is crucial to the habitat marketing and allows the bats to find them easily and settle in.
In the past, scientists reported tropical plants that evolved sonic skills to attract bats as pollinators. This is the first time a plant has used sound to call the hogs (er... bats in for the night). Go science!