It is my understanding that most pollinating bats prefer to land on something while feeding, if possible, because they are very poor at hovering in one spot, in the manner of a moth or hummingbird. There is frequently substantial damage to flowers when bats feed, due to them crawling around on the flower and plant. Most bat-pollinated flowers tend to be quite wide in relation to their length, with sturdy, thick, or even waxy perianth segments. They also are borne closely to the stem, if not sessile. Such architecture more readily supports a mammal. Pamianthe appears not strong enough to support even smaller bats. In addition, many bats feed on pollen as well as nectar, and Pamianthe does not appear to produce much of that when compared to such plants as the cacti in genus Pilosocereus or Pachycereus pringlei, known to be bat pollinated. These have wide, short flowers with thick perianth segments, held closely to the stems, and are presented horizontally or vertically. Moth-pollinated flowers, as noted in this discussion, are often long-tubed and somewhat diaphenous. While bat-pollinated flowers sometimes have a fruity fragrance, more often they smell sour, like something fermented, or musty. (Pachycereus pringlei smells like Juicy Fruit chewing gum and most Pilosocereus species like something left in the washing machine too long.) The cactus genera and are examples of this, and some members of Echinopsis have long, fragrant, night-blooming flowers. Fragrances we humans consider sweet often are produced by moth-pollinated plants such as Angraecum, Cereus, Brugmansia, Datura, Gardenia, Hylocereus, Jasminum, Lilium (bulb content!) Nicotiana, Peniocereus, Petunia, Selenicereus and Polianthes (more bulb content!!). These flowers all have a ring of stamens oriented in a manner that dusts visiting moths, proboscideally probing floral depths, and a pistil that moths must push away while feeding. So I would vote for moths pollinating Pamianthe. The matter could be settled by observation. I would be willing to undertake an expedition to observe Pamianthe in habitat during bloom season. Since that would be somewhat unpredictable, I would need to spend quite a bit of time there. If anybody would like to sponsor me, please contact me. Leo Martin Phoenix Arizona USA