Hemsleyana In the Belfry

It could be the increased circulation in the gallery, especially after discovering that the break room had its air conditioning vent shut off for a very valid reason. It could be that this winter was cold but not THAT cold. Heck, it could be that the crowds coming to gallery events since the beginning of the year are considerably lacking in energy vampires. Whatever the factor, there’s an explosion in new growth among the Nepenthes enclosures, with the most spectacular showing with the Nepenthes hemsleyana in the enclosure Bat God. For the first time since the gallery moved here from Valley View Center, this beast of a pitcher plant finally started producing upper traps.

For those unfamiliar with N. hemsleyana, this is an Asian pitcher plant that goes through a fascinating change once it starts producing upper pitchers. Before this point, the lower pitchers it produces are short and squat, pretty much identical to those from its cousin Nepenthes rafflesiana: in fact, until last decade, this plant was considered a rafflesiana subspecies. When the first upper traps form, though, the plant stops secreting digestive enzymes into the fluid in the bottom of each pitcher. Most species of Nepenthes also fluoresce strongly along the lip or peristome under ultraviolet light: N. hemsleyana doesn’t do a thing. This is because in lieu of attracting insects into its pitchers, hemsleyana attracts bats.

The wooly-haired bat Kerivoula hardwickii isn’t trapped by the pitchers: far from it. These tiny bats are some of the smallest in Asia, and they would regularly be bullied out of other nesting sites by larger and more aggressive bats. Instead. K. hardwickii roosts inside of the upper pitchers. The bats get roosts with a minimum of parasites and no predators, and the plant gets both a regular supply of bat guano but, thanks to bats’ fastidious cleaning habits, a supply of bat fur. Both are excellent nitrogen sources, with the fur being more of a slow-release form, which gives the plant more than enough nitrogen and phosphorus to grow.

What is equally interesting is how the bats know that N. hemsleyana pitchers are a suitable roosting site. Right where the lid of the pitcher meets the lip are two very distinctive flanges or fins, and these reflect back a very distinctive sonar signature to the bats emitting it. Anecdotal evidence suggests that the knowledge of this particular sonar signature isn’t instinctive, but that mother bats teach their young the significance of that pingback.

Anyway, this is just one of many surprises turning up in the gallery, all available for viewing when the new gallery debuts. With luck, this hyperactive plant will produce more upper traps: since they don’t produce digestive enzymes, they can’t be fed with insects, but offering the opportunity for visitors to feed the hemsleyana orchid food pellets could be just as interesting. Just don’t start calling the gallery “Stately Wayne Manor.”

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