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The pitcher’s morphology appears to have evolved to make this “little service” efficient and safe for itself and the mountain tree shrew.
Evolution charts the path of all living beings and, at first glance, it doesn’t seem to have been very friendly to Nepenthes lowiia type of pitcher plant found in mountain cloud forests on the island of Borneo in Southeast Asia.
The carnivorous plant is regularly visited by mountain tree shrews (Tupaia montana), who feed on it and, at the same time, make it an authentic natural toilet.
As the famous presenter and biologist verified David Attenborough For some years now, the small mammal has gone to the plant to feed on nectar and, while eating, it also feeds the plant its excrement. The pitcher plant uses excrement as a crucial source of nitrogen, a scarce nutrient in that high-altitude environment.
A 2009 study in Biology Letters documents this unusual relationship and suggests that, unlike most pitcher plants, the N. lowii adults no longer depend mainly on insects to obtain nutrients. In many species of Nepenthespoints out, the pitchers have slippery edges and walls that make prey slide into a pool of digestive enzymes. But here the researchers found “little or no” evidence of invertebrate prey in the aerial pitchers, which indicates that these lost the ability to capture animals.
Images collected by cameras installed next to mature specimens show the shrews’ constant behavior: they jump on the plant, lick the nectar deposited on the underside of the lid that covers the opening, and sometimes defecate inside. The videos also recorded the animals scent-marking the jar, rubbing their genitals against the lid before moving away; and they also tend to visit the same “circuit” of plants when feeding.
The morphology of the jar seems to have evolved to make this “little service” efficient and safe for both. Unlike pitchers that capture insects, the rim of the aerial pitcher is not particularly slippery: it helps the animal to stay steady while feeding. The structure is reinforced to support the weight of the shrew (around 150 grams) and the orientation of the lid, covered in nectar, naturally positions the animal’s back over the opening, increasing the probability of deposition of feces in the right place. The funnel shape makes it easier for excrement to be washed inside when it rains.
According to the authors, the strategy makes sense in a mountainous habitat where insects are less abundant. Nutritional analysis indicates that air pitchers can obtain between 57% and 100% of their nitrogen from feces.
Nature really thinks about everything.
