A great number of
infaunal organisms have been found in the pitchers of this species. These include the
sarcophagid fly Sarcophaga papuensis and the
mite Nepenthacarus warreni, which have both been found in Australian populations of the plant. Similarly, the
mosquitoes
Aedes dybasi and
Aedes maehleri reside in the pitchers of
N. mirabilis on the islands of
Palau and
Yap, respectively. Both have unusual life histories and morphological traits associated with this habit. The
nematode Baujardia mirabilis has been described from
N. mirabilis in
Thailand. It is not thought to be accidental; the pitchers of this species appear to be the nematode's natural habitat. The microecosystems in these pitchers were found to be dominated by mosquito larvae, midges, and
B. mirabilis. It is speculated that this nematode might have a
phoretic relationship with one or more infaunal insect species. In southern China,
tree frogs have been observed in the pitchers of
N. mirabilis. The amphibians do not fall prey to the plant, but rather feed on insects that are caught by the pitchers. They are not affected by the
acidic digestive juices (which may have a
pH as low as 2), likely due to the
mucilaginous outer layer of their skin. The first record of an aquatic
fungus living in the pitcher organ of a
carnivorous plant came from a specimen of
N. mirabilis growing along the
Jardine River in Australia. The
mycelial fungus was observed as both free-living in the trap's fluid and attached to
chitinous insect remains. The pitchers of
N. mirabilis have also been found to harbour a complex community of
bacteria. These bacterial communities appear to be more diverse than those found in the pitcher fluid of
N. ampullaria and sympatric
N. gracilis in
Peninsular Malaysia. In
N. mirabilis their composition can also differ significantly according to pitcher type, something not seen in the other two species. ==Natural hybrids==