Invertebrate Biodiversity (Ants, Bees, and Others) Associated with Stem Domatia of the Indian Myrmecophyte Humboldtia brunonis Wallich (Magnoliophyta: Fabaceae)

The legume tree genus Humboldtia Vahl contains three mutualistic, myrmecophytic species. These trees develop inflated, hollow internodes, which differentiate a single, self-opening entrance hole for each domicile unit. At leaf flush, hundreds of new, accessible, empty domatia are available to any organism capable of entering and defending the hollow space. In terms of abundance, ants are the primary occupant of the hollow internodes of H. brunonis Wallich of India, followed by a bee, Braunsapis sp., and several minor inhabitants including an arboreal annelid. Humboldtia laurifolia Vahl in Sri Lanka is the closest relative of H. brunonis, and we compare and discuss the internode inhabitants of these two geographically separated, but morphologically very similar tree species.