Domatium

A domatium typically takes the form of a hollow under a leaf, or a system of tunnels in a thorn or stem. Ideally, it is a mutualistic adaptation and should not be confused with simple damage by a borer or gall-forming pest, although commonly there is no sharp distinction between domatia of value to the plant and galls caused by harmful aphids and mites, for example.

All are ordinary anatomical features of the plants that the ants exploit, apparently in a unilateral manner. In contrast, the domatia listed comprehensively in Table 14-1 do appear uniquely to serve as ant nests.

Although the earliest work on mites and leaf domatia was inspired by a belief that mites protected trees from fungal disease (O'Dowd and Willson 1989), mite–fungus–plant interactions received experimental attention only recently.

Domatia and extrafloral nectaries are plant structures that provide shelter and food to predaceous arthropods and thus affect herbivorous insects only indirectly.