The spittle bug (
Ptyelus grossus), also known as the rain-tree bug, occurs in bushveld areas os Southern Africa. They are gregarious in their larval and nymph stages, and at certain times of the year you might find hundreds congregating on a variety of trees and shrubs. They huddle closely together, using their drill-like mouthparts to feed on the cambium layer of their host plant and excreting a protective nest from a combination of the plant’s sap and oxygen. This foamy, processed sap insulates the nest against excessive heat and cold, prevents the larvae from drying out, and resembles spit, hence the name ‘spittle bug’. It accumulates and falls constantly, causing the ‘rain-tree’ phenomenon.
The African wattle and the apple leaf trees are favoured hosts, but spittle bugs may also be found feeding on Acacia trees and many varieties of shrub. So next time you’re under a tree in the bush and you feel a little rain on your skin, it’s more than likely a nest of spittle bugs doing what they do best. But don’t take it personally, they spit on everyone!
The rain-tree or apple-leaf tree (
Philenoptera violacea) gets its nickname because of its relationship with spittle bugs. The tree is frequently attacked by spittle bugs that feed on the tree’s cambium layer, and the bugs then excrete a foamy sap that insulates them from drying out. This ‘spit’ can accumulate in great quantities and ‘rain’ down on the ground below, hence the name rain-tree. In effect this relationship between tree and insect allows the tree to use its own moisture and ‘re-water’ itself in drought conditions. The spittle bugs cause exudation of water from stem and branches to such an extent that the ground or area covered by this plant is wet, allowing it to use the moisture in drought conditions.
A real drought survivor!
Nymphs with bubble
Adult
