Location: South Africa, Gauteng
October 30, 2010 6:07 pm
Found this in a big tree with yellow flowers. They have been there for the last 3 weeks and did not change in that time
We wish you had provided additional information. We would really love to know the size of these creatures and the identity of the plant species might also prove very helpful. The closest we have seen to anything like this are the Spittlebugs in the family Cercopidae. Here is an image from BugGuide. There are many North American species and they are small insects. The immature nymphs form a mass of spittle that they use for protection, and they are occasionally found in groupings with their siblings. Spittlebugs feed on the fluids from the plants which they extract with their sucking mouthparts. According to BugGuide: “nymphs surround themselves with a frothy mass that resembles spittle” and “The ‘spittle’ is derived from a fluid voided from the anus and from a mucilaginous substance excreted by epidermal glands.” Based on this information, we will attempt to provide you with a species identification, but we would appreciate any additional information you are able to provide to us. We are not certain if there are other Free-Living Hemipterans in the suborder Auchenorrhyncha that exhibit a similar habit with the immature phase, but that is also a possibility.
Immediate Update: Moments after posting, we did a search of Spittlebugs South Africa and we found the Fieldguide to Insects of South Africa Google books by Mike Picker, Charles Griffiths and Alan Weaving which includes the following description of the Rain-Tree Bug or Tipuana Spittle Bug, Ptyelus grossus: “Identification: Large (wingspan 30-35 mm), with slate grey wings, marked with 2 large cream and orange spots and smaller cream dots. Nymphs (4A) black with fine cream hieroglyphic-type markings and central orange stripe. Biology: Well known for the phenomenon of ‘rain-trees’, produced by the constant dripping of processed tree sap through the bodies of clusters of nymphs and adults.” The Google Book also contains an image of a solitary nymph outside of the spittle mass. Wikipedia Commons has a matching image of the nymphs. We are unable to locate any additional information on this species.
Update October 19, 2015
In researching a new comment, we did more research and we learned this on the Flora of Zimbabwe site: “The spittle bug, Ptyelus grossus, is common in Zimbabwe and occurs in large numbers on the rain tree Philenoptera violacea but are also found on other trees like Tipuana tipu and Rauvolfia caffra. The spittle bug feeds on the sap of the plant by piercing the bark of the tree with their stylets (sucking mouthparts) and sucking the sap at great speed. The plant sap is a weak solution of sugars and salts and the insect has to consume a great deal in order to obtain sufficient nourishment, so they eject almost pure water equally fast. This drips from the tree in sufficient quantities to form pools on the ground below and infested trees have acquired the name ‘rain tree’.”