Stenocotis depressa (Walker) Day and Fletcher, 1994

Percy, Diana M. & Day, Max F., 2005, Observations of unusual acoustic behaviour in two Australian leafhoppers (Hemiptera; Cicadellidae), Journal of Natural History 39 (38), pp. 3407-3417 : 3408-3409

Biology of Stenocotis depressa

Little is known about the life cycle of species in five of the six genera of Stenocotini , except that they are all believed to feed on the stems and trunks of smooth-barked Eucalyptus species. The sixth genus is Stenocotis , represented in eastern Australia by a single, large, conspicuous and markedly dimorphic species ( S. depressa , males 10–15 mm, females 21– 24 mm). This species has been frequently collected and is often highly variable in colour, with the result that it has been described under several names by different authors. It is now generally accepted that these are all synonyms of Stenocotis depressa (Walker) ( Day and Fletcher 1994) . This leafhopper has markedly flattened nymphs and the adults are illustrated in Insects of Australia ( Fletcher et al. 1991, Figures 30, 32C). Nymphs and adults are mottled cream and brown, providing excellent camouflage on eucalypt trunks. In the populations studied, males are considerably darker than females or nymphs. When disturbed, males tend to move away rapidly, while females and nymphs tend to remain stationary.

In the Australian Capital Territory (ACT) S. depressa overwinters as an egg. Nymphs appear in early spring (October) with adults approximately 5 months later in summer (December) through to winter (May). The species has been found on several Eucalyptus species ( E. camaldulensis , E. obliqua , E. delagetensis , E. ovata , as well as others), but in ACT most often on E. mannifera . Nymphs and adults may remain stationary for days. Individuals sometimes produce droplets of excreta every few minutes but have not been seen attended by ants, despite the abundant presence of several ant species on the same trunk. At times both nymphs and especially adults are mobile, moving surprisingly fast around a tree trunk; adults also fly but are rarely seen to do so. Males appear to locate females by random search movements around the tree trunk, and occasionally more than one male may attend a single female. Neither adults nor nymphs are able to adhere to the waxy surface of the leaves of the Eucalyptus hosts.