Umbonia crassicornis, commonly known as the thorn bug, is a widespread member of the insect family Membracidae, and an occasional pest of ornamentals and fruit trees in southern Florida. The body length of the adult is approximately . This is a variable species as to size, color and structure, particularly the pronotal horn of males (which is more angled posteriorly than the females' and often somewhat expanded apically). This tall, essentially perpendicular thorn-like pronotum discourages birds and other predators from eating it, if only by mistakenly confusing it with a thorn. Typically, the adult is green or yellow with reddish lines and brownish markings. Distribution The species is restricted to warmer climates where temperatures stay, on average, above zero. This limits the species to the tropical regions of Northern South America to Mexico and Florida. Any range of temperature below 0 degrees is fatal resulting in a 10-90 percent decrease in the population as temperature decreases. Its preferred hosts are ornamental and fruit trees of subtropical regions feeding on sap inside the plants. Reproduction Female Umbonia crassicornis often deposit about 100 eggs at a time into a plant stem, under the bark. However, sometimes a female will lay her eggs in the leaf petiole even though they can be shed occasionally. The female will choose her brooding site based on if she can wrap her legs around the branch (diameter about 3.8mm) The mother will stay with the clutch (a group of young) until the nymphs are mature. Without an adult female present during the nymphs development, the survival rate of the clutch drops from 53% survival to 27%. If a clutch's defending female dies, the clutch can be adopted by a nearby female and the two clutches will combine into one, though the survival rate decreases significantly. A clutch normally consists of all full siblings, since the female usually only mates once, and sibling are more likely to defend each other based on this close relatedness. A problem with a large group of closely related young growing up together is the possibility of Inbreeding once the individuals reach reproductive maturity. When this happens survival rate of the offspring drops significantly due to mutations cause my mating with a sibling. Mate selection Because a female U. crassicornis only mates once in her life (typically), males are forced to search and compete for a female. They do this using the 'fly-call-walk'