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| [Note Guidelines] Photographer's Note |
This is a very close macro shot therefore the head part is more in focus than the back part.
There are many thousands of species of cicadas, arranged into two families: Tettigarctidae (treated elsewhere) and Cicadidae. There are two extant species of Tettigarctidae, one in southern Australia, and the other in Tasmania. The family Cicadidae is subdivided into the subfamilies Tettigadinae, Cicadinae and Tibicininae, and they occur on all continents except Antarctica.
The largest cicadas are in the genera Pomponia and Tacua. There are some 200 species in 38 genera in Australia, about 450 species in Africa, about 100 in the Palaearctic and exactly one species in England, the New Forest Cicada (Melampsalta montana), which is widely distributed throughout Europe. There are about 150 species in South Africa.
Adult cicadas, sometimes called imagines, are usually between 2 and 5 cm (1 to 2 inches) long, although there are some tropical species that reach 15 cm (6 in), e.g. Pomponia imperatoria from Malaysia. Cicadas have prominent eyes set wide apart on the sides of the head, short antennae protruding between or in front of the eyes, and membranous front wings. Desert cicadas are also one of the few insects known to cool themselves by sweating, while many other cicadas can raise their body temperatures voluntarily to around 40°C, even when the air temperature is only 18°C.
Male cicadas (and only males) have loud noisemakers called "tymbals" on the sides of the abdominal base. Their "singing" is not stridulation as in many other familiar sound-producing insects like crickets (where two structures are rubbed against one another): the tymbals are regions of the exoskeleton that are modified to form a complex membrane with thin, membranous portions and thickened "ribs". They rapidly vibrate these membranes with strong muscles, and enlarged chambers derived from the tracheae make their body serve as a resonance chamber, greatly amplifying the sound. Some cicadas produce sounds louder than 106 dB (SPL), among the loudest of all insect-produced sounds. (This amazing sound has frequently inspired haiku poets in Japan to write about them.) They modulate their noise by wiggling their abdomens toward and away from the tree that they are on.
Only males produce the cicadas' distinctive sound. Both sexes, however, have tympana, which are membranous structures used to detect sounds; thus, the cicadas' equivalent of ears. |
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