Tymbal
Encyclopedia
Tymbal is a term for a corrugated exoskeletal
structure used to produce sounds in insects. In male cicada
s, the tymbals are membranes in the abdomen, responsible for the characteristic sound produced by the insect. In tiger moth
s, the tymbals are modified regions of the thorax
, and produce high-frequency clicks.
The paired tymbals of a cicada are located on the sides of the abdominal
base. The "singing" of a cicada is not stridulation
as in many other familiar sound-producing insects like crickets
(where one structure is rubbed against another): the tymbals are regions of the exoskeleton
that are modified to form a complex membrane with thin, membranous portions and thickened "ribs". These membranes vibrate rapidly, and enlarged chambers derived from the tracheae
make the cicada's 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. They modulate their noise by positioning their abdomens toward or away from the substrate.
The tymbals of a tiger moth are specialized regions on the metathoracic
episterna, normally corrugated such that sound is produced when the entire tymbal surface is buckled by muscular contraction and then released, producing a series of extremely rapid "clicks" as the corrugations flex back into place. These sounds are only occasionally audible to humans, and are used in both acoustic aposematism
(the moths are advertising to bats that they are toxic), and as mating signals. A recent study claims that these sounds could be used to "jam" the sonar of moth-eating bats
Exoskeleton
An exoskeleton is the external skeleton that supports and protects an animal's body, in contrast to the internal skeleton of, for example, a human. In popular usage, some of the larger kinds of exoskeletons are known as "shells". Examples of exoskeleton animals include insects such as grasshoppers...
structure used to produce sounds in insects. In male cicada
Cicada
A cicada is an insect of the order Hemiptera, suborder Auchenorrhyncha , in the superfamily Cicadoidea, with large eyes wide apart on the head and usually transparent, well-veined wings. There are about 2,500 species of cicada around the world, and many of them remain unclassified...
s, the tymbals are membranes in the abdomen, responsible for the characteristic sound produced by the insect. In tiger moth
Tiger moth
Tiger moths are moths of the family Arctiidae.Tiger moth may also refer to:*de Havilland Tiger Moth, an aircraft; an aerobatic and trainer tailwheel biplane*de Havilland DH.71 Tiger Moth, an earlier monoplane produced by de Havilland...
s, the tymbals are modified regions of the thorax
Thorax
The thorax is a division of an animal's body that lies between the head and the abdomen.-In tetrapods:...
, and produce high-frequency clicks.
The paired tymbals of a cicada are located on the sides of the abdominal
Abdomen
In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...
base. The "singing" of a cicada is not stridulation
Stridulation
Stridulation is the act of producing sound by rubbing together certain body parts. This behavior is mostly associated with insects, but other animals are known to do this as well, such as a number of species of fishes, snakes and spiders...
as in many other familiar sound-producing insects like crickets
Cricket (insect)
Crickets, family Gryllidae , are insects somewhat related to grasshoppers, and more closely related to katydids or bush crickets . They have somewhat flattened bodies and long antennae. There are about 900 species of crickets...
(where one structure is rubbed against another): the tymbals are regions of the exoskeleton
Exoskeleton
An exoskeleton is the external skeleton that supports and protects an animal's body, in contrast to the internal skeleton of, for example, a human. In popular usage, some of the larger kinds of exoskeletons are known as "shells". Examples of exoskeleton animals include insects such as grasshoppers...
that are modified to form a complex membrane with thin, membranous portions and thickened "ribs". These membranes vibrate rapidly, and enlarged chambers derived from the tracheae
Invertebrate trachea
The invertebrate trachea refers to the open respiratory system composed of spiracles, tracheae, and tracheoles that terrestrial arthropods have to transport metabolic gases to and from tissues....
make the cicada's body serve as a resonance
Resonance
In physics, resonance is the tendency of a system to oscillate at a greater amplitude at some frequencies than at others. These are known as the system's resonant frequencies...
chamber, greatly amplifying the sound. Some cicadas produce sounds louder than 106 dB (SPL), among the loudest of all insect-produced sounds. They modulate their noise by positioning their abdomens toward or away from the substrate.
The tymbals of a tiger moth are specialized regions on the metathoracic
Metathorax
The metathorax is the posterior of the three segments in the thorax of an insect, and bears the third pair of legs. Its principal sclerites are the metanotum , the metasternum , and the metapleuron on each side...
episterna, normally corrugated such that sound is produced when the entire tymbal surface is buckled by muscular contraction and then released, producing a series of extremely rapid "clicks" as the corrugations flex back into place. These sounds are only occasionally audible to humans, and are used in both acoustic aposematism
Aposematism
Aposematism , perhaps most commonly known in the context of warning colouration, describes a family of antipredator adaptations where a warning signal is associated with the unprofitability of a prey item to potential predators...
(the moths are advertising to bats that they are toxic), and as mating signals. A recent study claims that these sounds could be used to "jam" the sonar of moth-eating bats