Zabalius aridus Ear Dorsolateral 2012 06 04 6748

CSIRO ScienceImage 2673 The Hearing Organs of Two Moths

A tympanal organ (or tympanic organ) is a hearing organ in

insects Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs of j ...

, consisting of a membrane ( tympanum) stretched across a frame backed by an air sac and associated

sensory neuron Sensory neurons, also known as afferent neurons, are neurons in the nervous system, that convert a specific type of stimulus, via their receptors, into action potentials or graded potentials. This process is called sensory transduction. The ...

s. Sounds vibrate the membrane, and the vibrations are sensed by a

chordotonal organ Chordotonal organs are stretch receptor organs found only in insects and crustaceans. They are located at most joints and are made up of clusters of scolopidia that either directly or indirectly connect two joints and sense their movements relati ...

Hymenoptera Hymenoptera is a large order of insects, comprising the sawflies, wasps, bees, and ants. Over 150,000 living species of Hymenoptera have been described, in addition to over 2,000 extinct ones. Many of the species are parasitic. Females typic ...

(bees, wasps, ants, etc.) do not have a tympanal organ, but they do have a

Johnston's organ Johnston's organ is a collection of sensory cells found in the pedicel (the second segment) of the antennae in the class Insecta. Johnston's organ detects motion in the flagellum (third and typically final antennal segment). It consists of scol ...

. Tympanal organs occur in just about any part of the insect: the

thorax The thorax or chest is a part of the anatomy of humans, mammals, and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main divisions of the c ...

, the base of the wing, the

abdomen The abdomen (colloquially called the belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the to ...

, the legs, etc., depending on the group of insects. The structures are thought to have evolved independently many times. As a result, their position and structures are often used to help determine the

taxonomy Taxonomy is the practice and science of categorization or classification. A taxonomy (or taxonomical classification) is a scheme of classification, especially a hierarchical classification, in which things are organized into groups or types. ...

of the species. For example, all members of the

Geometridae The geometer moths are moths belonging to the family Geometridae of the insect order Lepidoptera, the moths and butterflies. Their scientific name derives from the Ancient Greek ''geo'' γεω (derivative form of or "the earth"), and ''metro ...

share distinctive paired abdominal tympanal organs that open towards the front side of the first abdominal segment. Within the organ, particular structures vary in shape and are used to indicate shared ancestry of subfamilies. In other families of

Lepidoptera Lepidoptera ( ) is an order of insects that includes butterflies and moths (both are called lepidopterans). About 180,000 species of the Lepidoptera are described, in 126 families and 46 superfamilies, 10 percent of the total described speci ...

having abdominal tympanal organs, the opening may be in a different orientation and the structures differ in shape. Tympanal organs have evolved in Lepidoptera to allow them to detect the echolocation calls of predatory bats. The range of frequencies that the moth is most sensitive to is usually associated with the frequencies used in echolocation by the sympatric bat community. In the presence of predatory bats, it has been shown that the Lepidoptera species ''

Mythimna unipuncta ''Mythimna unipuncta'', the true armyworm moth, white-speck moth, common armyworm or rice armyworm, is a nocturnal agricultural pest belonging to the family Noctuidae. This moth is also commonly referred to by the scientific name ''Pseudaletia u ...

'' (true armyworm) stops mating behaviors, such as female calling and male wing flapping. As well, hearing is important for mating behaviors in this species because females increase their flapping frequency around males and males produce a trembling noise in response.Fitzpatrick, Sheila M., and Jeremy N. Mcneil. “Male Scent In Lepidopteran Communication: The Role Of Male Pheromone In Mating Behaviour Of Pseudaletia Unipuncta (Haw.) (Lepidoptera: Noctuidae).” ''Memoirs of the Entomological Society of Canada'', vol. 120, no. S146, 1988, pp. 131–151., doi:10.4039/entm120146131-1.

References

{{cite book , last1=Scoble, first1=MJ. , title=The Lepidoptera: Form, function, and diversity. , url=https://archive.org/details/lepidopteraformf0000scob, url-access=registration, year=1992 , publisher=Oxford Univ. Press, isbn=978-1-4020-6242-1 Insect anatomy Sensory organs in animals

See also

References