Stridulation

Key takeaways

Stridulation belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Stridulation to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Stridulation from memory before moving on to harder problems.

Reference excerpt

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 fish, snakes and spiders. The mechanism is typically that of one structure with a well-defined lip, ridge, or nodules (the "scraper" or plectrum) being moved across a finely-ridged surface (the "file" or stridulitrum—sometimes called the pars stridens) or vice versa, and vibrating as it does so, like the dragging of a phonograph needle across a vinyl record. Sometimes it is the structure bearing the file which resonates to produce the sound, but in other cases it is the structure bearing the scraper, with both variants possible in related groups. Common onomatopoeic words for the sounds produced by stridulation include chirp and chirrup.

Arthropod stridulation

Insects and other arthropods stridulate by rubbing together two parts of the body. These are referred to generically as the stridulatory organs.

The mechanism is best known in crickets, mole crickets, and grasshoppers, but other insects which stridulate include Curculionidae (weevils and bark beetles), Cerambycidae (longhorned beetles), Mutillidae ("velvet ants"), Reduviidae (assassin bugs), Buprestidae (metallic wood-boring beetles), Hydrophilidae (water scavenger beetles), Cicindelinae (tiger beetles), Scarabaeidae (scarab beetles), Glaresidae ("enigmatic scarabs"), larval Lucanidae (stag beetles), Passalidae (Bessbugs), Geotrupidae (earth-boring dung beetles), Alydidae (broad-headed bugs), Largidae (bordered plant bugs), Miridae (leaf bugs), Corixidae (water boatmen, notably Micronecta scholtzi), various ants (including the Black imported fire ant, Solenopsis richteri), some stick insects such as Pterinoxylus spinulosus, and some species of Agromyzidae (leaf-mining flies). While cicadas are well-known for sound production via abdominal tymbal organs, it has been demonstrated that some species can produce sounds via stridulation, as well. Stridulation is also known in a few tarantulas (Arachnida), certain centipedes, such as Scutigera coleoptrata, and some pill millipedes (Diplopoda, Oniscomorpha). It is also widespread among decapod crustaceans, e.g., rock lobsters. Most spiders are silent, but some tarantula species are known to stridulate. When disturbed, Theraphosa blondi, the Goliath tarantula, can produce a rather loud hissing noise by rubbing together the bristles on its legs. This is said to be audible to a distance of up to 15 feet (4.5 m). One of the wolf spiders, Schizocosa stridulans, produces low-frequency sounds by flexing its abdomen (tremulation, rather than stridulation) or high-frequency stridulation by using the cymbia on the ends of its pedipalps. In most species of spiders, stridulation commonly occurs by males during sexual encounters. In the species Holocnemus pluchei, females also possess stridulatory organs, and both sexes engage in stridulation. In the species Steatoda nobilis, the males produce stridulation sounds during mating. The anatomical parts used to produce sound are quite varied: the most common system is that seen in grasshoppers and many other insects, where a hind leg scraper is rubbed against the adjacent forewing (in beetles and true bugs the forewings are hardened); in crickets and katydids a file on one wing is rubbed by a scraper on the other wing; in longhorned beetles, the back edge of the pronotum scrapes against a file on the mesonotum; in various other beetles, the sound is produced by moving the head—up/down or side-to-side—while in others the abdominal tergites are rubbed against the elytra; in assassin bugs, the tip of the mouthparts scrapes along a ridged groove in the prosternum; in velvet ants the back edge of one abdominal tergite scrapes a file on the dorsal surface of the following tergite.

Stridulation in several of these examples is for attracting a mate, or as a form of territorial behaviour, but can also be a warning signal (acoustic aposematism, as in velvet ants and tarantulas). This kind of communication was first described by Slovenian biologist Ivan Regen (1868–1947).

Vertebrate stridulation Some species of venomous snakes stridulate as part of a threat display. They arrange their body into a series of parallel C-shaped (counterlooped) coils that they rub together to produce a sizzling sound, rather like water on a hot plate. The best-known examples are members of the genus Echis (saw-scaled vipers), although those of the genus Cerastes (North African desert vipers) and at least one bush viper species, Atheris desaixi, do this as well. A bird species, the club-winged manakin, has a dedicated stridulation apparatus, while a species of mammal, the lowland streaked tenrec, (Hemicentetes semispinosus) produces a high-pitched noise by rubbing together specialised quills on its back.

References

External links The British Library Sound Archive contains over 150,000 recordings of animal sounds and natural atmospheres from around the world. https://www.archentoflor.com/araign%E9e%20stridulatoire.htm

Illustrations

Worked examples

Example 1 — a first encounter with Stridulation

Start with the simplest possible case. Write down what Stridulation claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Stridulation before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Stridulation ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Stridulation

In research: Stridulation appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Stridulation in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Stridulation is common in secondary-school and first-year university syllabi. It links to neighbouring topics Animal sounds, Insect behavior, Sound, so understanding it makes those chapters shorter.
In everyday life: Look for Stridulation outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study Stridulation in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Stridulation means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Stridulation out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Stridulation in simple terms?

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 fish, snakes and spiders.

Why does Stridulation matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Stridulation?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Stridulation.