Seismic or vibrational communication is a process of conveying
information
Information is an abstract concept that refers to that which has the power to inform. At the most fundamental level information pertains to the interpretation of that which may be sensed. Any natural process that is not completely random ...
through mechanical (
seismic
Seismology (; from Ancient Greek σεισμός (''seismós'') meaning "earthquake" and -λογία (''-logía'') meaning "study of") is the scientific study of earthquakes and the propagation of elastic waves through the Earth or through other ...
)
vibration
Vibration is a mechanical phenomenon whereby oscillations occur about an equilibrium point. The word comes from Latin ''vibrationem'' ("shaking, brandishing"). The oscillations may be periodic function, periodic, such as the motion of a pendulum ...
s of the substrate. The substrate may be the earth, a plant stem or leaf, the surface of a body of water, a spider's web, a honeycomb, or any of the myriad types of soil substrates. Seismic cues are generally conveyed by surface
Rayleigh or bending waves generated through vibrations on the substrate, or acoustical waves that couple with the substrate. Vibrational communication is an ancient sensory modality and it is widespread in the animal kingdom where it has evolved several times independently. It has been reported in mammals, birds, reptiles, amphibians, insects, arachnids, crustaceans and nematode worms.
[Hill, P.S.M., (2008). ''Vibrational Communication in Animals.'' Harvard, Cambridge, London] Vibrations and other communication channels are not necessarily mutually exclusive, but can be used in multi-modal communication.
Functions
Communication requires a sender, a message, and a recipient, although neither the sender or receiver need be present or aware of the other's intent to communicate at the time of communication.
Intra-specific communication
Vibrations can provide cues to conspecifics about specific behaviours being performed, predator warning and avoidance, herd or group maintenance, and courtship.
The
Middle East blind mole-rat
The Middle East blind mole-rat or Palestine mole-rat (''Nannospalax ehrenbergi'') is a species of rodent in the family Spalacidae.
Taxonomy
It was formerly classified in the genus ''Spalax'', but more recent phylogenetic evidence supports it a ...
(''Spalax ehrenbergi'') was the first mammal for which vibrational communication was documented. These
fossorial
A fossorial () animal is one adapted to digging which lives primarily, but not solely, underground. Some examples are badgers, naked mole-rats, clams, meerkats, and mole salamanders, as well as many beetles, wasps, and bees.
Prehistoric eviden ...
rodents bang their head against the walls of their tunnels, which was initially interpreted as part of their tunnel building behaviour. It was eventually realised they generate temporally patterned vibrational signals for long-distance communication with neighbouring mole-rats.
Footdrumming is used widely as a predator warning or defensive action. It is used primarily by fossorial or semi-fossorial rodents, but has also been recorded for
spotted skunk
The genus ''Spilogale'' includes all skunks commonly known as spotted skunks. Currently, there are four accepted extant species: ''S. gracilis'', ''S. putorius'', ''S. pygmaea'', and ''S. angustifrons''. New research, however, proposes that ther ...
s (''Spilogale putorius''),
deer
Deer or true deer are hoofed ruminant mammals forming the family Cervidae. The two main groups of deer are the Cervinae, including the muntjac, the elk (wapiti), the red deer, and the fallow deer; and the Capreolinae, including the reindeer ...
(e.g. white-tailed deer ''Odocoileus virginianus''), marsupials (e.g.
tammar wallabies ''Macropus eugenii''), rabbits (e.g.
European rabbits ''Oryctolagus cuniculus'') and
elephant shrew
Elephant shrews, also called jumping shrews or sengis, are small insectivorous mammals native to Africa, belonging to the family Macroscelididae, in the order Macroscelidea. Their traditional common English name "elephant shrew" comes from a pe ...
s (Macroscelididae).
[Randall, J.A., (2001). Evolution and function of drumming as communication in mammals. American Zoologist, 41: 1143–1156] Banner-tailed kangaroo rats (''
Dipodomys spectabilis
The banner-tailed kangaroo rat (''Dipodomys spectabilis'') is a species of rodent in the family Heteromyidae. It is found in arid environments in the southwestern United States and Mexico where it lives in a burrow by day and forages for seeds an ...
'') footdrum in the presence of snakes as a form of individual defense and parental care.
[Randall, M.D. and Matocq, J.A., (1997). Why do kangaroo rats (Dipodomys spectabilis) footdrum at snakes? Behavioural Ecology, 8: 404–413] Several studies have indicated intentional use of
ground vibrations Ground vibrations is a technical term that is being used to describe mostly man-made vibrations of the ground, in contrast to natural vibrations of the Earth studied by seismology. For example, vibrations caused by explosions, construction works, ra ...
as a means of intra-specific communication during courtship among the
Cape mole-rat (''Georychus capensis'').
[Narins, P.M., Reichman, O.J., Jarvis, J.U.M. and Lewis, E.R., (1992). Seismic signal transmission between burrows of the Cape mole-rat Georychus capensis. Journal of Comparative Physiology 170: 13–22] Footdrumming has been reported to be involved in male-male competition where the dominant male indicates its resource holding potential by drumming, thus minimising physical contact with potential rivals. The
Asian elephant
The Asian elephant (''Elephas maximus''), also known as the Asiatic elephant, is the only living species of the genus ''Elephas'' and is distributed throughout the Indian subcontinent and Southeast Asia, from India in the west, Nepal in the no ...
(''Elephas maximus'') uses seismic communication in herd or group maintenance
[O’Connell-Rodwell, C.E., Arnason, B. and Hart, L.A., (2000). Seismic properties of elephant vocalizations and locomotion. Journal of the Acoustical Society of America, 108: 3066–3072] and many social insects use seismic vibrations to coordinate the behaviour of group members, for example in cooperative foraging.
Other insects use vibrational communication to search for and attract mates, like
North American treehoppers, ''Enchenopa binotata''. Males of this species use their abdomen to send vibrations through their host plant's stem. Females perceive these signals and respond to them to initiate a duet.
Inter-specific communication
The banner-tailed kangaroo rat, (''Dipodomys spectabilis),'' produces several complex footdrumming patterns in a number of different contexts, one of which is when it encounters a snake. The footdrumming may alert nearby offspring but most likely conveys that the rat is too alert for a successful attack, thus preventing the snake's predatory pursuit.
Vibrations caused by stampeding animals may be sensed by other species to alert them to danger, thereby increasing the size of the stampede and reducing the risk of danger to an individual.
Eavesdropping
Some animals use
eavesdropping
Eavesdropping is the act of secretly or stealthily listening to the private conversation or communications of others without their consent in order to gather information.
Etymology
The verb ''eavesdrop'' is a back-formation from the noun ''eaves ...
to either catch their prey or to avoid being caught by predators. Some snakes are able to perceive and react to substrate-borne vibrations. The vibrations are transmitted through the lower jaw, which is often rested on the ground and is connected with the inner ear. They also detect vibrations directly with receptors on their body surface. Studies on horned desert vipers (''
Cerastes cerastes
''Cerastes cerastes'', commonly known as the Saharan horned viperMallow D, Ludwig D, Nilson G. (2003). ''True Vipers: Natural History and Toxinology of Old World Vipers''. Malabar, Florida: Krieger Publishing Company. . or the desert horned viper ...
'') showed they strongly rely on vibrational cues for capturing prey. Localisation of the prey is probably aided by the two halves of the lower jaw being independent.
Vibrational cues can even indicate the life stage of prey thereby aiding optimal prey selection by predators, e.g.
larva
A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle.
The ...
l vibrations can be distinguished from those generated by
pupa
A pupa ( la, pupa, "doll"; plural: ''pupae'') is the life stage of some insects undergoing transformation between immature and mature stages. Insects that go through a pupal stage are holometabolous: they go through four distinct stages in their ...
e, or, adults from juveniles. Although some species can conceal or mask their movements, substrate-borne vibrations are generally more difficult to avoid producing than airborne vibrations.
[Hill, P.S.M., (2009). How do animals use substrate-borne vibrations as an information source? Naturwissenschaften, 96: 1355–1371. doi:10.1007/s00114-009-0588-8] The common angle moth (''
Semiothisa aemulataria'') caterpillar escapes predation by lowering itself to safety by a silk thread in response to vibrations produced by approaching predators.
Mimicry
Several animals have learnt to capture prey species by mimicking the vibrational cues of their predators.
Wood turtle
The wood turtle (''Glyptemys insculpta'') is a species of turtle endemic to North America. It is in the genus ''Glyptemys'', a genus which contains only one other species of turtle: the bog turtle (''Glyptemys muhlenbergii'' ). The wood turtle ...
s (''Clemmys insculpta''),
[Kaufmann, J.H. (1986) Stomping for earthworms by wood turtles, Clemmys insculpta: a newly discovered foraging technique. Copeia, 1986: 1001–1004] European herring gull
The European herring gull (''Larus argentatus'') is a large gull, up to long. One of the best-known of all gulls along the shores of Western Europe, it was once abundant. It breeds across Northern Europe, Western Europe, Central Europe, Eastern ...
s (''Larus argentatus''),
[Tinbergen, N., (1960). ''The Herring Gull's World.'' New York: Basic Books, Inc.] and
humans
Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, ...
[Catania, K.C., (2008). Worm grunting, fiddling, and charming — humans unknowingly mimic a predator to harvest bait. Public Library of Science ONE, 3(10): e3472. doi:10.1371/journal.pone.000347]
/ref> have learnt to vibrate the ground causing earthworms to rise to the surface where they can be easily caught. It is believed that deliberately produced surface vibrations mimic the seismic cues of moles moving through the ground to prey on the worms; the worms respond to these naturally produced vibrations by emerging from their burrows and fleeing across the surface.
Other animals mimic the vibrational cues of prey, only to ambush the predator when it is lured towards the mimic. Assassin bug
The Reduviidae are a large cosmopolitan family of the order Hemiptera (true bugs). Among the Hemiptera and together with the Nabidae almost all species are terrestrial ambush predators: most other predatory Hemiptera are aquatic. The main exampl ...
s (''Stenolemus bituberus'') hunt web-building spiders by invading the web and plucking the silk to generate vibrations that mimic prey of the spider. This lures the resident spider into striking range of the bug.[Wignall, A.E. and Taylor, P.W., (2010). Assassin bug uses aggressive mimicry to lure spider prey. Proceedings of the Royal Society B. doi:10.1098/rspb.2010.206]
/ref> Spiders from at least five different families routinely invade the webs of other spiders and lure them as prey with vibratory signals (e.g. ''Pholcus
''Pholcus'' is a genus of spiders in the family Pholcidae, with 361 described species as of October 2021.
It includes the cellar spider '' P. phalangioides'', often called the "daddy longlegs". This may cause confusion because the name "daddy ...
'' or ‘daddy long-leg’ spiders; salticid ‘jumping’ spiders from the genera '' Portia'', ''Brettus
''Brettus'' is a genus of jumping spiders. Its six described species are found in southern Asia from India to China and Sulawesi, with a single species endemic to Madagascar.
Two species in this genus, ''B. celebensis'' and ''B. madagascarensis ...
'', ''Cyrba
''Cyrba'' is a genus of spiders in the family Salticidae (jumping spiders). The genus was erected by Hippolyte Lucas in 1846.
Description
''Cyrba'' spiders are small to medium size spiders that are usually brightly colored. Their cephalothora ...
'' and ''Gelotia
''Gelotia'' is a genus of jumping spiders that was first described by Tamerlan Thorell in 1890.
Species
It contains ten species, found only in Asia and on New Britain:
*''Gelotia argenteolimbata'' ( Simon, 1900) – Singapore
*''Gelotia bimacula ...
'').
''Portia fimbriata
''Portia fimbriata'', sometimes called the fringed jumping spider, is a jumping spider (family Salticidae) found in Australia and Southeast Asia. Adult females have bodies 6.8 to 10.5 millimetres long, while those of adult males are 5.2 to ...
'' jumping spiders lure female '' Euryattus'' species by mimicking male courtship vibrations.[Jackson, R.R. and Wilcox, R.S., (1990). Aggressive mimicry, prey-specific predatory behaviour and predator-recognition in the predator–prey interactions of Portia fimbriata and Euryattus sp., jumping spiders from Queensland. Behavioral Ecology and Sociobiology, 26: 111–119. doi:10.1007/BF00171580]
Habitat sensing
The wandering spider (''Cupiennius salei
''Cupiennius salei'', commonly called the tiger bromeliad spider, are large bodied, actively-hunting spiders that are part of the family Trechaleidae. They are found in Central America and Mexico, while other species in the genus are also found i ...
'') can discriminate vibrations created by rain, wind, prey, and potential mates. The creeping grasshopper can escape predation by this spider if it produces vibrations similar enough to those of wind. Thunderstorms and earthquakes produce vibrational cues; these may be used by elephants and birds to attract them to water or avoid earthquakes. Mole rats use reflected, self-generated seismic waves to detect and bypass underground obstacles – a form of "seismic echolocation".
However, this type of use is not considered communication in the strictest sense.
Production of vibrational cues
Vibrational cues can be produced in three ways, through percussion (drumming) on the substrate, vibrations of the body or appendages transmitted to the substrate, or, acoustical waves that couple with the substrate.[O'Connell-Rodwell, C.E., Hart,L.A. and Arnason, B.T., (2001). Exploring the potential use of seismic waves as a communication channel by elephants and other large mammals. American Zoologist, 41(5): 1157–1170. doi]
/ref> The strength of these cues depends mostly on the size and muscular power of the animal producing the signal.[Markl, H., (1983). Vibrational communication. In: ''Neuroethology and Behavioral Physiology,'' edited by Huber, F. and Markl, H. Berlin: Springer-Verlag, pp. 332–353]
; Percussion:
Percussion, or drumming, can produce both short-and long-distance vibrational cues. Direct percussion of the substrate can yield a much stronger signal than an airborne vocalization that couples with the substrate, however, the strength of the percussive cue is related directly to the mass of the animal producing the vibration. Large size is often associated with greater source amplitudes, leading to a greater propagation range. A wide range of vertebrates perform drumming with some part of their body either on the surface or within burrows. Individuals bang heads, rap trunks or tails, stamp or drum with front feet, hind feet or teeth, thump a gular skin, gular pouch, and basically employ available appendages to create vibrations on the substrates where they live. Insects use percussion by drumming (or scraping) with the head, hind legs, fore legs, mid legs, wings, abdomen, gaster, antennae or maxillary palps.
; Tremulation:
Tremulation is performed by a range of insects. This process involves rocking of the entire body with the subsequent vibrations being transferred through the legs to the substrate on which the insect is walking or standing.
; Stridulation:
Insects and other arthropods stridulate
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 mech ...
by rubbing together two parts of the body. These are referred to generically as the stridulatory organs. Vibrations are transmitted to the substrate through the legs or body.
; Tymbal vibrations:
Insects possess tymbal
The tymbal (or timbal) is the corrugated exoskeletal structure used to produce sounds in insects. In male cicadas, the tymbals are membranes in the abdomen, responsible for the characteristic sound produced by the insect. In tiger moths, the t ...
s which are regions of the exoskeleton modified to form a complex membrane with thin, membranous portions and thickened "ribs". These membranes vibrate rapidly, producing audible sound and vibrations that are transmitted to the substrate.
; Acoustically coupled:
Elephants produce low-frequency vocalizations at high amplitudes such that they couple with the ground and travel along the surface of the earth. Direct percussion can produce a much stronger signal than airborne vocalizations that couple with the ground, as shown in the Cape mole rat and the Asian elephant
The Asian elephant (''Elephas maximus''), also known as the Asiatic elephant, is the only living species of the genus ''Elephas'' and is distributed throughout the Indian subcontinent and Southeast Asia, from India in the west, Nepal in the no ...
. However, the power that an animal can couple into the ground at low frequencies is related directly to its mass. Animals of low mass cannot generate low-frequency vibrational surface waves; thus the mole rat could not produce a vibrational signal at 10–20 Hz like the elephant. Some invertebrates e.g. prairie mole cricket ('' Gryllotalpa major''),[Hill, P.S.M. & J.R. Shadley. (2001). Talking back: Sending soil vibration signals to lekking prairie mole cricket males. American Zoologist, 41: 1200–1214] bushcricket (Tettigoniidae
Insects in the family Tettigoniidae are commonly called katydids (especially in North America), or bush crickets. They have previously been known as "long-horned grasshoppers". More than 8,000 species are known. Part of the suborder Ensifera, t ...
),[Kalmring, K., Jatho, M., Rossler, W. and Sickmann, T. (1997). Acousto-vibratory communication in bushcrickets (Orthoptera: Tettigoniidae). Entomology Genetics, 21: 265–291] and cicada
The cicadas () are a superfamily, the Cicadoidea, of insects in the order Hemiptera (true bugs). They are in the suborder Auchenorrhyncha, along with smaller jumping bugs such as leafhoppers and froghoppers. The superfamily is divided into two ...
[Stölting, H., Moore T.E. and Lakes-Harlan. R., (2002). Substrate vibrations during acoustic signalling in the cicada Okanagana rimosa. Journal of Insect Science, 2: 2: 1–7] produce acoustic communications and substrate vibrations that may be due to acoustic coupling.
For acoustic coupling, low-frequency, high-amplitude vocalizations are necessary for long-distance transmission. It has been suggested that other large mammals such as the lion
The lion (''Panthera leo'') is a large Felidae, cat of the genus ''Panthera'' native to Africa and India. It has a muscular, broad-chested body; short, rounded head; round ears; and a hairy tuft at the end of its tail. It is sexually dimorphi ...
and rhinoceros
A rhinoceros (; ; ), commonly abbreviated to rhino, is a member of any of the five extant species (or numerous extinct species) of odd-toed ungulates in the family Rhinocerotidae. (It can also refer to a member of any of the extinct species o ...
may produce acoustically coupled vibrational cues similar to elephants.
Reception of vibrational cues
Vibrational cues are detected by various body parts. Snakes receive signals by sensors in the lower jaw or body, invertebrates by sensors in the legs or body (earthworms), birds by sensors in the legs (pigeons) or bill-tip (shorebirds
245px, A flock of Dunlins and Red knots">Red_knot.html" ;"title="Dunlins and Red knot">Dunlins and Red knots
Waders or shorebirds are birds of the order Charadriiformes commonly found wikt:wade#Etymology 1, wading along shorelines and mudflat ...
, kiwi
Kiwi most commonly refers to:
* Kiwi (bird), a flightless bird native to New Zealand
* Kiwi (nickname), a nickname for New Zealanders
* Kiwifruit, an edible berry
* Kiwi dollar or New Zealand dollar, a unit of currency
Kiwi or KIWI may also ref ...
s and ibis
The ibises () (collective plural ibis; classical plurals ibides and ibes) are a group of long-legged wading birds in the family Threskiornithidae, that inhabit wetlands, forests and plains. "Ibis" derives from the Latin and Ancient Greek word f ...
es), mammals by sensors in the feet or lower jaw (mole rats) and kangaroos by sensors in the legs.[Gregory, J.E., McIntyre, A.K. and Proske, U., (1986). Vibration-evoked responses from lamellated corpuscles in the legs of kangaroos. Experimental Brain Research, 62: 648–653] The star-nosed mole
The star-nosed mole (''Condylura cristata'') is a small semiaquatic mole found in moist, low areas in the northern parts of North America. It is the only extant member of the tribe Condylurini and genus ''Condylura'', and it has more than 25, ...
(''Condylura cristata''), has evolved an elaborate nose structure which may detect seismic waves.[Catania, K.C., (1999). A nose that looks like a hand and acts like an eye: the unusual mechanosensory system of the star-nosed mole. Journal of Comparative Physiology 185: 367–372]
The sensory organs are generically known as somatosensory
In physiology, the somatosensory system is the network of neural structures in the brain and body that produce the perception of touch (haptic perception), as well as temperature (thermoception), body position (proprioception), and pain. It i ...
mechanoreceptors
A mechanoreceptor, also called mechanoceptor, is a sensory receptor that responds to mechanical pressure or distortion. Mechanoreceptors are innervated by sensory neurons that convert mechanical pressure into electrical signals that, in animals, a ...
. In insects these sensors are known as campaniform sensilla
Campaniform sensilla are a class of mechanoreceptors found in insects, which respond to local stress and strain within the animal's cuticle. Campaniform sensilla function as proprioceptors that detect mechanical load as resistance to muscle cont ...
e located near the joints, the subgenual organ
The subgenual organ is an organ in insects that is involved in the perception of sound. The name (Latin ''sub: "''below" and ''genus: "''knee") refers to the location of the organ just below the knee in the tibia of all legs in most insects.
The f ...
in the tibia
The tibia (; ), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outside of the tibia); it connects ...
and 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 ...
located in the antennae. Arachnids use slit sense organ. In vertebrate animals the sensors are Pacinian corpuscles
Pacinian corpuscle or lamellar corpuscle or Vater-Pacini corpuscle; is one of the four major types of mechanoreceptors (specialized nerve ending with adventitious tissue for mechanical sensation) found in mammalian skin. This type of mechanorecept ...
in placental mammals, similar lamellated corpuscles in marsupials, Herbst corpuscles in birds and a variety of encapsulated or naked nerve endings in other animals.
These sensory receivers detect vibrations in the skin and joints, from which they are typically transmitted as nerve impulses (action potentials
An action potential occurs when the membrane potential of a specific cell location rapidly rises and falls. This depolarization then causes adjacent locations to similarly depolarize. Action potentials occur in several types of animal cells, c ...
) to and through spinal nerves to the spinal cord
The spinal cord is a long, thin, tubular structure made up of nervous tissue, which extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column (backbone). The backbone encloses the central canal of the spi ...
and then the brain
A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as vision. It is the most complex organ in a v ...
; in snakes, the nerve impulses could be carried through cranial nerves. Alternatively, the sensory receivers may be centralized in the cochlea
The cochlea is the part of the inner ear involved in hearing. It is a spiral-shaped cavity in the bony labyrinth, in humans making 2.75 turns around its axis, the modiolus. A core component of the cochlea is the Organ of Corti, the sensory org ...
of the inner ear. Vibrations are transmitted from the substrate to the cochlea through the body (bones, fluids, cartilage, etc.) in an ‘extra-tympanic’ pathway that bypasses the eardrum, and sometimes, even the middle ear. Vibrations then project to the brain along with cues from airborne sound received by the eardrum.
Propagation of vibrational cues
Documented cases of vibrational communication are almost exclusively restricted to Rayleigh waves or bending waves. Seismic energy in the form of Rayleigh waves transmits most efficiently between 10 and 40 Hz. This is the range in which elephants may communicate seismically.[Arnason, B.T., Hart, L.A.and O’Connell-Rodwell, C.E., (2002). The properties of geophysical fields and their effects on elephants and other animals. Journal of Comparative Psychology, 116: 123–132] In areas with little to no human-generated seismic noise, frequencies around 20 Hz are relatively noise-free, other than vibrations associated with thunder or earth tremors, making it a reasonably quiet communication channel. Both airborne and vibrational waves are subject to interference and alteration from environmental factors. Factors such as wind and temperature influence airborne sound propagation, whereas propagation of seismic signals are affected by the substrate type and heterogeneity. Airborne sound waves spread spherically rather than cylindrically, attenuate more rapidly (losing 6 dB for every doubling of distance) than ground surface waves such as Rayleigh waves (3 dB loss for every doubling of distance), and thus ground surface waves maintain integrity longer.[O’Connell-Rodwell, E.O., (2007). Keeping an “ear” to the ground: seismic communication in elephants. Physiology, 22: 287–294. doi:10.1152/physiol.00008.20]
/ref> Vibrational signals are probably not very costly to produce for small animals, whereas the generation of air-borne sound is limited by body size.
Benefits and costs of vibrational communication to the signaler are dependent on the function of the signal. For social signaling, daylight and line-of-sight are not required for seismic communication as they are for visual signaling. Likewise, flightless individuals may spend less time locating a potential mate by following the most direct route defined by substrate-borne vibrations, rather than by following sound or chemicals deposited on the path.
Most insects are herbivorous and usually live on plants, therefore the majority of vibrational signals are transmitted through plant stems. Here, communication typically ranges from 0.3 m-2.0 m. It has been suggested that vibrational signals might be adapted to transmit through particular plants.
Insect Mating
Many insects use vibrational communication in mating. In the case of Macrolophus pygmaeus the males produce two different vibrational sounds intentionally while the females produce none. The males produce two different vibrations, a yelp and a roar. The yelps are produced before copulation. Trialeurodes vaporariorum males also use vibrations to communicate during mating. They produce two types of vibrations, a “chirp”, and a “pulse” and occur in different stages throughout the mating ritual. The occurrence of the male signals can change due to male rivalry as well. The frequencies and quality of the vibrational calls can change, for example, a higher quality with lower frequency characterizes an aggressive call. The frequencies can also change to avoid signal overlapping which can lower male responsiveness.
Insect Feeding
The use of vibrational communication for feeding is separated in different areas. Depending on the insect, for example a C. pinguis the process in finding new feeding grounds is quite a process. The little treehoppers have a dance which indicates the need to find a new feeding area, and will communicate through vibrations to send a scout to find the new area. Once this scout has been sent it sends vibrations back to the main group, which then moves over to the new area. There is other evidence that it is seemingly instinctual for insects to follow a path that has vibrations, even if they are artificially created in a lab. Caterpillar larvae also send vibrations that help attract others to their feeding locations. This is done at the same time that they are eating. This type of signal was made by them scraping little hairs on the hind side, which is called anal scraping. Caterpillars do this while eating as they can multitask and share their location with other larvae.
Male-Male Interactions in Insects
Vibrational communication is also used in competition. Macrolophus pygmaeus produces a vibrational sound called a “yelp” that is associated with male-male interactions. The yelp is also associated with physical contact between the two males, and then the males running away while emitting yelps. The duration of the signal as well can affect the female’s response, and it was shown that females typically prefer longer calls. Sometimes insects can tell the fitness of a potential mate by their vibrational signals. The stonefly Pteronarcella badia, uses vibrational communication in mating. The female stonefly can understand the fitness of males that are “duetting” her vibrational signals by timing how long it takes for the male to find her location.
Examples
American alligator
During courtship, male American alligators use American alligator#Vocalizations, their near-infrasound capabilities to bellow to females, assuming a "reverse-arch" posture at the water's surface (head and tail slightly elevated, midsection barely breaking the surface) using near-infrasound to literally make the water's surface "sprinkle" as they bellow, usually termed as their "water dance" during the mating season.
White-lipped frog
One of the earliest reports of vertebrate signaling using vibrational communication is the bimodal system of sexual advertisement of the white-lipped frog (''Leptodactylus albilabris
''Leptodactylus albilabris'' is a species of frog in the family Leptodactylidae. Common names
Its local name is ranita de labio blanco or sapito de labio blanco ("white-lipped froglet") and English name either Gunther's white-lipped frog or Hisp ...
''). Males on the ground sing airborne advertisement songs that target receptive females, but instead of supporting themselves on their front limbs as other frogs often do, they partially bury themselves in soft soil. As they inflate their vocal sacs to produce the airborne call, the gular
Gular is of or pertaining to the throat
In vertebrate anatomy, the throat is the front part of the neck, internally positioned in front of the vertebrae. It contains the pharynx and larynx. An important section of it is the epiglottis, separatin ...
pouch impacts the soil as a ‘thump’ that sets up Rayleigh waves which propagate 3–6 m through the substrate. Advertising males space themselves at distances of 1–2 m, thus, the nearest neighbour males are able to receive and respond to substrate-borne vibrations created by other males.[Lewis, E.R.and Narins, P.M., (1985). Do frogs communicate with seismic
signals? Science, 227: 187–189]
Namib Desert golden mole
Predators may use vibrational communication to detect and capture prey. The Namib Desert golden mole
Golden moles are small insectivorous burrowing mammals endemic to Sub-Saharan Africa. They comprise the family Chrysochloridae and as such they are taxonomically distinct from the true moles, family Talpidae, and other mole-like families, all o ...
(''Eremitalpa granti namibensis'') is a blind mammal whose eyelid
An eyelid is a thin fold of skin that covers and protects an eye. The levator palpebrae superioris muscle retracts the eyelid, exposing the cornea to the outside, giving vision. This can be either voluntarily or involuntarily. The human eyel ...
s fuse early in development. The ear lacks a pinna, the reduced ear opening is hidden under fur and the organization of the middle ear indicates it would be sensitive to vibrational cues. The Namib Desert golden mole actively forages at night by dipping its head and shoulders into the sand in conjunction with ‘sand swimming’ as it navigates in search of termite prey producing head-banging alarms.[Narins, P.M., Lewis, E.R., Jarvis, J.J.U.M. and O’Riain, J., (1997). The use of seismic signals by fossorial southern African mammals: a neuroethological gold mine. Brain Research Bulletin, 44: 641–646][Mason, M.J., (2003). Bone conduction and seismic sensitivity in golden moles (Chrysochloridae). Journal of Zoology, 260: 405–413][Mason, M.J. and Narins, P.M., (2002). Seismic sensitivity in the desert golden mole (Eremitalpa granti): a review. Journal of Comparative Psychology, 116: 158–163] Experimental evidence supports the hypothesis that substrate-borne vibrations produced as wind blows through grassy hummocks influence these moles as they forage on termites associated with the grassy mounds, which are spaced at distances of 20–25 m. The exact mechanism of extracting directional information from the vibrations has not been confirmed.
Elephants
In the late 1990s, Caitlin O'Connell-Rodwell first argued that elephants communicate over long distances using low-pitched rumbles that are barely audible to humans. Further pioneering research in elephant infrasound communication was done by Katy Payne of the Elephant Listening Project and detailed in her book ''Silent Thunder''. This research is helping our understanding of behaviours such as how elephants can find distant potential mates and how social groups are able to coordinate their movements over extensive ranges.[Larom, D., Garstang, M., Payne, K., Raspet, R. and Lindeque, M., (1999). The influence of surface atmospheric conditions on the range and area reached by animal vocalizations. Journal of Experimental Biology, 200: 421–431 rl=http://jeb.biologists.org/cgi/reprint/200/3/421.pdf/ref> Joyce Poole has also begun decoding elephant utterances that have been recorded over many years of observation, hoping to create a lexicon based on a systematic catalogue of elephant sounds.
Seismic energy transmits most efficiently between 10–40 Hz, i.e. in the same range as the fundamental frequency and 2nd harmonic of an elephant rumble. For Asian elephants, these calls have a frequency of 14–24 Hz, with sound pressure levels of 85–90 dB and last 10–15 seconds.] For African elephants, calls range from 15–35 Hz and can be as loud as 117 dB, allowing communication over many kilometers.
It seems that when an elephant rumbles, the infrasound that is produced couples with the surface of the earth and then propagates through the ground. In this way, elephants are able to use seismic vibrations at infrasound frequencies for communication.[Günther, R.H., O'Connell-Rodwell, C.E. and Klemperer, S.L., (2004). Seismic waves from elephant vocalizations: A possible communication mode? Geophysical Research Letters, 31: L11602. doi:10.1029/2004GL019671] These vibrations can be detected by the skin of an elephant's feet and trunk, which relay the resonant vibrations, similar to the skin on a drum. To listen attentively, individuals will lift one foreleg from the ground, possibly triangulating the source, and face the source of the sound. Occasionally, attentive elephants can be seen to lean forward, putting more weight on their front feet. These behaviours presumably increase the ground contact and sensitivity of the legs. Sometimes, the trunk will be laid on the ground.
Elephants possess several adaptations suited for vibratory communication. The cushion pads of the feet contain cartilaginous nodes and have similarities to the acoustic fat (melon
A melon is any of various plants of the family Cucurbitaceae with sweet, edible, and fleshy fruit. The word "melon" can refer to either the plant or specifically to the fruit. Botanically, a melon is a kind of berry, specifically a "pepo". The ...
) found in marine mammals
Marine mammals are aquatic mammals that rely on the ocean and other marine ecosystems for their existence. They include animals such as seals, whales, manatees, sea otters and polar bears. They are an informal group, unified only by their relia ...
like toothed whales
The toothed whales (also called odontocetes, systematic name Odontoceti) are a parvorder of cetaceans that includes dolphins, porpoises, and all other whales possessing teeth, such as the beaked whales and sperm whales. Seventy-three species of t ...
and sirenian
The Sirenia (), commonly referred to as sea-cows or sirenians, are an order of fully aquatic, herbivorous mammals that inhabit swamps, rivers, estuaries, marine wetlands, and coastal marine waters. The Sirenia currently comprise two distinct f ...
s. In addition, the annular muscle surrounding the ear canal
The ear canal (external acoustic meatus, external auditory meatus, EAM) is a pathway running from the outer ear to the middle ear. The adult human ear canal extends from the pinna to the eardrum and is about in length and in diameter.
Struc ...
can constrict the passageway, thereby dampening acoustic signals and allowing the animal to hear more seismic signals.
Elephants appear to use vibrational communication for a number of purposes. An elephant running or mock charging can create seismic signals that can be heard at great distances. Vibrational waveforms produced by locomotion appear to travel at distances of up to while those from vocalizations travel . When detecting the vibrational cues of an alarm call signaling danger from predators, elephants enter a defensive posture and family groups will congregate.[O’Connell-Rodwell, C.E., Wood, J.D., Rodwell, T.C. Puria, S., Partan, S.R., Keefe, R., Shriver, D., Arnason, B.T. and Hart, L.A., (2006). Wild elephant (''Loxodonta africana'') breeding herds respond to artificially transmitted seismic stimuli. Behavioral and Ecological Sociobiology, 59: 842–850. doi:10.1007/s00265-005-0136-2 ] Vibrational cues are also thought to aid their navigation by use of external sources of infrasound. After the 2004 Boxing Day tsunami
An earthquake and a tsunami, known as the Boxing Day Tsunami and, by the scientific community, the Sumatra–Andaman earthquake, occurred at 07:58:53 local time (UTC+07:00, UTC+7) on 26 December 2004, with an epicentre off the west coast of no ...
in Asia, there were reports that trained elephants in Thailand had become agitated and fled to higher ground before the devastating wave struck, thus saving their own lives and those of the tourists riding on their backs. Because earthquakes and tsunamis generate low-frequency waves, O'Connell-Rodwell and other elephant experts have begun to explore the possibility that the Thai elephants were responding to these events.
Tree Hopper
''Calloconophora pinguis,'' use vibrational communication in order to help others of its species find food. They prefer newly growing leaves, and need at least two or more new feeding areas while developing from larvae to adulthood. The C. pinguis use vibrational communication which seems to be a form of running in place and bumping into others on the same stem. Once this occurs a chain reaction follows until one finally leaves to scout another stem, this is similar to honeybees, which have scouts for food locating. Once finding a suitable growing stem for the other C. pinguis larvae, it begins to send short vibrations to the old site. Once the group is together, a similar process occurs again when it runs out of food.
Pill Bug
''Armadillidium officinalis'', these insects are able to use their legs in order to produce stridulations. This allows them to communicate with each other when feeding, looking for other food sources, as well as using their stridulations in means of a mating call. Another reason the pill bugs use their stridulations to communicate is to let others know that there are predators nearby.
Honey Bee
''Apis mellifera'', use vibrational signals called tooting and quacking to communicate. This happens primarily on virgin queen cells when there are multiple queens in the hive. Vibrational signals performed on virgin queens after they emerged from the queen cells are connected to their success in the elimination period.
Mole Cricket
''Gryllotalpa orientalis'', make vibrational cues by scraping the forelegs, tapping the forelegs, pal-pal taps, and tremulation. The functions are unknown but it is known that they are not for mating or sexual selection. ''Gryllotalpa major'' (prairie mole crickets), however, use vibrational cues as one part of their mating call.
"Tok-Tok" Beetle
Psammodes striatus repeatedly taps its abdomen on the ground, sending vibrational cues to communicate with other beetles. In male-female communication, the male typically initiates the tapping. The female responds by tapping as well, and as the communication continues, the female stays in place while the male tries to locate her.
See also
*Animal communication
Animal communication is the transfer of information from one or a group of animals (sender or senders) to one or more other animals (receiver or receivers) that affects the current or future behavior of the receivers. Information may be sent int ...
*Bioacoustics
Bioacoustics is a cross-disciplinary science that combines biology and acoustics. Usually it refers to the investigation of sound production, dispersion and reception in animals (including humans). This involves neurophysiological and anatomical b ...
*Biotremology
Biotremology is the study of production, dispersion and reception of mechanical vibrations by organisms, and their effect on behavior. This involves neurophysiological and anatomical basis of vibration production and detection, and relation of vib ...
*Hearing range
Hearing range describes the range of frequencies that can be heard by humans or other animals, though it can also refer to the range of levels. The human range is commonly given as 20 to 20,000 Hz, although there is considerable variati ...
*Infrasound
Infrasound, sometimes referred to as low status sound, describes sound waves with a frequency below the lower limit of human audibility (generally 20 Hz). Hearing becomes gradually less sensitive as frequency decreases, so for humans to perce ...
*Lateral line
The lateral line, also called the lateral line organ (LLO), is a system of sensory organs found in fish, used to detect movement, vibration, and pressure gradients in the surrounding water. The sensory ability is achieved via modified epithelial ...
*Sense
A sense is a biological system used by an organism for sensation, the process of gathering information about the world through the detection of Stimulus (physiology), stimuli. (For example, in the human body, the brain which is part of the cen ...
References
{{Elephants
Acoustics
Animal communication
Elephants
Ethology
Seismology
Articles containing video clips