Product Code Database
Alpheidae (also known as the snapping shrimp, pistol shrimp, or alpheid shrimp) is a family within the shrimp infraorder Caridea characterized by having asymmetrical claws, the larger of which is typically capable of producing a loud snapping sound.
The family is diverse and worldwide in distribution, consisting of about 1,119 species within 38 or more genera. The two most prominent genera are Alpheus and Synalpheus, with species numbering well over 330 and 160, respectively. Most snapping shrimp dig burrows and are common inhabitants of , submerged seagrass flats, and oyster reefs. While most genera and species are found in tropical and temperate coastal and marine waters, Betaeus inhabits cold seas and Potamalpheops has a cosmopolitan distribution including being found in freshwater caves in Mexico.
When in colonies, the snapping shrimp can interfere with sonar and underwater communication. The shrimp are considered a major source of sound in the ocean.
The claw snaps to create a cavitation bubble that generates acoustic pressures up to at a distance of 4 cm from the claw. As it ejects from the claw, the bubble reaches speeds of . The pressure is high enough to kill small fish. It corresponds to a peak pressure level of 218 decibels relative to one micropascal (dB re 1 μPa), equivalent to a zero to peak source level of 190 dB re 1 μPa m. Au and Banks measured peak-to-peak source levels between 185 and 190 dB re 1 μPa m, depending on the size of the claw. Similar values are reported by Ferguson and Cleary. The duration of the click is less than 1 millisecond.
The snap can also produce sonoluminescence from the collapsing cavitation bubble. As it collapses, the cavitation bubble emits a short flash of light with a broad spectrum. If the light were of thermal origin, a temperature of the emitter over would be required. In comparison, the surface temperature of the Sun is estimated to be around . The light is of lower intensity than the light produced by typical sonoluminescence, and is not visible to the naked eye. It is most likely a byproduct of the shock wave with no biological significance. However, this was the first known instance of an animal producing light by this effect. Subsequently, another group of , the mantis shrimp, has been discovered to contain species whose club-like forelimbs can strike so quickly and with such force as to induce sonoluminescent cavitation bubbles upon impact.
The snapping is used for hunting (hence the alternative name "pistol shrimp"), as well as for communication. When hunting, the shrimp usually lies in an obscured spot, such as a burrow. The shrimp then extends its antennae outwards to determine if any fish are passing by. Once it feels movement, the shrimp inches out of its hiding place, pulls back its claw, and releases a "shot", which stuns the prey; the shrimp then pulls it to the burrow and feeds on it.
Snapping shrimp have the ability to reverse claws. When the snapping claw is lost, the missing limb regenerates into a smaller claw and the original smaller appendage grows into a new snapping claw. Laboratory research has shown that severing the nerve of the snapping claw induces the conversion of the smaller limb into a second snapping claw. The reversal of claw asymmetry in snapping shrimp is thought to be unique in nature.
The snapping shrimp competes with much larger animals, such as the sperm whale and beluga whale, for the title of loudest animal in the sea. When in colonies, the snapping shrimp can interfere with sonar and underwater communication. The shrimp are a major source of noise in the ocean and can interfere with anti-submarine warfare.]
Eusociality behavior has been discovered in the genus Synalpheus. The species Synalpheus regalis lives inside in colonies that can number over 300. All of them are the offspring of a single, large female, the queen, and possibly a single male. The offspring are divided into workers that care for the young and predominantly male soldiers that protect the colony with their huge claws.
The snapping shrimp species retains the same mate after copulation, making them monogamous. Most females of the Alpheidae species are susceptible to mating. Young females become receptive to males either just before (premolt stage) or after the puberty molt, making them physiologically mature and morphologically able to carry the egg mass. Male presence during the molt is beneficial for the female, as searching for a male during her soft-bodied, receptive phase would put her at mortal risk. Mates have more success with partners having greater body mass. The larger shrimp are most successful. These animals practice mate guarding, leading to a decline in mate competition, as well as bonding of partners. The male and female defend their shelter to protect both territory and young. Larvae develop in three stages - nauplius, zoea, and Crustacean larva stages.
|
|
