| Lysmata amboinensis | |
|---|---|
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Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Malacostraca |
| Order: | Decapoda |
| Suborder: | Pleocyemata |
| Infraorder: | Caridea |
| Family: | Lysmatidae |
| Genus: | Lysmata |
| Species: | L. amboinensis |
| Binomial name | |
| Lysmata amboinensis | |
| Synonyms[1] | |
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Lysmata amboinensis is anomnivorousshrimpspecies known by several common names including thePacific cleaner shrimp. It is considered a cleaner shrimp as eatingparasites and dead tissue from fish makes up a large part of its diet.[2][3] The species is a natural part of thecoral reef ecosystem and is widespread across thetropics typically living at depths of 5–40 metres (16–131 ft).[3]
Lysmata amboinensis can reach a body length of 5–6 centimetres (2.0–2.4 in) and have long white antennae. Mature shrimp are pale in colour with longitudinal bands on their carapace; one central white band with wider scarlet red bands on either side. The shrimp has a long larval stage and unusual sexual maturation, initially being male but becoming a functionalhermaphrodite once mature.[2]
Lysmata amboinensis is popular in home and public aquaria where it is commonly referred to as theskunk cleaner shrimp; this is due to its striking colours, peaceful nature, and usefulsymbiotic cleaning relationship which can also be witnessed in captivity.[2]
Adult shrimp can reach a body length of 2.5 to 3 inches with two pairs of long whiteantennae 3-5 inches in length.[citation needed] The body and legs are pale amber in colour with longitudinal bands on thecarapace: one central white band is flanked by wider scarlet red bands. There are several symmetrical white spots on the red tail. The most anterior antennae fork into two making the shrimp appear to have three pairs of antennae. As with alldecapods there are 10 pairs of walking legs, with the most anterior pair having forceps (pincers). Anterior to the walking legs are a pair of whitemaxillipeds used for feeding. Underneath thethorax behind the walking legs are pairedpleopods (swimmerets) used for swimming and brooding eggs.[2]
Lysmata amboinesis have a pair of stalked eyes though experiments suggest they have coarse vision and arecolour blind; this low spatial resolution makes it unlikely they can see the striking patterns of other shrimps or tropical fish.[4]
Lysmata amboinensis is native to coral reefs across thetropics including theRed Sea and theIndo-Pacific Ocean.[3][5] They live on tropicalcoral reefs between depths of 5–40 metres (16–131 ft) and are typically found in caves or reef ledges.[3]
Lysmata amboinesis lay eggs which the adult shrimp keep attached to theirpleopods. The earlylarvae are callednauplii which hatch into more developed larvae called zoeae and go through a free-floatingplanktonic stage. During this time they feed on other plankton andmoult through 14 identified stages growing to approximately 2 centimetres (0.79 in) in length over 5–6 months.[6] At this point the larvae will settle andmetamorphose into a more mature form, though not yet the adult state. This is achieved after several moults which occur every 3–8 weeks.[2][7]
Each shrimp starts out as a male, but after a few moults will become ahermaphrodite allowing them to function as both male and female in interactions with another shrimp; these shrimp have no pure female form.[3] This form of sexual maturation is scientifically described as 'protandric simultaneous hermaphroditism' and is unique toLysmata shrimp amongst other decapod crustaceans.[6][8] In one spawning, adult shrimp will lay between 200–500 eggs which are initially attached to thepleopods and are greenish in colour; the eggs swell and lighten in colour before hatching and a few will turn silver on the day of hatching. The eggs hatch around dusk releasing 3–4 millimetres (0.12–0.16 in) long larvae into the free-floatingpelagic zone.[2]
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Lysmata amboinesis do not live in large groups, more often in pairs, and while omnivorous it is believed they derive much of their nutrition from cleaning parasites and dead tissue from fish. Their mating behaviour has been observed in captivity where it involves little ritual: a pair of fully mature hermaphroditic shrimp will alternate moulting timing, mating occurs shortly following a moult when one shrimp acting as the male will follow the other acting as the female which will brood the fertilised eggs; when the next shrimp moults the roles, and therefore apparent sex, will reverse.[9]
In captivityL. amboinesis have been seen to be socially monogamous showing such aggression that if they are kept in groups of more than 2 individuals one pair will kill the rest. While they are not generally seen in large groups in the wild it is unknown if they are socially monogamous in their natural environment.[10]
Lysmata amboinesis, like other cleaner shrimp, has asymbiotic relationship with 'client' fish in which both organisms benefit; the shrimp gain a meal from eatingparasites living on large fish and the clients benefit from the removal of parasites.[2] Cleaning organisms including shrimp and fish can congregate in one location on a reef in what is called a "cleaning station" which fish will visit when required; cleaning shrimp perform a rocking dance from side to side to signal their services when fish approach.[11] Removal of parasites under captive conditions happens mainly at night though it is unknown whether this is due to shrimp or host fish behaviour.[12] Additionally, cleaning services provided by the shrimp aid wound healing of injured fish supporting the symbiosis hypothesis.[13]L. amboinesis is also commonly found living in caves with their client fish, such as moray eels, providing the shrimp with protection from predators.[14]
Because of the benefits of cleaner shrimp to the fish they clean,Lysmata amboinensis and other species have been suggested as potentially useful to aquaculture.[12]
Lysmata amboinesis was described and named byJohannes Govertus de Man, published in 1888. In the same year it was also described asHippolysmata vittata var. amboinensis listing the shrimp as a variant within the speciesLysmata vittata. These are now considered synonyms withL. amboinesis a distinct species fromL. vittata.[1]
Lysmata amboinesis within the marine aquarium trade is commonly referred to as theskunk cleaner shrimp,white-banded cleaner shrimp orscarlet cleaner shrimp due to its appearance, however this last name is also sometimes used forLysmata debelius.[3][15][16]
Many species ofLysmata, includingL. amboinesis, are commonly kept insalt water aquaria; they are safe and beneficial since they will clean both the tank and fish but not harm corals. For these reasons they are often kept in both home and public aquaria for educational purposes, sometimes in 'touch pools' which allow visitors to put their hand in the water so the shrimp will clean their hand.[2][3][15]
Despite significant effortsL. amboinesis remains difficult to culture in captivity, though adults will regularly spawn eggs. The cycle from spawning to adult form takes approximately 6 months during which time the vast majority of larvae die.[7] As such most shrimps sold in the aquarium industry are wild-caught, this has led to concern about the negative effects of their removal on natural reefs though there is currently no evidence of an effect.[3][17]
Media related toLysmata amboinensis at Wikimedia Commons