Livoneca redmanii Leach 1818

Crustaceans have various sensory resceptors, mainly setae over the body. Photoreceptors are also generally present.

Communication Channels: tactile ; chemical

Perception Channels: tactile ; chemical

Livoneca redmanii seems to be in no immediate danger because its type of hosts are abundant.

US Federal List: no special status

As a species in the family Cymothoidae, Livoneca redmanii is likely a protandrous, hermaphroditic gill parasite. Free living planktonic larva can remain free-swimming for a restricted amount of time without a host, about 1-2 weeks. They may alternate between parasitic and free-living stages during the transition to functional male stages. Early in life it is a parasitic male within the gill chamber of the host fish. Later it transforms into a female, which can bear free living young in the marsupium, while still in the gill chamber. The exact stimulus initiating the sex change is not clear. It may be the presence of a new male entering the gill chamber. Due to the varying sizes of females and males, it appears that the male will undergo the sex change molt when a second male attempts to establish on the same host. Nevertheless, studies have shown that sex change does happen under neuroendocrine control.

Although Livoneca redmanii parasitizes fish which are economically important to humans, there seems to be no negative impact because the damage to these fish is so little.

There are no known benefits for humans.

Livoneca redmanii commonly parasitizes Pomatomus saltatrix (bluefish), Morone saxatilis (striped bass), and Birdiella chrysura (silver perch).

Ecosystem Impact: parasite

Species Used as Host:

• Pomatomus saltatrix
• Morone saxatilis
• Birdiella chrysura

The parasitic isopod is mainly found within the gill chamber between the operculum and the gills, where it feeds on tissue. Although inhabiting the gill chamber and closely associated with the host's blood, Livoneca redmanii does not feed on the blood.

Animal Foods: body fluids

Primary Diet: carnivore (Eats body fluids)

Livoneca redmanii is distributed along the Atlantic and Gulf coasts of the United States, ranging from Wood Holes, Massachusetts to the Mississippi River.

Biogeographic Regions: atlantic ocean (Native )

Livoneca redmanii is found in aquatic environments on marine fish along coastal areas, specifically in the Atlantic coast and Gulf of Mexico. It commonly parasitizes Pomatomus saltatrix (bluefish), Morone saxatilis (striped bass), and Birdiella chrysura (silver perch).

Habitat Regions: saltwater or marine

Aquatic Biomes: coastal

Other Habitat Features: intertidal or littoral

Livoneca redmanii is generally light brown with black chromatophores throughout life. This parasite has an ovate body, with an average width of 13 mm and an average length of 21 mm. The head is as wide as long, usually 3 mm, and has indistinct eyes situated post-laterally and two pairs of antennae. The first pair of antennae are separated by 1 mm and are composed of six to seven articles, whereas the second pair have eight to nine articles. The thorax contains seven segments. The first five are each about 2 mm and the last two are about 1 1/2 mm. The abdomen is not set in the thorax. It is slightly narrower than the thorax and has six segments, which gradually decrease in width. The uropoda are equal in length. The inner branch is larger than the outer one by about one half. The legs, which are the most pertinent feature for this parasite's lifestyle, have curved dactyli for grasping on to the fish.

Average length: 21 mm.

Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry

This species is probably consumed by fish in its free-living stages. Mortality for early stages are high due to not reaching a suitable host.

As a species in the family Cymothoidae, Livoneca redmanii is likely a protandrous, hermaphroditic gill parasite. Free living planktonic larva can remain free-swimming for a restricted amount of time without a host, about 1-2 weeks. They may alternate between parasitic and free-living stages during the transition to functional male stages. Early in life it is a parasitic male within the gill chamber of the host fish. Later it transforms into a female, which can bear free living young in the marsupium, while still in the gill chamber. The number of eggs carried in the marsupium varies directly with body length, ranging from 300-600. The hatching eggs are released via the gill chamber and opercular opening of the host.

The exact stimulus initiating the sex change is not clear. It may be the presence of a new male entering the gill chamber. Due to the varying sizes of females and males, it appears that the male will undergo the sex change molt when a second male attempts to establish on the same host. Nevertheless, studies have shown that sex change does happen under neuroendocrine control.

Key Reproductive Features: sequential hermaphrodite (Protandrous ); sexual

Parental Investment: pre-fertilization (Provisioning)

Livoneca redmanii là một loài chân đều trong họ Cymothoidae. Loài này được Leach miêu tả khoa học năm 1818.