Parasitism is one of several classes of symbiosis. A parasitic relationship is a non- mutual relationship between two organisms. One organism, the parasite, lives off another organism, the host. The parasite typically attacks one host and does not kill the host. However, a parasitoid is another parasitic relationship where there is one host and the host is always killed. Sacculina is a genus of parasitic rhizocephalan barnacles that infect and castrate crabs. This genus was first described by Italian marine biologist Felipe Cavolini in 1786 (Day, 1935). There are many species within the genus Sacculina , including Sacculina carcini. The species, Sacculina carcini is a high specialized parasite that infects and castrates crabs. The specific
…show more content…
Having a direct life cycle means that there are no intermediate host. Sacculina carcini also does not have any vectors in its life cycle. The life cycle of Sacculina carcini beings with a nauplius larvae being emitted from the mantle cavity of the host crab. The novel, Parasite Rex describes the nauplius to appear like ..."teardrops equipped with fluttering legs and a pair of dark eyespots" (Zimmer, 2000). The nauplius larvae is free living in the water and will undergo several molts with the last molt revealing the cypris stage (Day, 1935). The cypris larve enters into its infective stage after three days. The female cypris has "...sense organs on her legs that can catch the scent of the host" (Zimmer, 2000). The cypris will then attach to the body of the crab through a antenna. The larva will shed its body and become a mass of cells which then infiltrates the crabs body through the antenna. The mass of cells migrate to the mid-gut of the crab, where tendril like looks will spread across the crab's organs and will start to absorb nutrients from the crab (Day, 1935). The host crab is unable to fight off the infection from Sacculina and can go "...its entire life with the parasite filling its entire body, the roots even wrapping around its eyestalks" (Zimmer, 2000). After several weeks, the parasite will develop a reproductive sac known as the virgin externae. This structure contains …show more content…
The Green crab is native to the north-east Atlantic Ocean and Baltic Sea, around the upper European/ North African coast. However, the Green crab has become an invasive species and has spread to areas such as South Africa, Australia, Japan, and both coasts of North America. With the increasing geographic range of the host, Sacculina has also extended its range and can be found in those new areas as well. The invasive crab has had serious impacts on fisheries as the crab continues to eat extensive amounts of oysters, mussels, and other crabs. Introduction of Sacculina to areas with a high prevalence of Carcinus maenas could bring about economical impacts. Knowing what kind of effects the parasite has on its host, "... sterilisation effect of parasites resulting from the alteration of morphological characters and hormonal levels reduce overall reproduction rates, therefore lowering population densities over time" (Waiho, Fazhan, Glenner, & Ikhwanuddin, 2017). This could prove as a positive economic effect for areas that are high infested. However, if left unattended, Sacculina may end up wiping out almost all of the Green crabs in the area throwing off the ecological balance again. A decrease in the crab population may also have a negative economic effect for areas that rely on the Green crab as a food source or rely on the crab as a source of
Having a direct life cycle means that there are no intermediate host. Sacculina carcini also does not have any vectors in its life cycle. The life cycle of Sacculina carcini beings with a nauplius larvae being emitted from the mantle cavity of the host crab. The novel, Parasite Rex describes the nauplius to appear like ..."teardrops equipped with fluttering legs and a pair of dark eyespots" (Zimmer, 2000). The nauplius larvae is free living in the water and will undergo several molts with the last molt revealing the cypris stage (Day, 1935). The cypris larve enters into its infective stage after three days. The female cypris has "...sense organs on her legs that can catch the scent of the host" (Zimmer, 2000). The cypris will then attach to the body of the crab through a antenna. The larva will shed its body and become a mass of cells which then infiltrates the crabs body through the antenna. The mass of cells migrate to the mid-gut of the crab, where tendril like looks will spread across the crab's organs and will start to absorb nutrients from the crab (Day, 1935). The host crab is unable to fight off the infection from Sacculina and can go "...its entire life with the parasite filling its entire body, the roots even wrapping around its eyestalks" (Zimmer, 2000). After several weeks, the parasite will develop a reproductive sac known as the virgin externae. This structure contains …show more content…
The Green crab is native to the north-east Atlantic Ocean and Baltic Sea, around the upper European/ North African coast. However, the Green crab has become an invasive species and has spread to areas such as South Africa, Australia, Japan, and both coasts of North America. With the increasing geographic range of the host, Sacculina has also extended its range and can be found in those new areas as well. The invasive crab has had serious impacts on fisheries as the crab continues to eat extensive amounts of oysters, mussels, and other crabs. Introduction of Sacculina to areas with a high prevalence of Carcinus maenas could bring about economical impacts. Knowing what kind of effects the parasite has on its host, "... sterilisation effect of parasites resulting from the alteration of morphological characters and hormonal levels reduce overall reproduction rates, therefore lowering population densities over time" (Waiho, Fazhan, Glenner, & Ikhwanuddin, 2017). This could prove as a positive economic effect for areas that are high infested. However, if left unattended, Sacculina may end up wiping out almost all of the Green crabs in the area throwing off the ecological balance again. A decrease in the crab population may also have a negative economic effect for areas that rely on the Green crab as a food source or rely on the crab as a source of