Muelly
Info
Fecampia erythrocephala Giard, 1886
Since Fecampia erythrocephala was first described, no further morphological studies have been conducted on the species. Observations of adult Fecampia erythrocephala in the shrimp Palaemon serratus, a new host for the parasite on the French Atlantic coast, led to elucidation of the morphology of the species and its development in the cocoon.
Morphologically these worms are characteristic. They lack an intestine, have a hermaphrodite reproductive system (morphologically different from other platyhelminths) and a very extensive glandular organ that secretes the cocoon. They are pinkish-salmon colored with a striking crimson head. Only one worm can be found in a cocoon, suggesting that they are self-fertile (Caullery & Mesnil, 1903).
In 1950, Alan Southward wrote that the cocoons of the parasitic worm Fecampia erythrocephala were "probably known by appearance, if not by name, to all coastal collectors" (Southward, 1950).
Spawning observations of the parasite confirm the shrinkage of the flatworm until its complete disappearance. A parasitic influence on the ovaries of the female shrimp was noted. The intermoult cycle is delayed without causing obvious morphological changes, and death of the shrimp does not necessarily follow the exit of Fecampia from the host's body.
Due to its fecundity, this parasite poses a high risk of contamination to shrimp culture in Atlantic and Mediterranean marine conditions.
Cocoons of the parasite are generally abundant on the underside of stones in areas with Fucus vesiculosus, Ascophyllum nodosum, Fucus
Serratus and Laminaria (Laminaria digitata and other Laminaria species). All of these sites were sheltered rocky shores with a mix of bedrock, scree and sand habitats. Algae on larger rocks typically reached 100% coverage below the Fucus vesiculosus zone.
Cocoons were typically located on rocks longer than 10 cm, the undersides of which harbored spirorbid polychaetes, sponges, and encrusting coralline algae. Cocoons and other pollutant organisms were not found on rocks with only green algae on the surface, nor under rocks that were firmly embedded in soft sediment.
Only young shore crabs and shrimps are affected. The maximum size of the affected host was 1.1 cm carapace width. The infestation with this parasitic worm does not depend on the size of the crustaceans. The worms mature quickly in the young crabs. they are thought to have a major impact on crab mortality of young coastal crabs.
Known hosts include Carcinus maenas, Cancer pagurus and Carcinus estuarii. Morphologically similar worms assigned to Fecampia erythrocephala have also been found in hermit crabs (Eupagurus bernhardus, Pilumnus hirtellus, Anapagurus hyndmani) and shrimps (Paleamon serratus), as well as Necora puber, Porcellana platycheles.
The existence of Fecampia erythocephala, which is locally common and brightly colored, has remained almost hidden from science; probably because very young, small crabs were almost never examined by parasitologists. Ironically, the abundance of cocoons in some parts of the intertidal zone makes their local occurrence easier to determine than almost any other crab parasite. The key to their discovery lies in the ability of field ecologists to recognize the cocoons as a free-living life stage of a crab parasite.
Since Fecampia erythrocephala was first described, no further morphological studies have been conducted on the species. Observations of adult Fecampia erythrocephala in the shrimp Palaemon serratus, a new host for the parasite on the French Atlantic coast, led to elucidation of the morphology of the species and its development in the cocoon.
Morphologically these worms are characteristic. They lack an intestine, have a hermaphrodite reproductive system (morphologically different from other platyhelminths) and a very extensive glandular organ that secretes the cocoon. They are pinkish-salmon colored with a striking crimson head. Only one worm can be found in a cocoon, suggesting that they are self-fertile (Caullery & Mesnil, 1903).
In 1950, Alan Southward wrote that the cocoons of the parasitic worm Fecampia erythrocephala were "probably known by appearance, if not by name, to all coastal collectors" (Southward, 1950).
Spawning observations of the parasite confirm the shrinkage of the flatworm until its complete disappearance. A parasitic influence on the ovaries of the female shrimp was noted. The intermoult cycle is delayed without causing obvious morphological changes, and death of the shrimp does not necessarily follow the exit of Fecampia from the host's body.
Due to its fecundity, this parasite poses a high risk of contamination to shrimp culture in Atlantic and Mediterranean marine conditions.
Cocoons of the parasite are generally abundant on the underside of stones in areas with Fucus vesiculosus, Ascophyllum nodosum, Fucus
Serratus and Laminaria (Laminaria digitata and other Laminaria species). All of these sites were sheltered rocky shores with a mix of bedrock, scree and sand habitats. Algae on larger rocks typically reached 100% coverage below the Fucus vesiculosus zone.
Cocoons were typically located on rocks longer than 10 cm, the undersides of which harbored spirorbid polychaetes, sponges, and encrusting coralline algae. Cocoons and other pollutant organisms were not found on rocks with only green algae on the surface, nor under rocks that were firmly embedded in soft sediment.
Only young shore crabs and shrimps are affected. The maximum size of the affected host was 1.1 cm carapace width. The infestation with this parasitic worm does not depend on the size of the crustaceans. The worms mature quickly in the young crabs. they are thought to have a major impact on crab mortality of young coastal crabs.
Known hosts include Carcinus maenas, Cancer pagurus and Carcinus estuarii. Morphologically similar worms assigned to Fecampia erythrocephala have also been found in hermit crabs (Eupagurus bernhardus, Pilumnus hirtellus, Anapagurus hyndmani) and shrimps (Paleamon serratus), as well as Necora puber, Porcellana platycheles.
The existence of Fecampia erythocephala, which is locally common and brightly colored, has remained almost hidden from science; probably because very young, small crabs were almost never examined by parasitologists. Ironically, the abundance of cocoons in some parts of the intertidal zone makes their local occurrence easier to determine than almost any other crab parasite. The key to their discovery lies in the ability of field ecologists to recognize the cocoons as a free-living life stage of a crab parasite.
