Cocoon deposition on three crab species and fish parasitism by the leech Notostomum cyclostoma from deep fjords in northern British Columbia

Abstract

Cocoons of the sanguivorous piscicolid leech Notostomum cyclostoma (Johansson) were found on 3 crab species, Lithodes aequispina, Paralithodes camtschatica and Chionoecetes bairdifrom deep fjords in the Portland Inlet system, northern British Columbia, Canada. This leech-crab association is convenient for cocoon deposition and dispersal. The leech does not appear to harm its crab hosts. Gut contents of N. cyclostoma collected off the crabs were fish-blood meals in various stages of digestion. The haemoflagellate Cryptobia sp. was observed in gut and proboscis area of 90 % of the leeches. One leech harbored another haemoflagellate, Trypanosoma sp., in its gut. Cryptobia sp. and Trypanosoma sp. were observed in the blood of 29 % of yellowfin soles Limanda aspera from one fjord. No haemoflagellates were observed in 7 other fish species caught coincidentally with the crabs. L. aequispina was the most cocoon -infested crab species. In Observatory Inlet, where L. aequispina was least common, more cocoons per crab were recorded than from the other fjords, Alice and Hastings Arms. Crabs which had not moulted for some time carried more cocoons than those with newer shells. This was less marked among C. bairdi subject to the exoskeleton disease of Black Mat Syndrome on older shells. The most used cocoon deposition site on crabs was the carapace, followed by the merus segments of the posterior limbs.

Freshwater mussels house a diverse mussel-associated leech assemblage

“…Association of Alboglossiphonia leeches with freshwater bryozoans recorded in Siberia is another unusual example, illustrating a rather “clandestine shelter” commensalism than a host-parasite relationship 50 . In soft-bottom environments, the marine leech Notostomum cyclostomum (Piscicolidae) uses crab exoskeletons as the hard substrate for its cocoon, but this leech species does not feed on crustaceans but on fish blood 51 . These examples highlight that leeches use various invertebrate taxa as hosts, shelters or brooding substrates and that such hidden associations of Hirudinea with other animal groups may be much more common than it was assumed previously.…”

Affiliations between bacteria and marine fish leeches (Piscicolidae), with emphasis on a deep‐sea species from Monterey Canyon, CA

“…octopus and urchins) and inanimate. Both J. arctica and G. antarctica have been observed to move between invertebrates (octopuses, urchins and pycnogonids) and their actual fish prey (Janssen, 1993) and other well‐known species, such as Notostomum and Megaliobdella spp., have often been collected separately from prey animals (Sloan et al ., 1984; Utevsky et al ., 2007), as was the case for the deep‐sea leech examined in this study.…”

Phoretic interaction between the kangaroo leech Marsupiobdella africana (Hirudinea: Glossiphoniidae) and the cape river crab Potamonautes perlatus (Decapoda: Potamonautidae)

“…Embryos are transferred externally to the brood pouch where up to 50 young develop over a period of up to 4 weeks. If the leech makes contact with a Xenopus , the young are discharged explosively on the surface of the host ( Van Der Lande and Tinsley, 1976 ).The second adaptive trend involves the deposition of encapsulated eggs by the parental leech on the shells of arthropods and is described as a temporary and life stage specific phoretic strategy to protect the eggs from predation by snails ( Sawyer, 1971; Sloan et al, 1984 ). Leech parental care evolved further from the direct protection of the cocoon by the parental body towards advanced stages of brooding behavior ( Sawyer, 1971; Kutschera and Writz, 2001 ).…”