Egg‐feeding in the freshwater piscicolid leech Cystobranchus virginicus (Annelida, Hirudinea)

Abstract

Abstract. Leeches are common terrestrial and aquatic annelids, parasitizing or feeding on a wide range of host taxa. Here we report evidence for an unusual feeding behavior of egg‐feeding in the piscicolid leech Cystobranchus virginicus. We identified distended specimens of C. virginicus in the nests of at least 4 different fish species: Campostoma anomalum, Moxostoma carinatum, Moxostoma sp. (either M. anisurum and/or M. breviceps), and Nocomis leptocephalus. We collected a total of 41 leeches from the nests of these host species and documented at least 1 leech in 19 of 55 nests (35%), with many sites containing multiple leeches. Individuals of C. virginicus were not identified feeding on any of the 41 adult specimens of Moxostoma spp. or the 635 adult specimens of Nocomis leptocephalus examined, and were never found in the absence of active host spawning (26 sites). These results are consistent with individuals of C. virginicus being an opportunistic or possibly even an obligate egg‐feeder, potentially timing their own reproductive activities with the spawning of their fish hosts. The current distribution of C. virginicus has been expanded to include North Carolina, South Carolina, and Tennessee. The potential for leech species to induce mortality in developing fish eggs could be a concern for fish conservation and merits further investigation.

Mutualism or parasitism: Partner abundance affects host fitness in a fish reproductive interaction

“…; Dorn & Wojdak, 2004;Eversole, 2014), juvenile salamanders (Plethodontidae: Desmognathus and Eurycea spp. ; Blaustein, Sadeh, & Blaustein, 2014;Parker, 1994), and various other predacious invertebrates that have been observed burrowing in chub nests in previous studies (Light, Fiumera, & Porter, 2005;Swartwout, Keating, & Frimpong, 2016) as well as the present one. Manipulating abundance of these egg predators was not feasible, and we assumed equal effects of these taxa across EUs.…”

First freshwater mussel-associated piscicolid leech from East Asia

“…Freshwater piscicolid leeches are known to feed on fish blood almost exclusively 9 , 19 , while one species ( Gonimosobdella virginica comb. nov. ) was found to be a possible obligate egg feeder in nests of four fish taxa 20 . Conversely, the marine Piscicolidae share a much broader host range, with numerous species being associated with vertebrate and invertebrate taxa such as fishes, turtles, crustaceans, pycnogonids, and octopuses 7 , 21 – 24 .…”

Unexpected Discovery of an Ectoparasitic Invasion First Detected in the Baikal Coregonid Fish Population

“…Primarily, the fact that leeches were found on fish in the spawning grounds may suggest that they feed on omul eggs and accidentally fall onto the fish. Moreover, there is much evidence about the feeding of leeches on the eggs of fish and amphibians (e.g., [19,61]), but this feeding strategy is rare and has been often omitted entirely in reviews about leeches. However, the infection of pink salmon eggs (Oncorhynchus gorbuscha (Walbaum, 1792)) with freshwater leeches (Cystobranchus salmositicus) has long been reported [62].…”