Antibody response of bluegill sunfish during development of acquired resistance against the larvae of the freshwater mussel Utterbackia imbecillis.

The larvae of freshwater mussels in the order Unionoida are obligate parasites on fishes, on which they metamorphose into juveniles. Bluegill sunfish (Lepomis macrochirus) acquire resistance against glochidia of the freshwater mussel Utterbackia imbecillis after 2 infections. In order to study the systemic and mucosal antibody response associated with acquired resistance, sera from experimentally infected fish were collected at 10-d intervals during 4 sequential infection periods and from naïve fish.

Persistence of host response against glochidia larvae in Micropterus salmoides.

Host fish acquire resistance to the parasitic larvae (glochidia) of freshwater mussels (Unionidae). Glochidia metamorphose into juvenile mussels while encysted on host fish. We investigated the duration of acquired resistance of largemouth bass, Micropterus salmoides (Lacepède, 1802) to glochidia of the broken rays mussel, Lampsilis reeveiana (Call, 1887).

Encapsulation of attached ectoparasitic glochidia larvae of freshwater mussels by epithelial tissue on fins of naive and resistant host fish.

To metamorphose into juveniles and subsequently mature into adults, the glochidia larvae of freshwater mussels in the order Unionoida must temporarily parasitize the gills, fins, or other external structures of fish. Once attached to the fish, the glochidium is encapsulated by host fish epithelial tissue. The migration of epithelial cells of the bluegill sunfish Lepomis macrochirus over glochidia of Utterbackia imbecillis was examined by time-lapse video microscopy, and the morphology was examined by scanning electron microscopy.

Cross-resistance of largemouth bass to glochidia of unionid mussels.

We tested whether host fish that acquired resistance to glochidia of one mussel species were cross-resistant to glochidia of other species. Largemouth bass (Micropterus salmoides) were primed with 4-5 successive infections of glochidia of Lampsilis reeveiana. The percentage of attached glochidia that survived and transformed to the juvenile stage (transformation success) was compared between primed fish and naïve controls.

Acquired resistance of bluegill sunfish Lepomis macrochirus to glochidia larvae of the freshwater mussel Utterbackia imbecillis (Bivalvia: Unionidae) after multiple infections.

The effects of multiple infections on the host-parasite relationship between bluegill sunfish (Lepomis macrochirus) and parasitic glochidial larvae of the freshwater mussel Utterbackia imbecillis were examined. Naïve, young-of-the-year bluegills were infected with glochidia and placed in individual observation chambers. Each day, water was drained from each chamber and the numbers of dead glochidia, live glochidia, partially metamorphosed glochidia, and fully metamorphosed juvenile mussels were counted.

Behavioral aspects of host recognition by the symbiotic water mite Unionicola formosa (Acarina, Unionicolidae).

The occurrence and specificity of host recognition behavior of adult and nymphal Unionicola formosa and the capability of adult mites to recolonize various mussel species were examined. Adult U. formosa aggregated on excised tissue from their host mussel, Anodonta imbecilis, in preference to that of two other species of mussels.