Glochidia


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Glochidia

 

the parasitic larvae of freshwater bottom mollusks—Lamellibranchia—of the family Unionidae. Glochidia have bivalve triangular shells, which close by means of single, contracting muscles. The edge of each valve usually has a serrated spine. The foot is undeveloped and is equipped with a long adhesive byssal thread—the lasso. The intestines are reduced. In the early stages of their development glochidia enter the, gills of a host specimen, where they lay eggs. In the spring, with the aid of the spines and the lasso, they attach themselves to the gills and skin of fish. In this manner glochidia spread through a body of water and move against river currents. After metamorphosis, the mollusk drops to the bottom. Glochidia cause no particular damage to fish.

V. A. SVESHNIKOV

References in periodicals archive ?
Case study: sensitivity of mussel glochidia and regulatory test organisms to mercury and a reference toxicant.
A museum voucher of this species from the Calamus Reservoir in the Loup Basin probably represents a recent colonization via glochidia infected fish.
Although the underlying basis for host specificity and host resistance to glochidia are largely unknown, local tissue reactions of the host are likely important in mediating these responses (Arey, 1921; Meyers and Millemann, 1977; Fustish and Millemann, 1978; Meyers et al.
Glochidia attach themselves to the gills of young fish from the salmon family that carry them back upstream.
The odds against any one individual glochidium surviving are extremely large--thousands or millions of glochidia may be produced, but the vast majority never encounter a fish.
These massulae cling to the megaspores by filamentous structures known as glochidia (except in the case of A.
However while not examined in the present study a negative effect of increased salinity on glochidia production has been observed (Blakeslee et al.
Glochidia ydi'r enw ar y larfau bach yma ac maen nhw'n ddigon tebyg i gregyn gleision bychan.
Copepod parasites of fresh-water fishes and their economic relations to mussel glochidia.
The mussels were placed into in-stream holding cages so that they could easily be retrieved the following spring, when fertile females would likely be gravid, or carrying mature larval mussels called glochidia.