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 ?
The mussels are then taken to Genoa, where they are held until the glochidia are expelled.
The solution was stirred until a homogeneous mixture of glochidia was attained.
Another complicating factor is many of the host fishes required for glochidia transformation are not commonly propagated.
However, based on field observations of the number of gravid females releasing glochidia each year in the spring (J.
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.
The structure of glochidia was observed by immersing dry microsporangia in water:ethanol:glycerol (1:1:1) solution for 24 hours.
Released from the gills of an adult mussel into the water no bigger than grains of sand, the glochidia require a host for the several weeks it takes them to metamorphose into tiny mussels able to live on their own.
fluminea has negatively impacted the already rapidly declining native bivalves by depleting food resources, reducing habitat space and reducing bivalve reproduction by ingesting large numbers of unionid sperm, glochidia, and newly formed juveniles (Strayer 1999).
The transformation of glochidia to juvenile mussel occurs largely during the parasitic period.
triquetra (Zanatta and Murphy, 2008 and references therein), and the mussel has evolved a unique strategy of capturing the fish to infest it with glochidia (Barnhart et al.
imbecillis does not depend on parasitism (It carries the young in its marsupia during metamorphosis from glochidia to juvenile mussels, thus eliminating the parasitic stage on fishes which other species undergo) and it is hermaphroditic.