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Lampsilis siliquoidea

By Renee Sherman Mulcrone

Geographic Range

The fat mucket is found from the Mississippi River drainage from New York to Minnesota. It occurs south to Arkansas but does not occur from the Tennessee and Cumberland River systems. In the St. Lawrence River system it is found in the Canadian Interior Basin. Lampsilis siliquoidea is also found in Montana and eastern Colorado.

In Michigan L. siliquoidea is found in drainages throughout the state, both in the upper and lower peninsulas. (Burch, 1975)

Habitat

Although found in various substrates and in various habitats from lakes, and headwaters to medium sized rivers, the fat mucket is usually found in quiet water on sandy-mud bottoms. Occasionally it is found in riffles, but usually in waters below riffles, or slowly running water with fine gravel, sand and mud. (Cummings and Mayer, 1992; van der Schalie, 1938; Watters, 1995)

  • Aquatic Biomes
  • rivers and streams

Physical Description

The fat mucket is up to 12.7 cm (5 inches) long , and is oblong to elliptical in shape. The shell thickness is uniform, and may be thin to thick. This species is sexually dimorphic. Depending on habitat, sex, and age, the shell can be compressed or inflated. The anterior end is rounded, the posterior end bluntly pointed in males or truncated in females. The dorsal margin is straight and the ventral margin is straight and may be rounded.

Umbos are broad and raised only slightly above the hinge line. The beak sculpture is fine, with six to ten double-loops.

The periostracum (outer shell layer) is yellow to yellow-brown with green rays. Older specimens tend to be darker and brownish.

On the inner shell, the left valve has two pseudocardinal teeth, which are erect and compressed. The two lateral teeth are thin, short and slightly curved. The right valve has one large, erect pseudocardinal tooth. Anterior to this tooth is a smaller (lamellar) tooth. The one lateral tooth is thin and straight.

The beak cavity is shallow to moderately deep. Although the nacre is white, occasionally it is has a pink or salmon tint and iridescent posteriorly.

In Michigan, this species can be confused with the mucket and pocketbook. The mucket is generally more compressed and slightly more elliptically shaped. The pocketbook is more roundly shaped and has higher umbos. (Cummings and Mayer, 1992; Oesch, 1984; Watters, 1995)

  • Sexual Dimorphism
  • sexes shaped differently
  • Range length
    12.7 (high) cm
    5.00 (high) in

Development

Fertilized eggs are brooded in the marsupia (water tubes) up to 11 months, where they develop into larvae, called glochidia. The glochidia are then released into the water where they must attach to the gill filaments and/or general body surface of the host fish. After attachment, epithelial tissue from the host fish grows over and encapsulates a glochidium, usually within a few hours. The glochidia then metamorphoses into a juvenile mussel within a few days or weeks. After metamorphosis, the juvenile is sloughed off as a free-living organism. Juveniles are found in the substrate where they develop into adults. (Arey, 1921; Lefevre and Curtis, 1910)

Reproduction

Age to sexual maturity for this species is unknown. Unionids are gonochoristic (sexes are separate) and viviparous. The glochidia, which are the larval stage of the mussels, are released live from the female after they are fully developed.

In general, gametogenesis in unionids is initiated by increasing water temperatures. The general life cycle of a unionid, includes open fertilization. Males release sperm into the water, which is taken in by the females through their respiratory current. The eggs are internally fertilized in the suprabranchial chambers, then pass into water tubes of the gills, where they develop into glochidia.

Lampsilis siliquoidea is a long-term brooder, and was gravid from early August to late July in the Huron River, Michigan. It probably breeds in July and early August in Michigan. (Lefevre and Curtis, 1912; van der Schalie, 1938; Watters, 1995)

  • Breeding interval
    The fat mucket breeds once in the warmer months of the year.
  • Breeding season
    In Michigan, the breeding season is probably June to July.
  • Average gestation period
    10 months

Females brood fertilized eggs in their marsupial pouch. The fertilized eggs develop into glochidia. There is no parental investment after the female releases the glochidia.

  • Parental Investment
  • pre-fertilization
    • provisioning
  • pre-hatching/birth
    • provisioning
      • female

Lifespan / Longevity

The age of mussels can be determined by looking at annual rings on the shell. However, no demographic data on this species has been recorded.

Behavior

Mussels in general are rather sedentary, although they may move in response to changing water levels and conditions. Although not thoroughly documented, the mussels may vertically migrate to release glochidia and spawn.

A female Lampsilis siliquoidea has a mantle flap which resembles a minnow or darter. The mimic fish lures its host fish,which chews on the flap and breaks the membrane of the gills. As a result, the fish is infected with glochidia. (Oesch, 1984)

Communication and Perception

The middle lobe of the mantle edge has most of a bivalve's sensory organs. Paired statocysts, which are fluid filled chambers with a solid granule or pellet (a statolity) are in the mussel's foot. The statocysts help the mussel with georeception, or orientation.

Mussels are heterothermic, and therefore are sensitive and responsive to temperature.

Unionids in general may have some form of chemical reception to recognize fish hosts. Mantle flaps in the lampsilines are modified to attract potential fish hosts. While the fat mucket has a fish lure to attract its host fish, if or how it recognizes a specific host is unknown.

Glochidia respond to touch, light and some chemical cues. In general, when touched or a fluid is introduced, they will respond by clamping shut. (Arey, 1921; Brusca and Brusca, 2003; Watters, 1995)

Food Habits

In general, unionids are filter feeders. The mussels use cilia to pump water into the incurrent siphon where food is caught in a mucus lining in the demibranchs. Particles are sorted by the labial palps and then directed to the mouth. Mussels have been cultured on algae, but they may also ingest bacteria, protozoans and other organic particles.

The parasitic glochidial stage absorbs blood and nutrients from hosts after attachment. Mantle cells within the glochidia feed off of the host’s tissue through phagocytocis. (Arey, 1921; Meglitsch and Schram, 1991; Watters, 1995)

Predation

Unionids in general are preyed upon by muskrats, raccoons, minks, otters, and some birds. Juveniles are probably also fed upon by freshwater drum, sheepshead, lake sturgeon, spotted suckers, redhorses, and pumpkinseeds.

Unionid mortality and reproduction is affected by unionicolid mites and monogenic trematodes feeding on gill and mantle tissue. Parasitic chironomid larvae may destroy up to half the mussel gill. (Cummings and Mayer, 1992; Watters, 1995)

Ecosystem Roles

Fish hosts are determined by looking at both lab transformations and natural infestations. Looking at both is necessary, as lab transformations from glochidia to juvenile may occur, but the mussel may not actually infect a particular species in a natural situation. Natural infestations may also be found, but glochidia will attach to almost any fish, including those that are not suitable hosts. Lab transformations involve isolating one particular fish species and introducing glochidia either into the fish tank or directly inoculating the fish gills with glochidia. Tanks are monitored and if juveniles are later found the fish species is considered a suitable host.

The main hosts of Lampsilis siliquoidea are in the family Centrarchidae. Natural infections and glochidial metamorphosis have been observed on bluegill, black crappie, largemouth bass, walleye, white crappie and the yellow perch. Glochidial metamorphosis has also been observed on the longear sunfish, bluntnose minnow, sand shiner, sauger and smallmouth bass. (Coker, et al., 1921; Cummings and Watters, 2004; Howard, 1922; O'Dee and Watters, 2000; Trdan, 1981)

Species Used as Host

Economic Importance for Humans

Economic Importance for Humans: Positive

Mussels are ecological indicators. Their presence in a water body usually indicates good water quality.

Economic Importance for Humans: Negative

There are no significant negative impacts of mussels on humans.

Conservation Status

Lampsilis siliquoidea is currently not listed for conservation status. However, it is commonly found in lakes, where zebra mussels have been thriving.

Other Comments

Lampsilis siliquoidea is synonomous with Lampsilis siliquoidea, and is sometimes called Lampsilis radiata.

Contributors

Renee Sherman Mulcrone (author).

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

detritivore

an animal that mainly eats decomposed plants and/or animals

detritus

particles of organic material from dead and decomposing organisms. Detritus is the result of the activity of decomposers (organisms that decompose organic material).

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

fertilization

union of egg and spermatozoan

filter-feeding

a method of feeding where small food particles are filtered from the surrounding water by various mechanisms. Used mainly by aquatic invertebrates, especially plankton, but also by baleen whales.

freshwater

mainly lives in water that is not salty.

heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

internal fertilization

fertilization takes place within the female's body

metamorphosis

A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

parasite

an organism that obtains nutrients from other organisms in a harmful way that doesn't cause immediate death

phytoplankton

photosynthetic or plant constituent of plankton; mainly unicellular algae. (Compare to zooplankton.)

planktivore

an animal that mainly eats plankton

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

tactile

uses touch to communicate

vibrations

movements of a hard surface that are produced by animals as signals to others

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

References

Arey, L. 1921. An experimental study on glochidia and the factors underlying encystment. J. Exp. Zool., 33: 463-499.

Brusca, R., G. Brusca. 2003. Invertebrates. Sunderland, Massachusetts: Sinauer Associates, Inc..

Burch, J. 1975. Freshwater unionacean clams (Mollusca: Pelecypoda) of North America. Hamburg, Michigan: Malacological Publications.

Coker, R., A. Shira, H. Clark, A. Howard. 1921. Natural history and propagation of fresh-water mussels. Bulletin of the Bureau of Fisheries, 37: 77-181.

Cummings, K., C. Mayer. 1992. Field guide to freshwater mussels of the Midwest. Champaign, Illinois: Illinois Natural History Survey Manual 5. Accessed August 25, 2005 at http://www.inhs.uiuc.edu/cbd/collections/mollusk/fieldguide.html.

Cummings, K., G. Watters. 2004. "Mussel/Host Data Base" (On-line). Molluscs Division of the Museum of Biological Diversity at the Ohio State University. Accessed September 26, 2005 at http://128.146.250.63/Musselhost.

Howard, A. 1922. Experiments in the culture of fresh-water mussels. Bulletin of the Bureau of Fisheries, 38: 63-89.

Lefevre, G., W. Curtis. 1912. Experiments in the artificial propagation of fresh-water mussels. Proc. Internat. Fishery Congress, Washington. Bull. Bur. Fisheries, 28: 617-626.

Lefevre, G., W. Curtis. 1910. Reproduction and parasitism in the Unionidae. J. Expt. Biol., 9: 79-115.

Meglitsch, P., F. Schram. 1991. Invertebrate Zoology, Third Edition. New York, NY: Oxford University Press, Inc.

O'Dee, S., G. Watters. 2000. New or confirmed host identifications for ten freshwater mussels. Captive Care, and Propagation of Freshwater Mussels Symposium,: 77-82.

Oesch, R. 1984. Missouri naiades, a guide to the mussels of Missouri. Jefferson City, Missouri: Missouri Department of Conservation.

Trdan, R. 1981. Reproductive biology of Lampsilis radiata siliquoidea (Pelecypoda: Unionidae). American Midland Naturalist, 106: 243-248.

Watters, G. 1995. A guide to the freshwater mussels of Ohio. Columbus, Ohio: Ohio Department of Natural Resources.

van der Schalie, H. 1938. The naiad fauna of the Huron River, in southeastern Michigan. Miscellaneous Publications of the Museum of Zoology, University of Michigan, 40: 1-83.

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