Ellipsaria lineolata

Geographic Range

Ellipsaria lineolata , the butterfly mussel, is native to the United States and Canada. In the United States, it is found from the midwestern states to the east coast, and south to the Gulf of Mexico. Specifically, it has been recorded in Minnesota, Wisconsin, Iowa, Missouri, Illinois, Indiana, Ohio, Louisiana, Alabama, Mississippi, Georgia, Tennessee, Kentucky, West Virginia and Pennsylvania. It is considered widespread but only locally abundant.

• Biogeographic Regions
• nearctic nearctic
  • native native

Habitat

The butterfly mussel usually inhabits large rivers with swift currents and gravel or sand substrates. It has been found to adapt to life in reservoirs in the southern United States where it can be found in depths up to 6 m or 20 ft.

• Habitat Regions
• temperate temperate
• freshwater freshwater

• Aquatic Biomes
• lakes and ponds
• rivers and streams
• temporary pools

Physical Description

The shell of the butterfly mussel is somewhat triangular with rounded ventral, dorsal and anterior margins. The exterior of the shell has numerous rays and is generally yellowish in color, but older specimens can be brown. The hinge may have a green tint and the interior of the shell is white. The male mussels have a compressed body shape while the females are slightly inflated. The shell of both sexes is thick and females generally measure less than 7 cm while males can reach up to 12.7 cm in length. The beak is turned forward and the beak sculpture consists of a few fine, double-looped lines. This species also has fully developed pseudocardinal and lateral teeth.

• Other Physical Features
• ectothermic ectothermic
• heterothermic heterothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• male larger
• sexes shaped differently

Development

Males release sperm into the water, and the sperm is drawn into the female by the incurrent siphon. Once the eggs are fertilized, the eggs hatch into larvae called glochidia. They remain in the female for about 11 months until the following summer, when they are released and attach to a fish where they develop into juvenile mussels. Known fish hosts for the glochidia of the butterfly mussel include sunfish ( Lepomis spp.), sauger ( Stizostedion canadense ), and drum ( Aplodinotus grunnieus ). While encysted in the fish tissue, they develop into juvenile mussels. Once they have reached this stage, they release from the fish and fall to the riverbed as free-living mussels.

• Development - Life Cycle
• metamorphosis metamorphosis

Reproduction

In late summer, Ellipsaria lineolata males release sperm into the water. The sperm is carried by the current to nearby females, which draw in the sperm through the incurrent siphon.

• Mating System
• polygynandrous (promiscuous) polygynandrous (promiscuous)

Once the eggs are fertilized, they are brooded in the gills of the female. They then develop into larvae called glochidia. Females brood their young long-term (bradytictic) from August to July before releasing them as glochidia. These glochidia then live as parasites by attaching themselves to a fish's gills or fins using their valves. They remain attached until they turn into juvenile mussels at which time they detach from the fish and fall to the riverbed as free-living mussels.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• fertilization fertilization
  • internal internal
• broadcast (group) spawning

Females retain the fertilized eggs and then later the glochidia in a brood pouch for 11 months, from August until July of the following summer. They release the glochidia when a host fish is close, so that the larvae will have a host fish to attach to. Once the glochidia are released, they are independent of the female parent and receive no more care.

• Parental Investment
• female parental care female parental care
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • female

Lifespan/Longevity

While the specific lifespan for Ellipsaria lineolata is unknown, other freshwater mussel species are known to live for many decades and in some cases up to 100 years.

Behavior

Mussels are typically sessile adults unless there is a negative change in the environment causing them to relocate. Juveniles are typically more mobile than adults, using their muscular foot. Freshwater mussels often live in groups with other species of mussels in mussel beds, but they are not social animals and do not interact with each other.

• Key Behaviors
• parasite parasite
• motile motile
• sedentary sedentary
• colonial colonial

Communication and Perception

There is little information available about the communication and perception of Ellipsaria lineolata . Like many freshwater mussels, they likely take cues from their environment, such as water temperature, to initiate spawning and other actions. They can also likely detect changes in light, vibrations, and physical touch. Individuals do not typically communicate to each other.

• Perception Channels
• visual visual
• tactile tactile
• ultrasound ultrasound

Food Habits

Butterfly mussels feed by drawing water in through their incurrent siphon. They then filter the food (bacteria, protozoans, algae, and other organic matter) out of the water. The food particles are then carried into the mouth by cilia that are located on the gills and the remaining water is expelled from the mussel through the excurrent siphon.

• Primary Diet
• herbivore herbivore
  • algivore
• detritivore detritivore

• Plant Foods
• algae
• phytoplankton phytoplankton

• Other Foods
• detritus detritus
• microbes

• Foraging Behavior
• filter-feeding filter-feeding

Predation

Predators of butterfly mussels are mammals such as raccoons, muskrats, and otters. The only protection and defense against predators for Ellipsaria lineolata is its hard shell which protects its soft body. These mussels are also known to burrow into the sediment of the river bottom.

Ecosystem Roles

Butterfly mussels, along with many other species of mussels, filter the water in which they live. This removes many particles from the environment, creating a cleaner system. However, if the water is too polluted, it is unhealthy for the mussels and they are not able to survive in that location. Ellipsaria lineolata serves as prey to a variety of mammals. Larvae are parasites on several fish species, including sunfish ( Lepomis spp.), drum ( Aplodinotus grunnieus ), and sauger ( Stizostedion canadense ).

• Ecosystem Impact
• parasite parasite

Economic Importance for Humans: Positive

Mussels are a sign of a healthy water source. The health of a Ellipsaria lineolata population, as well as examination of individual mussels can provide significant information on the status of an ecosystem. Butterfly mussels are also filter feeders that help purify the water in which they live.

• Positive Impacts
• research and education

Economic Importance for Humans: Negative

There are no known adverse effects of Ellipsaria lineolata on humans.

Conservation Status

Though the IUCN Red List describes Ellipsaria lineolata as being near threatened, it was last changed in 1996 and states that it is in need of updating. Threats to this species are water pollution, industrial discharge, residential discharge, siltation, herbicide and fertilizer run-off, changes to the natural flow of rivers, increased water temperatures, dredging, and invasive species such as zebra mussels . Though the butterfly mussel has not been given an official federal listing, many of the states in its geographic distribution consider it threatened. Due to decreases in populations, it is considered endangered in Ohio and Wisconsin, threatened in Iowa, and a species of special concern in Illinois.

Additional Links

Encyclopedia of Life

BioKIDS Critter Catalog

Contributors

Leslie Schroeder (author), Minnesota State University, Mankato, Robert Sorensen (editor), Minnesota State University, Mankato, Angela Miner (editor), Animal Diversity Web Staff.

References

Coker, R., A. Shira, H. Clark, A. Howard. 1921. Natural history and propagation of fresh-water mussels. Bulletin of the Bureau of Fisheries , 37: 75-181.

Minnesota Department of Natural Resources, 2013. "Species Profile: Ellipsaria lineolata " (On-line). Accessed February 27, 2013 at http://www.dnr.state.mn.us/rsg/profile.html?action=elementDetail&selectedElement=IMBIV13010 .

Suber, T. 1913. Notes on the natural hosts of fresh-water mussels. Bulletin of the Bureau of Fisheries , 32: 101-116.

IUCN Red List of Threatened Species. 1996. " Ellipsaria lineolata " (On-line). Accessed March 24, 2013 at http://www.iucnredlist.org/details/summary/7629/0 .

NaturServe. 2010. " Ellipsaria lineolata " (On-line). Accessed March 26, 2013 at http://www.edulifedesks.org/groups/activity/images?page=4 .

Georgia Museum of Natural History. 2008. "Butterfly mussel" (On-line). Accessed March 24, 2013 at http://naturalhistory.uga.edu/~gmnh/gawildlife/index.php?page=speciespages/ai_species_page&key=elineolata .

Iowa Department of Natural Resources. 2013. "Butterfly- Ellipsaria lineolata " (On-line). Accessed March 24, 2013 at http://www.iowadnr.gov/portals/idnr/uploads/education/Species/mussel/butterfly.pdf .

University of Illinois Board of Trustees. 2013. " Ellipsaria lineolata (Rafinesque, 1820)" (On-line). Accessed March 24, 2013 at http://wwx.inhs.illinois.edu/collections/mollusk/publications/guide/index/106 .