Limulus polyphemus
(Schaul 2010)
Outline
 Horseshoe Crab Overview
 Background
 Physical features
 Reproduction

Nest Sites
 Life cycle
 Endangered?
 Why care?
 Important ecologically for migratory birds
 Production of LAL
 Bait for commercial harvesting of whelk and eel
 Future Research?
Background
 Phylum Arthropoda
 Dates from Cambrian period
 Habitat
(Chernoff 2011)
 shallow water along North American Atlantic
coast
 Swims with abdominal plates
 Walks with walking legs
 Feed at night – worms & small mollusks
Physical Features
Dorsal View
Ventral View
(Skytitles 2010)
(CCCMKC 2005)
Reproduction
 Needed:
 High tide
 Spring/summer season
 Sexually mature female
and male(s)
(Query 2008)
 Process:
 Female buries eggs into
sand
 External fertilization
Reproduction:
Who’s the Daddy?
(Brockmann et al. 1994)
Low Tide
(ERDG 2009)
Nest Sites
 Location, location, location!
 Just above mean high tide line
 Sandy beaches
 Sloped beaches
(ERDG 2009)
Nest Sites- Slope Study
(Botton & Loveland 1987)
 Sloped beaches vs. Flat beaches
 Similar beaches, except degree of slope
 4,300 total stranded horseshoe crabs
 20-25% of stranded from sloped beach
 Blinded/Partially blinded HsC
 Similar data
Nest Sites- Distance up beach
(Penn & Brockmann 1994)
(Penn & Brockmann 1994)
Nest Sites- Tide Depth/Time
(Penn & Brockmann 1994)
Life Cycle
(Penn & Brockman 1994)
 Egg
 2 to 4 weeks
 Trilobite larvae
 2 weeks
 Juvenile
 up to 10 years
 Adult
 19 year life span average
(ERDG 2009)
(Query 2008)
Endangered?
 Population numbers decreasing
 Natural threats



Maturation duration
Dangers during mating
Egg/larval mortality
 Harvesting



Biomedical research & companies
Scientific research
Bait for fisheries
Why Care?

Important ecologically for migratory birds
 Production of LAL
 Bait for commercial harvesting of whelk and
eel
 $ Economy $
(Rizzardi 2009)
(Breese 2009)
(Karpanty et al. 2006)
Limulus Amoebocyte Lysate (LAL)
(Blackfang 2011)
(Charles River Laboratories2011)
Further Research
 Population structure
 Sex structure
 Limited studies
 Confined to Delaware
Bay
 Most research on
spawning populations
(Volz 2008)
Literature Cited
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Botton, M. L. & R. E. Loveland. 1987. Orientation of the horseshoe crab, Limulus Polyphemus, on a sandy beach.
Biological Bulletin 173(2):289-298.
Brockmann, H.J. 1990. Mating behavior of horseshoe crabs, Limulus polyphemus. Behaviour 114(1/4):206-220.
Brockmann, H.J., T. Colson, W. Potts. 1994. Sperm competition in horseshoe crabs (Limulus polyphemus).
Behavioral Ecology and Sociobiology 35(3):153-160.
Coursey, Y., N. Ahmad, B.M. McGee, N. Steimel, M. Kimble. 2003. Amebocyte production begins at stage 18
during embryogenesis in Limulus polyphemus. Biological Bulletin 204(1):21-27.
DNR. 2005. Horseshoe crabs: a living fossil. Maryland Departments of Natural Resources. Available:
http://www.dnr.state.md.us/education/horseshoecrab/. (June 2011).
Hickman, C.P., L.S. Roberts, S.L. Keen, A. Larson, D.J. Eisenhour. 2007. Animal diversity, 4th Edition. McGraw
Hill, Boston.
Karpanty, S. M., J.D. Fraser, J. Berkson, L. J. Niles, A. Dey, E.P. Smith. 2006. Horseshoe crab eggs determine red
knot distribution in Delaware Bay. The Journal of Wildlife Management 70(6):1704-1710.
Penn, D. & H.J. Brockmann. 1994. Nest-site selection in the horseshoe crab, Limulus polyphemus. Biological
Bulletin 187(3):373-384.
Rizzardi, K. 2009. With red knots on the candidate list, third circuit declares emergency listing dispute moot.
ESA BLAWG. Available: http://www.esablawg.com/esalaw/ESBlawg.nsf/d6plinks/KRII-7QA2EU. (June 2011).
Rutecki, D., R.H. Carmichael, I. Valiela. 2004. Magnitude of harvest of Atlantic horseshoe crabs, Limulus
polyphemus, in Pleasant Bay, Massachusetts. Estuaries 27(2):179-187.
Sekiguchi, K., H. Seshimo, H. Sugita. 1988. Post-embryonic development of the horseshoe crab. Biological
Bulletin 174(3):337-345
Smith, D.R., P.S. Pooler, R.E. Loveland, M.L. Botton, S.F. Michels, R.G. Weber, D.B. Carter. 2002. Horseshoe crab
(Limulus polyphemus) reproductive activity on Delaware Bay beaches: interactions with beach characteristics.
Graphics Cited
 Blackfang. 2011. Horseshoe Crab blood = $15,000. NG BBS. Available:
http://www.newgrounds.com/bbs/topic/1251364/1. (June 2011).
 Breese, G. 2009. Red Knot feeding on eggs of Horseshoe crabs. Wikipedia. Available:
http://en.wikipedia.org/wiki/File:Red_knot_horseshoe_crab_feeding.jpg. (June 2011).
 CCCMKC. 2005. Horseshoe crab menu. Available: http://cccmkc.edu.hk/~keikph/Fossil/Horseshoe%20crab%20menu.htm. (June 2011).
 Charles River Laboratories. 2011. Horseshoe crab (Limulus polyphemus) facts and
figures. Available:
http://info.criver.com/endotoxin_and_rapid_microbiological_products/horseshoecrab1.
html. (June 2011).
 Chernoff, D. 2011. Shoreline. Available: http://www.dcwild.com/index.htm. (May
2011).
 ERDG. 2009. The Horseshoe Crab. Ecological Research & Developmental Group.
Available: http://www.horseshoecrab.org/nh/life.html. (May 2011)
 Greer, S. 2007. Horseshoe crabs. Smithsonian National Museum of Natural History.
Available:
http://www.mnh.si.edu/exhibits/natures_best_2006/gallery/horseshoecrabs.html. (June
2011).
Photos Cited
 Rizzardi, K. 2009. With red knots on the candidate list, third circuit declares
emergency listing dispute moot. ESA BLAWG. Available:
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http://www.esablawg.com/esalaw/ESBlawg.nsf/d6plinks/KRII-7QA2EU. (June
2011).
Schaul, J. 2010. Horseshoe crabs need compassion and help to survive.
National Geographic News Watch. Available:
http://newswatch.nationalgeographic.com/2010/11/04/horshoe_crabs_need_co
mpassion/. (May 2011).
Skytitles. 2010. What types of hermit crabs should be placed in a saltwater
aquariums? Zimbio. Available:
http://www.zimbio.com/Pets+and+More+Pets/articles/r3J16YIXqzR/Types+He
rmit+Crabs+Placed+Saltwater+Aquariums. (June 2011)
Query, S. 2008. Crash: a tale of two species. Audobon. Available:
http://www.audubonmagazine.org/webexclusives/twospecieswebExclusives.html. (June 2011)
Volz, M. 2008. Limulus polyphemus: Atlantic Horseshoe Crab-Habitat.
UWLax Organismal Biology. Available:
http://bioweb.uwlax.edu/bio203/2011/volz_mack/contact.htm. (June 2011).
Questions????
(Greer 2007)