Limulus polyphemus

(Schaul 2010)

OutlineHorseshoe Crab Overview

BackgroundPhysical featuresReproduction

Nest SitesLife cycle

Endangered?Why care?

Important ecologically for migratory birdsProduction of LALBait for commercial harvesting of whelk and

eelFuture Research?

BackgroundPhylum Arthropoda

Dates from Cambrian period

Habitatshallow water along North American Atlantic

coast

Swims with abdominal platesWalks with walking legs

Feed at night – worms & small mollusks

(Chernoff 2011)

Physical Features

Ventral View

(CCCMKC 2005)

(Skytitles 2010)

Dorsal View

ReproductionNeeded:

High tideSpring/summer

seasonSexually mature

female and male(s)

Process:Female buries eggs

into sand External

fertilization

(Query 2008)

Reproduction: Who’s the Daddy?

(Brockmann et al. 1994)

Low Tide

Location, location, location!Just above mean high tide

lineSandy beachesSloped beaches

Nest Sites(ERDG 2009)

(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 crabs20-25% of stranded from sloped beach

Blinded/Partially blinded HsCSimilar data

(Penn & Brockmann 1994)(Penn & Brockmann 1994)

(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 threatsMaturation durationDangers during matingEgg/larval mortality

HarvestingBiomedical research & companiesScientific researchBait for fisheries

Why Care? Important ecologically for migratory

birds

Production of LAL

Bait for commercial harvesting of whelk and eel$ Economy $

(Karpanty et al. 2006)

(Rizzardi 2009)

(Breese 2009)

Limulus Amoebocyte Lysate (LAL)

(Blackfang 2011)

(Charles River Laboratories2011)

Further ResearchPopulation structure

Sex structure

Limited studiesConfined to

Delaware BayMost research on

spawning populations

(Volz 2008)

Literature Cited 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/~kei-kph/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: 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_compassion/. (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+Hermit+Crabs+Placed+Saltwater+Aquariums. (June 2011)

Query, S. 2008. Crash: a tale of two species. Audobon. Available: http://www.audubonmagazine.org/webexclusives/twospecies-webExclusives.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).

(Greer 2007)