causes and consequences of arm damage in the sea star Leptas

causes and consequences of arm damage in the sea star Leptasterias hexactis Brian L. Bingham, Jennifer Burr, and Herb wounded Head Abstract sw rias bewaens, a sea star common in rocky ntertidal areas of Paget Sound. Washing on, onen bas missing arms. We measured the frequency damage in populations and examined the causes and costs of the damage. Between 30 and 46%E of heractis found at the study sites were missing arms or Some of the damage, particularly when only parts of arms were missing. may result from Physical disturbence ng). Mon amm damage, however, appears to result from predation by the crab Cancer oregonens arms has adapti ve significance if it saves a sea star from death. also carries costs. The cost was a decrease in reproduction. Lepasserias hetactis missing arms show od 44-6 drop in egg produc- 7 months after arm loss. The effect was still evident during the next reproductive season (19 months afier arn loss). We estimale that natural levels of anm damage could decrease the reproductive output of a populau Résumé Lepnasterias hexacris, une éloile de mer commune dans les zones intertidales rocheuses du fond de Puget on, a souvent les bras endommagés Nous avons mesure la fréq bras chez 5 et en avons examine les causes nous avons également évalué les coats reliés ces blessures De 30 46 des L heranns de la zone étudiée com ptaient des bras ou des parties de bras endommages. Certains des iculierement lorsqu\'il ne manquait que des parties de bras. peuvent avoir résulte d\'une physique (eg écrasement). La plupart des blessures aux bras, cependa nts semblent résulter de la prédation par le crabe Cancer oregonens La tolerance autotomisation a une grande importance evolutive elle peut sauver la vie d\'une étoile de mer. Cependant, cela ne va pas sans cout. Le cout le plus élevé est la diminution de la Les étoiles de mer qui ont perdu des bras ont produit de 44 a 69% moins d\'oeufs 7 mois apres la perte de bras. L\'effet était encore pereeptible durant la saison reproduction suivante (19 mois apres la perte de bras). Nous estimons que l\'importance des dommages naturels aux bras peut diminuer la performance reproductrice de la po pulation de L. hetactis de 7 10 ITraduit par la Rédactionl Introduction (Hancock 1955. 1974: Mauzey et al. 1968: Viviani 1978 Birkeland et al. 1982; reviewed by Lawrence 1992) Sea stars are well known for their capacity to lose, then Autotomy of an arm has obvious advantages if it allows a regenerate, body parts, particularly arms (reviewed by Law- sea star to escape death: a portion of the body is lost, but th rence and Vasquez 1996). Purely physical processes can sea star lives to regenerate the limb. Lawrence 992) sugg cause arm damage. For example, sea stars in habitats with gested that dropping damaged limbs is also adaptive if heavy wave action and shifting rocks are often lacking arms decreases the chances of infection or (i) stops leakage o or parts of arms (Niesen 1973: Lawrence and Dehn 1979. predator-attracting metabolites Town 1979). Predation can also cause arm loss. For exam- Despite long-standing knowledge that sca stars can los Glynn (1982) reported that shrimp damage the crown- and regenerate arms, and indications that this occurs of thoms sea star, Acantiaster planci, by picking at the sur- many starfish species (Lawrence 1992), we know face of its arms. The sea star responds by dropping the damaged its causes or consequences in natural populations. Lawrenc arm and moving to safety, Sea suars may escape aggressive and Vasquez (1996) suggest that autotomy may have signifi predators by autotomizing the arms in the predator\'s grip cant costs, including lower starvation resistance, reduce Received July 7, 1999, Accepted November 12, 1999 lsu.. Bingham.\' Huxley College of Environmental Studies. Western Washington University. Bellingham. WA 98225. USA J. Burr, Biology Department, Pacific Lutheran Unive Tacoma, WA 98447. U SA H. Wounded Head. Black Hills State University, Spearfish, SD S7783. U SA. Author to whom all correspondence should be addressed (e-mail: bingham@cc.wwu.edu). CA. Viviani. 1978. Predaction interespecifica, canibalismo y autolomi como mecanismo de escape en el litoral del diserto del a e Gnade de Chile. Unpublished report from the Laboratorio de Ecol Marina. Universidad del Norte, lqutique, Chile Can, Zool 78 596-605 2000 NRC Cana

Solution

The correct APA format to cite this paper would be:

Author, A.A.. (Publication year).Article title. periodical title, Volume(Issue), pp.-pp.

so here it should go like :

the authors name: Bingham, B.L., Burr,J., & Head, H.W

the publication year is 2000 as written on the bottom left,

article title is : Causes and consequences of arm damage in the sea star Leptasterias hexactis.

the periodical in which it is published is : Can .J. Zool or Canadian Journal of Zoology ,

volume issue is 78

and pp is 596 - 605

therefore the entire citation would be :

Bingham, B. L., Burr, J., & Head, H. W. (2000). Causes and consequences of arm damage in the sea star Leptasterias hexactis. Canadian Journal of Zoology, 78(4), 596-605.