Journal of the Marine Biological Association of the United Kingdom, 2012, 92(7), 1595–1601. # Marine Biological Association of the United Kingdom, 2012 doi:10.1017/S0025315412000173 Impact of wave exposure on seasonal morphological and reproductive responses of the intertidal limpet crassa (: Archaegastropoda) jose’ pulgar1, marcos alvarez5, alejandro delgadillo1,4, ines herrera1, samanta benitez1,2, juan pablo morales5, pilar molina3, marcela aldana1,3,6 and victor manuel pulgar7 1Universidad Andres Bello, Departamento de Ecologı´a & Biodiversidad, Repu´blica 470, Santiago Chile, 2Universidad Andres Bello Escuela de Biologı´a Marina, Repu´blica 440, Santiago, Chile, 3Pontificia Universidad Cato´lica de Chile, Alameda 370, Santiago, Chile, 4Escuela de Ingenierı´a en Acuicultura, Universidad Andres Bello, Repu´blica 440, Santiago, Chile, 5Universidad Andres Bello, Facultad de Ciencias Biolo´gicas, Repu´blica 217, Santiago, Chile, 6Escuela de Pedagogı´a en Biologı´a y Ciencias, Facultad de Ciencias de la Educacio´n, Universidad Central de Chile, Santa Isabel 1278, Santiago, 7Center for Research in Obstetrics & Gynecology, Wake Forest School of Medicine and Biomedical Research Infrastructure Center, Winston-Salem State University, Winston-Salem NC, USA

Intertidal organisms have long been considered an ideal system to quantify how physical variations determine differential energy allocations in specimens inhabiting environmental gradients such as exposure to wave action. In habitats with differ- ential intertidal wave exposure (sheltered, Sh; and exposed, E) seasonal gonadal and foot weight variations and their associ- ations with exposure and food availability (algae abundance) were determined in the keyhole limpet Fissurella crassa. Gonadal weight is used as a measure of reproduction allocation whereas foot weight is an indirect indicator of energy allo- cation to survival. RNA:DNA ratio in limpets obtained from Sh and E habitats during the two different seasons was used as an indicator of biosynthetic capability. Our results indicate that algae abundance in E sites was higher in summer and lower in winter compared to Sh sites. In E sites the muscular foot weight of limpet was higher in summer in contrast to Sh sites where F. crassa muscular foot weight of limpet was higher in winter. Gonadal weight in Sh sites was higher in summer and remained constant in winter; whereas in E sites gonadal weight was lower in summer and higher in winter. RNA:DNA ratios indicate that regardless of intertidal wave exposure, F. crassa showed higher biosynthetic capability in summer. Energetic allocation in that inhabit sheltered intertidal habitats would support constant allocation towards reproduction. In contrast, animals that inhabit exposed habitats may favour seasonally reproduction allocation at expense of survival.

Keywords: shell morphology, RNA:DNA ratio, energetic trade-off

Submitted 17 January 2012; accepted 25 January 2012; first published online 28 March 2012

INTRODUCTION Wagner et al., 1998; Dahlhoff, 2004; Pulgar et al., 2011). Physiological constraints are important determinants of the Diversity and variability are key characteristics of life distribution limits of and populations (Gaston & (Spicer & Gaston, 1999). Environmental factors influence an Spicer, 1998; Chown & Gaston, 2000); however, processes animal’s condition at several levels of biological organization, associated with environmental tolerance explaining for including organismal (e.g. feeding rate and metabolic rate: example differential habitat use at the local scale, or species Sanford, 2002) subcellular levels (e.g. protein synthesis and distribution patterns at the geographical scale, remain gene expression: Somero, 2002). To understand the effects poorly understood. of climate change on biological phenomena throughout the Rocky intertidal habitats experience a wide range of phys- biosphere (Hofmann, 2005) is important to evaluate the ical conditions, with daily and seasonal variability including: organism’s responses to environmental variations. As a degree of immersion; isolation; nutrient availability; and result, there has been increasing interest in determining the exposure to different levels of wave action (Newell, 1970; variability in physiological condition and life-history traits Truchot & Duhanel-Jouve, 1980). Organisms that inhabit of organisms in their natural habitats (Colman, 1933; intertidal rocky shores are strongly influenced by a vertical tidal emersion (Denny, 1988; Helmuth & Hofmann, 2001;

Corresponding author: Somero, 2002) and a horizontal wave exposure gradient J. Pulgar (Jones & Demetropoulos, 1968; Dahlhoff et al., 2002). In inter- Email: [email protected] tidal organisms, biochemical and physiological processes and

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