DOCSLIB.ORG

Native Predators Johan Hollander1 & Paul E

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Native Predators Johan Hollander1 & Paul E Evidence of weaker phenotypic plasticity by prey to novel cues from non-native predators Johan Hollander1 & Paul E. Bourdeau2 1Department of Biology, Aquatic Ecology, Lund University, Ecology Building, SE-223 62 Lund, Sweden 2Department of Biological Sciences, Humboldt State University, 1 Harpst St., Arcata, California 95521 Keywords Abstract Coevolution, inducible defensive traits, meta-analysis, naive interactions. A central question in evolutionary biology is how coevolutionary history between predator and prey influences their interactions. Contemporary global Correspondence change and range expansion of exotic organisms impose a great challenge for Johan Hollander, Department of Biology prey species, which are increasingly exposed to invading non-native predators, Aquatic Ecology, Lund University, Ecology with which they share no evolutionary history. Here, we complete a compre- Building, SE-223 62 Lund, Sweden. hensive survey of empirical studies of coevolved and naive predatorÀprey inter- Tel: +46 46 222 34 73; Fax: +46 46 222 45 36; actions to assess whether a shared evolutionary history with predators E-mail: [email protected] influences the magnitude of predator-induced defenses mounted by prey. Using marine bivalves and gastropods as model prey, we found that coevolved prey Funding Information and predator-naive prey showed large discrepancies in magnitude of predator- JH was funded by a Marie Curie European induced phenotypic plasticity. Although naive prey, predominantly among Reintegration Grant (PERG08-GA-2010- bivalve species, did exhibit some level of plasticity – prey exposed to native 276915) and the Swedish Research Council predators showed significantly larger amounts of phenotypic plasticity. We dis- (2015-05001). cuss these results and the implications they may have for native communities Received: 21 January 2016; Revised: 25 May and ecosystems. 2016; Accepted: 31 May 2016 Ecology and Evolution 2016; 6(15): 5358– 5365 doi: 10.1002/ece3.2271 Introduction reciprocally affect each other’s evolution (Ehrlich and Raven 1964; Dawkins and Krebs 1979; Brodie and Brodie Phenotypic plasticity is a developmental strategy where an 1999). Thus, the chemical signature of a coevolved preda- individual’s genotype has the ability to interact with its tor is likely to represent a reliable cue indicating risk to a environment and produce different phenotypes. The prey organism. However, since rapid globalization of the resulting phenotypic flexibility may increase an organ- world has increased species mobility and led to a growing ism’s fitness in a heterogeneous environment and it is a number of alien introductions of both animals and plants, common attribute across many taxa (Schlichting 1986; including many predatory species, prey species are Appleton and Palmer 1988; Whitman and Ananthakrish- increasingly being exposed to cues from predators with nan 2008; Hollander and Butlin 2010). which they share no evolutionary history (so-called naive Phenotypic plasticity is not considered likely to evolve interactions). Native prey species that are naive to cues if accessible cues are not reliable predictors of environ- and unable to alter their phenotype in response to novel mental change to the organism (Moran 1992; Tufto predators, or native prey that are less flexible in their abil- 2000). Indeed, in order for adaptive phenotypic plasticity ity to alter their phenotype in response to novel predators to evolve, predictable environmental cues, such as sea- will accordingly experience reduced fitness and a poten- sonal or systematic environmental change, or chemical tially larger extinction risk when exposed to non-native signals indicating the presence of a coevolved predator, invading, or range-expanding predators. are essential. Coevolution is the result of a shared evolu- In accordance with theory, which predicts that adaptive tionary history between two or more species that phenotypic plasticity will fail to evolve without reliable 5358 ª 2016 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. J. Hollander & P. E. Bourdeau Phenotypic Plasticity to Novel Cues cues (Moran 1992; Tufto 2000), there are a number of history) to predators. Studies that did not meet our crite- examples where naive prey fail to produce phenotypically ria were omitted from the data set. A number of studies plastic defensive traits (i.e., inducible defenses) when were rejected during this process because they were not exposed to novel predators (Edgell and Rochette 2007; related to the topic of bivalve or gastropod phenotypic Edgell and Neufeld 2008). However, in other cases, naive plasticity or they focused on the plasticity of predators prey have also been shown to respond plastically to novel rather than on the plasticity of bivalve or gastropod prey. predators (Freeman and Byers 2006; Rawson et al. 2007; The publication records in our data set covered from 1987 Bourdeau et al. 2013; Freeman et al. 2014; Hooks and to 2014 (Table 1) and identified 274 studies. In addition Padilla 2014). Thus, the general importance of evolution- to our literature exclusion process, we also searched the ary history/novelty in mediating plastic prey responses to references in the collected papers for supplementary litera- predators is still not well understood; accordingly, a more ture that was missed through keyword search. The data set comprehensive approach is called for to improve our has been submitted to DOI: doi:10.5061/dryad.b06f9. understanding concerning the evolution of adaptive phe- In order to summarize and quantify large sets of data, notypic plasticity in novel predatorÀprey interactions. meta-analysis has proved to be a powerful statistical tool. Marine molluscs such as bivalves and gastropods have a To create a consistent estimate of the quantitative mea- long history in the study of inducible defensive traits sure of phenotypic plasticity, we calculated a common (Appleton and Palmer 1988; Leonard et al. 1999; Trussell unit, the effect size, using the same methodology as in and Nicklin 2002; Edgell and Neufeld 2008; Bourdeau Hollander (2008); implementing Hedge’s d (Gurevitch 2009, 2010a; Freeman and Hamer 2009; Hollander and and Hedges 1993) as an effect size to quantify plasticity Butlin 2010). These taxonomic groups have served as a for each study. The data set was additionally divided into model owing to a number of beneficial characteristics, such four different variables in order to assess each variable as their accessibility on rocky and sandy shore habitats, separately. The four variables were as follows: life-history well-defined defensive traits that can easily be quantified, (comprising growth rate), behavior, shell morphology, and amenability to rearing in laboratory environments. For and soft tissue morphology. The soft tissue morphology that reason, there are numerous studies available in the describes the soft part of the animal, and in bivalves this published literature. Here, we provide a test where we syn- is often adductor mussel size or ‘meat’. We analyze these thesize previously published data, with the purpose of variables separately for both taxa together, and in examining whether prey species that are exposed to non- gastropods and bivalves exclusively. native predators (those without a shared evolutionary his- Hedge’s d uses arithmetic means of the phenotype from tory), whether prey show reduced phenotypic plasticity in the experimental group and correspondingly from the con- response to novel predators (those without a shared evolu- trol group’s mean phenotype. The equation to calculate tionary history) compared to prey that are exposed to Hedge’s d also requires the standard deviation and the native predators (with which they share an evolutionary sample size for each study from both the experimental and history). A benefit of this study system is the fact that sev- the control group. Studies are likely to vary in the degree eral of the species included in the present analysis are repre- of difference between treatments, which may influence the sented in each of the two contrasting groups: (1) naive phenotypic effect observed, but meta-analysis is robust to native prey exposed to non-native predators; and (2) expe- such variation(Rosenthal 1991) and it is unlikely to be rienced native prey exposed to native predators. confounded with the origin of the predator (native vs. non-native). Moreover, since we assumed a random com- Methods ponent of variation among effect sizes (Rosenthal et al. 2000), we used a mixed model. The analyses were con- We used ISI Web of Science (WoS) database and search ducted in the statistical software MetaWin 2.0 (Rosenthal engine to sample multiple independent studies published et al. 2000). Additionally, we used what is termed ‘Reversal in the peer-reviewed scientific literature. We used the fol- marker’ in the software, which enables the direction of the lowing search string to identify relevant papers by: effect between the control and the experimental treatments Topic = (snail* OR gastropod*) AND (plastic* OR phe- to always be positive (Gurevitch et al. 1992). In order to notyp* plastic* OR induce*) and (bivalve* or mussel* or test for the robustness of data due to publication bias (i.e., clam* or oyster*) AND (plastic* OR phenotyp* plastic* when negative results have a
Load more

Recommended publications
  • Marine Invertebrate Field Guide
    Marine Invertebrate Field Guide Contents ANEMONES ....................................................................................................................................................................................... 2 AGGREGATING ANEMONE (ANTHOPLEURA ELEGANTISSIMA) ............................................................................................................................... 2 BROODING ANEMONE (EPIACTIS PROLIFERA) ................................................................................................................................................... 2 CHRISTMAS ANEMONE (URTICINA CRASSICORNIS) ............................................................................................................................................ 3 PLUMOSE ANEMONE (METRIDIUM SENILE) ..................................................................................................................................................... 3 BARNACLES ....................................................................................................................................................................................... 4 ACORN BARNACLE (BALANUS GLANDULA) ....................................................................................................................................................... 4 HAYSTACK BARNACLE (SEMIBALANUS CARIOSUS) .............................................................................................................................................. 4 CHITONS ...........................................................................................................................................................................................
    [Show full text]
  • Download Download
    Appendix C: An Analysis of Three Shellfish Assemblages from Tsʼishaa, Site DfSi-16 (204T), Benson Island, Pacific Rim National Park Reserve of Canada by Ian D. Sumpter Cultural Resource Services, Western Canada Service Centre, Parks Canada Agency, Victoria, B.C. Introduction column sampling, plus a second shell data collect- ing method, hand-collection/screen sampling, were This report describes and analyzes marine shellfish used to recover seven shellfish data sets for investi- recovered from three archaeological excavation gating the siteʼs invertebrate materials. The analysis units at the Tseshaht village of Tsʼishaa (DfSi-16). reported here focuses on three column assemblages The mollusc materials were collected from two collected by the researcher during the 1999 (Unit different areas investigated in 1999 and 2001. The S14–16/W25–27) and 2001 (Units S56–57/W50– source areas are located within the village proper 52, S62–64/W62–64) excavations only. and on an elevated landform positioned behind the village. The two areas contain stratified cultural Procedures and Methods of Quantification and deposits dating to the late and middle Holocene Identification periods, respectively. With an emphasis on mollusc species identifica- The primary purpose of collecting and examining tion and quantification, this preliminary analysis the Tsʼishaa shellfish remains was to sample, iden- examines discarded shellfood remains that were tify, and quantify the marine invertebrate species collected and processed by the site occupants for each major stratigraphic layer. Sets of quantita- for approximately 5,000 years. The data, when tive information were compiled through out the reviewed together with the recovered vertebrate analysis in order to accomplish these objectives.
    [Show full text]
  • Seashore Beaty Box #007) Adaptations Lesson Plan and Specimen Information
    Table of Contents (Seashore Beaty Box #007) Adaptations lesson plan and specimen information ..................................................................... 27 Welcome to the Seashore Beaty Box (007)! .................................................................................. 28 Theme ................................................................................................................................................... 28 How can I integrate the Beaty Box into my curriculum? .......................................................... 28 Curriculum Links to the Adaptations Lesson Plan ......................................................................... 29 Science Curriculum (K-9) ................................................................................................................ 29 Science Curriculum (10-12 Drafts 2017) ...................................................................................... 30 Photos: Unpacking Your Beaty Box .................................................................................................... 31 Tray 1: ..................................................................................................................................................... 31 Tray 2: .................................................................................................................................................... 31 Tray 3: ..................................................................................................................................................
    [Show full text]
  • Kreis 1 Vertical Migration Patterns of Two Marine Snails: Nucella Lamellosa and Nucella Ostrina Maia Kreis [email protected] NERE
    Vertical migration patterns of two marine snails: Nucella lamellosa and Nucella ostrina Maia Kreis [email protected] NERE Apprenticeship Friday Harbor Laboratories Spring 2012 Keywords: Nucella lamellosa, Nucella ostrina, behavior, tide cycle, vertical migration, tagging methods, intertidal Kreis 1 Abstract Nucella ostrina and Nucella lamellosa are two species of predatory marine intertidal snail. They are common along the coast from California to Alaska, US and prey upon barnacles. We studied vertical migration and feeding patterns of each species and the best method for tagging them. We found that there was not much fluctuation in vertical movement, nor any significant peaks in feeding over our study period; however we did verify that N. lamellosa move up the shore a bit to feed. We also found that radio tagged N. lamellosa were more abundant lower on shore than their typical zone. These studies will help future studies on Nucella spp as well as further advance our efforts in predicting effects of climate change of behavior. Introduction Over the course of the next century, coastal regions are expected to experience a temperature increase of several degrees (IPCC 2007). Its effect on the natural world is a concern for many. Changes in temperature are likely to modify animal behavior. For example, Kearney (2009) found that lizards generally attempt to stay cool, e.g. by seeking shade when the sun comes out. If climate change decreases vegetation and therefore shade, lizards may have to spend more energy traveling to find food and shade (Kearney 2009). Similarly, climate change may alter organismal behavior along the coasts if warmer temperatures become stressful to marine ectotherms.
    [Show full text]
  • OREGON ESTUARINE INVERTEBRATES an Illustrated Guide to the Common and Important Invertebrate Animals
    OREGON ESTUARINE INVERTEBRATES An Illustrated Guide to the Common and Important Invertebrate Animals By Paul Rudy, Jr. Lynn Hay Rudy Oregon Institute of Marine Biology University of Oregon Charleston, Oregon 97420 Contract No. 79-111 Project Officer Jay F. Watson U.S. Fish and Wildlife Service 500 N.E. Multnomah Street Portland, Oregon 97232 Performed for National Coastal Ecosystems Team Office of Biological Services Fish and Wildlife Service U.S. Department of Interior Washington, D.C. 20240 Table of Contents Introduction CNIDARIA Hydrozoa Aequorea aequorea ................................................................ 6 Obelia longissima .................................................................. 8 Polyorchis penicillatus 10 Tubularia crocea ................................................................. 12 Anthozoa Anthopleura artemisia ................................. 14 Anthopleura elegantissima .................................................. 16 Haliplanella luciae .................................................................. 18 Nematostella vectensis ......................................................... 20 Metridium senile .................................................................... 22 NEMERTEA Amphiporus imparispinosus ................................................ 24 Carinoma mutabilis ................................................................ 26 Cerebratulus californiensis .................................................. 28 Lineus ruber .........................................................................
    [Show full text]
  • 2013-2015 Cherry Point Final Report
    Intertidal Biota Monitoring in the Cherry Point Aquatic Reserve 2013-2015 Monitoring Report Prepared for: Cherry Point Aquatic Reserve Citizen Stewardship Committee Prepared by: Michael Kyte Independent Marine Biologist and Wendy Steffensen and Eleanor Hines RE Sources for Sustainable Communities September 2016 Publication Information This Monitoring Report describes the research and monitoring study of intertidal biota conducted in the summers of 2013-2015 in the Cherry Point Aquatic Reserve. Copies of this Monitoring Report will be available at https://sites.google.com/a/re-sources.org/main- 2/programs/cleanwater/whatcom-and-skagit-county-aquatic-reserves. Author and Contact Information Wendy Steffensen North Sound Baykeeper, RE Sources for Sustainable Communities Eleanor Hines Lead Scientist, Clean Water Program RE Sources for Sustainable Communities 2309 Meridian Street Bellingham, WA 98225 [email protected] Michael Kyte Independent Marine Biologist [email protected] The report template was provided by Jerry Joyce for the Cherry Point and Fidalgo Bay Aquatic Reserves Citizen Stewardship Committees, and adapted here. Jerry Joyce Washington Environmental Council 1402 Third Avenue Seattle, WA 98101 206-440-8688 [email protected] i Acknowledgments Most of the sampling protocols and procedures are based on the work of the Island County/WSU Beach Watchers (currently known as the Sound Water Stewards). We thank them for the use of their materials and assistance. In particular, we thank Barbara Bennett, project coordinator for her assistance. We also thank our partners at WDNR and especially Betty Bookheim for her assistance in refining the procedures. We thank Dr. Megan Dethier of University of Washington for her assistance in helping us resolve some of the theoretical issues in the sampling protocol Surveys, data entry, quality control assistance and report writing were made possible by a vast array of interns and volunteers.
    [Show full text]
  • Comparative Anatomy of Four Primitive Muricacean Gastropods: Implications for Trophonine Phylogeny
    ^/ -S/ COMPARATIVE ANATOMY OF FOUR PRIMITIVE MURICACEAN GASTROPODS: IMPLICATIONS FOR TROPHONINE PHYLOGENY M. G. HARASEWYCH DEPARTMENT OF INVERTEBRATE ZOOLOGY NATIONAL MUSEUM OF NATURAL HISTORY SMITHSONIAN INSTITUTION WASHINGTON, D.C. 20560, U.S.A. ABSTRACT The main features of the shell, head-foot, palliai complex, alimentary and reproductive systems of Trophon geversianus (Pallas), Boreotrophon aculeatus (Watson), Paziella pazi (Crosse), and Nucella lamellosa (Gmelin) are described, and phonetic and cladistic analyses based on subsets of these data presented. Similarities in shell morphology revealed by phenetic studies are interpreted as being due to convergence, and are indicative of similar habitats rather than of close phylogenetic relationships. Convergences are also noted in radular and stomach characters. Cladistic analyses of anatomical data support the following conclusions: 1 ) Thaididae are a primitive and ancient family of muricaceans forming a clade equal in taxonomic rank with Muncidae; 2) Within Muricidae, P. pazi more closely resembles the ancestral muricid phenotype than any trophonine; 3) Trophoninae comprise a comparatively recent monophyletic group with differences due to a subsequent austral adaptive radiation. The Muricidae are considered to be the most primitive and D'Attilio, 1976:13) a personal communication from E. H. family within Neogastropoda according to most (Thiele, Vokes "it appears likely that the most northern trophons are 1929; Wenz, 1941; Taylor and Sohl, 1962; Boss, 1982) but derived from the Paziella-Poiheha line, and that the several not all (Golikov and Starobogatov, 1975) recent classifica- austral forms that are unquestionably "trophonine" are prob- tions. Of the five subfamilies of Muricidae, the Trophoninae, ably derived from the Thaididae". proposed by Cossmann (1903) on the basis of shell and Thus, according to most published work, the Tropho- opercular characters to include a number of boreal and ninae are in a position to shed light on the systematics and austral species, are the most poorly understood.
    [Show full text]
  • Nucella Lamellosa Class: Gastropoda, Caenogastropoda
    Phylum: Mollusca Nucella lamellosa Class: Gastropoda, Caenogastropoda Order: Neogastropoda A gammarid amphipod Family: Muricoidea, Muricidae, Ocenebrinae Taxonomy: Nucella was previously called 1974); encrusted, smooth. Thais. Thais is now reserved for subtropical Suture: Impressed, distinct, but not a and tropical species. For a more detailed deep groove. review of gastropod taxonomy, see Keen Anterior (Siphonal) Canal: Short, but and Coan (1974) and McLean (2007). longer than other Nucella species; narrow, slot-like, not spout-like (i.e. with edges touch- Description ing, making a closed tube: see Possible Misi- Size: To 50 mm in California (Abbott and dentifications). Not separated from large Haderlie 1980), 100 mm Puget Sound and whorl by revolving groove (fig. 1). north (Kozloff 1974); largest specimen illus- Umbilicus: Small, often closed (fig. 1). trated, 54 mm (fig. 1). Largest of the Nucella Aperture: Almost 1/2 length shell; genus. ovate to quadrate in outline, with a siphonal Color: White to brown, some are pink, lav- notch, but no anal notch (fig. 1). Widest part ender or orange tan; not highly polished. In- of aperture (generally near its middle) at least side whitish, sometimes with color showing half as wide as shell (Kozloff 1974). through. Outer Lip: Thickened, smooth, without General Morphology: denticles on posterior portion of aperture Shell: (near anal notch) no single strong tooth on Shape: Shell heavy, solid, strong; edge near anterior canal (see Possible Misi- spirally coiled, fusiform (spindle-shaped). 5- dentifications). Outer lips rounding smoothly 7 whorls; nuclear whorl small, inconspicu- to anterior end of shell. At least one row of ous. Spire usually high; siphonal canal rela- denticles within lip (fig.
    [Show full text]
  • Nucella Lamellosa Class: Gastropoda, Prosobranchia Order: Neogastropoda the Wrinkled Or Frilled Dogwinkle Family: Muricidae
    Phylum: Mollusca Nucella lamellosa Class: Gastropoda, Prosobranchia Order: Neogastropoda The wrinkled or frilled dogwinkle Family: Muricidae Taxonomy: Nucella was previously called groove. Thais. Thais is now reserved for subtropical Anterior (Siphonal) Canal: Short, but longer and tropical species. For a more detailed than other Nucella species; narrow, slot-like, review of gastropod taxonomy, see Keen and not spout-like (i.e. with edges touching, Coan (1974) and McLean (2007). making a closed tube: see Possible Misidentifications). Not separated from large Description whorl by revolving groove (fig. 1). Size: To 50 mm in California (Abbott and Aperture: Almost 1/2 length shell; ovate to Haderlie 1980), 100 mm Puget Sound and quadrate in outline, with a siphonal notch, but north (Kozloff 1974); largest specimen no anal notch (fig. 1). Widest part of aperture illustrated, 54 mm (fig. 1). Largest of the (generally near its middle) at least half as Nucella genus. wide as shell (Kozloff 1974). Color: White to brown, some are pink, Umbilicus: Small, often closed (fig. 1). lavender or orange tan; not highly polished. Operculum: Usually large enough to close Inside whitish, sometimes with color showing aperture; conspicuous, with strong spiral through. lines; with nucleus on one side (fig. la). Shell Shape: Shell heavy, solid, strong; Eggs: Vase-shaped, yellow, about 10 mm spirally coiled, fusiform (spindle-shaped). 5-7 long; in clusters on underside of rocks (Abbott whorls; nuclear whorl small, inconspicuous. and Haderlie 1980); called "sea oats"; (fig. Spire usually high; siphonal canal relatively 1B). long for genus; aperture ovate, almost 1/2 shell length. Possible Misidentifications Sculpture: Extremely variable.
    [Show full text]
  • Common Seashore Animals of Southeastern Alaska a Field Guide by Aaron Baldwin
    Common seashore animals of Southeastern Alaska A field guide by Aaron Baldwin All pictures taken by Aaron Baldwin Last update 9/15/2014 unless otherwise noted. [email protected] Seashore animals of Southeastern Alaska By Aaron Baldwin Introduction Southeast Alaska (the “Alaskan Panhandle”) is an ecologically diverse region that extends from Yakutat to Dixon Entrance south of Prince of Wales Island. A complex of several hundred islands, fjords, channels, and bays, SE Alaska has over 3,000 miles of coastline. Most people who live or visit Southeast Alaska have some idea of the incredible diversity of nature found here. From mountain tops to the cold, dark depths of our many fjords, life is everywhere. The marine life of SE Alaska is exceptionally diverse for several reasons. One is simply the amount of coast, over twice the amount of the coastline of Washington, Oregon, and California combined! Within this enormous coastline there is an incredible variety of habitats, each with their own ecological community. Another reason for SE Alaska’s marine diversity is that we are in an overlap zone between two major faunal provinces. These provinces are defined as large areas that contain a similar assemblage of animals. From northern California to SE Alaska is a faunal province called the Oregonian Province. From the Aleutian Island chain to SE Alaska is the Aleutian Province. What this means is that while our sea life is generally similar to that seen in British Columbia and Washington state, we also have a great number of northern species present. History of this guide http://www.film.alaska.gov/ This guide began in 2009 as a simple guide to common seashore over 600 species! In addition to expanding the range covered, I animals of Juneau, Alaska.
    [Show full text]
  • Pheno~Pic Plasticity in Marine Intertidal Gastropods DOCTOR OF
    Pheno~pic plasticity in marine intertidal gastropods By Ahmed Mohammed AI-Mazrouai A thesis submitted to the University of Plymouth in partial fulfilment for the degree of DOCTOR OF PHILOSOPHY School of Biological Sciences Faculty of Science November 2008 Ill Phenotypic plasticity in marine intertidal gastropods by Ahmed Mohammed AI- Mazrouai Abstract Phenotypic plasticity, the differential phenotypic expression of the same genotype in response to different environmental conditions, is a paradigm central of the study of evolution and ecology and is at the core of the "nature versus nurture" debate. Here, the marine gastropod Littorina littorea was used as a model to further our understanding of the potential role of phenotypic plasticity in intertidal systems. In the first study L. littorea was included in an investigation of induced defences across six species of intertidal marine gastropods in the families Littorinidae and Trochidae. Species differed in the magnitude and type of plastic response, which appeared to relate to their susceplihility Lo crab predation. Chapters three and four revealed that L. littorea was able to alter its degree of morphological plasticity depending on temporal variation in predation threat. Snails exposed to predation threat halfway through trials appeared to "catch up" snails continuously exposed to predator cues in, terms oftheir shell size, whereas snails experiencing a removal of predation cues showed a significant reduction in growth rate following this switch in predation. environment. A further investigation suggested that Littorina littorea demonstrated no significant difference in the morphological traits under variable predator threat versus a constant predator' threat environment. Finally, the interaction between biotic (predator) and abiotic (temperature) environmental effects revealed that snails maintained at 16 and 20° C demonstrated significant induced defences by growing larger and thicker shells, but there was no significant difference in induced defences between these two temperatures.
    [Show full text]
  • Predation in Molluscs: a Multi-Taxon Approach Using Neontological and Paleontological Data
    PREDATION IN MOLLUSCS: A MULTI-TAXON APPROACH USING NEONTOLOGICAL AND PALEONTOLOGICAL DATA by Devapriya Chattopadhyay A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy (Geology) in The University of Michigan 2009 Doctoral Committee: Professor Tomasz K. Baumiller, Chair Professor Daniel C. Fisher Professor Kyger C. Lohmann Assistant Professor Thomas F. Duda Jr. Assistant Professor Jeffrey A. Wilson Research Scientist Janice L. Pappas ACKNOWLEDGEMENTS I want to extend my sincere gratitude to my academic adviser Prof. Tomasz K. Baumiller who introduced me to the modern trends in Paleontology. I wish to thank Prof. Michal Kowalewski of Virginia Polytechnic Institute and State University and Prof. Lindsey Leighton of University of Alberta who helped me to carry out the neontological experiments. Special thanks to Dr. Daniel J. Miller and G. Alex Janevski for numerous valuable discussions that significantly improved my dissertation. UROP student Sarah Groat helped me in collecting data from the museum specimens. I would like to thank my collaborator Ms. Michelle Casey (Yale University) for her part in our joint study that I included as an appendix in this dissertation. I am indebted to Dr. John Huntley for sharing his data on Phanerozoic predation intensity (Chapter VI). I wish to thank Ms. Anne Hudon for her unrelenting help with all official procedures that could be quite challenging for an international student. My sincere thanks to all the members of Museum of Paleontology who provided useful criticism that improved my work. My husband, Anirban Dutta stood by me in good time and in not so good times.
    [Show full text]