CHAPTER 2: REVIEW OF RELATED LITERATURE

Transcription

1 4. There will not be any significant spatio-temporal variations in the population of the selected hermit crab species in the selected shore areas. CHAPTER 2: REVIEW OF RELATED LITERATURE This chapter deals with the review of the related literature. The purpose of the review of related literature is to understand what type of study has been done and what exactly has been explored before the present research work started. The study of related literature and past research work is very essential and important as it provides proper guidelines for each and every step in between starting point of research to the finishing line. The study of related literature is very important for any research. The phase review of literature consists of two words, Review and Literature. The term review means to organize the knowledge of the specific area of research to evolve construction of the knowledge to show that the projected study would be an addition to this field. In research methodology, the term literature refers to the knowledge of a particular area of investigation of any discipline, which includes theoretical, practical and its research studies. According to Wikipedia an Encyclopedia (2015) A literature review is a text of a scholarly paper, which includes the current knowledge including substantive findings, as well as theoretical and methodological contributions to a particular topic. Literature reviews use secondary sources, and do not report new experimental work. According to (Moully, 1984) the review of the related literature is essential to the development of the problem and to the derivation of effective approach to its solution. The study of related research work is very important to make the research more effective. The outputs, gain knowledge and techniques used in previous related literature prove useful in research work. Therefore, for each study it is very important to observe the previous studies and related literature. This section has the details of related literature for the present study included theoretical discussion (Uchat et al., 1998) narrates that, Ideal situation is that, the researcher has to prepare the review of the related literature before starting his work study, then only the basement of the workstudy can be prepared. Review of the related literature allows the researcher to 62

2 acquaint himself with the content (in this research hermit crab) and past researches in the field in which he is going to conduct his research. There are many scientists who tried to show the importance of review of the related literature. To collect the related research reports, the researcher referred past and current issues of the journals like Journal of Experimental Marine Biology and Ecology, Crustaceana, Hydrobiologia, Zootaxa, Journal of Crustacean Biology, Journal of Sea Research, Zookeys, Tropical Zoology, Marine and Freshwater Behaviour and Physiology, Journal of Natural History, Marine Biology Research, Marine Biodiversity, BMC Evolutionary Biology, Zoomorphology, Aquatic Invasions, Arthropods, Taprobanica, Oecologia, Estuarine, Coastal and Shelf Science, American Journal of Life Sciences, Molecular Phylogenetics and Evolution, Animal Behavior, Journal of Biosciences, Coral Reefs, The Raffles Bulletin of Zoology, Nauplius, Iranian Journal of Animal Biosystematics, Biological Bulletin, Cell Tissue Research, Aquatic Biology, Journal of Comparative Physiology and Biology, The American Naturalist, Ecology, Zoologische verhandelingen, Marine Biology etc.. Many research papers were chosen and downloaded from the Internet. The other resources were also refereed like Springer, Science direct, Google scholar, Ask, Wikipedia, Encyclopedia of Life, INFLIB Net, Shodhganga, Shodhgangotri, The Global Biodiversity Information Facility, Ocean Biogeographic Information System, FishBase, The Census of Marine Life ( ), The WoRMS-World Register of Marine Species, BHL-Biodiversity Heritage Library, The Global Network for Taxonomy (BioNET), The Global Ocean Observing System (GOOS), Indian Biodiversity Portal (IBP), Large marine Ecosystems (LMEs), National Centre for Biotechnology Information (NCBI), Royal Zoological Society (RZS), Zoological survey of India (ZSI), Google, Mamma, Yahoo, and other departmental websites of different universities. Departmental and University library had also provided other related journals and thesis for reference. After comprehensive efforts, related researches were collected for the review. After collection of the related researches, the abstract of each research was noted and then each abstract was reviewed. Various researchers had studied different aspects of hermit crabs. Studies of hermit crab shell were reported by many researchers from different geographical areas. A summary of title, author and year is presented in this section, Hermit crabs (Pagurus spp.) at their northernmost range: distribution, abundance and shell use in the European 63

3 Arctic (Balazy et al., 2015). Influence of the commensal gastropod Crepidula plana on shell choice by the marine hermit crab Pagurus longicarpus, with an assessment of the degree of stress caused by different eviction techniques (Pechenik et al., 2015). What motivates hermit crabs to abandon trapped shells? Assessing the influence of shell value, olfactory attractants, and previous experience (Gorman et al., 2014). Intraspecific competition of Pagurus samuelis on shell selection and recognition (Mortazavi, 2014). Ontogenetic changes in shell preferences and resource partitioning by the hermit crabs Pagurus hirsutiusculus and P. granosimanus (Straughan and Gosselin, 2014). Shell use and partitioning of two sympatric species of hermit crabs on a tropical mudflat (Teoh and Chong, 2014). Subjective resource value and shell abandoning behavior in hermit crabs (Turra and Gorman, 2014). Shell occupation by the South Atlantic endemic hermit crab Loxopagurus loxochelis (Moreira, 1901) (Anomura: Diogenidae) (Frameschi et al., 2013). Hermit crab population structure and association with gastropod shells in the northern bering sea (Peura, 2013). Shell preference in a hermit crab: comparison between a matrix of paired comparisons and a multiple-alternative experiment (Arce and Alcaraz, 2012). Shell use by the hermit crab Calcinus californiensis at different levels of the intertidal zone (Arce and Alcaraz, 2011). Shell utilization by the hermit crab Clibanarius antillensis Stimpson 1862 (Crustacea Anomura) in intertidal rocky pools at Montepio, Veracruz, Mexico (Argüelles-Tico et al., 2010). The role of previous shell occupancy in the wild on laboratory shell choice by the hermit crab Calcinus californiensis (Alcaraz and Kruesi, 2009). Shell Utilization by the Hermit Crab, Diogenes planimanus (Anomura: Diogenidae) From Karachi Coast, Pakistan (Fatima, 2007). Polychaete communities associated with gastropod shells inhabited by the hermit crabs Clibanarius erythropus and Calcinus tubularis from Ibiza, Mediterranean Sea (Bick, 2006). Pattern of shell occupation by the hermit crab Pagurus exilis (Anomura, Paguridae) on the northern coast of São Paulo State, Brazil (Terossi et al., 2006). The use of artificial shells for exploring shell preference in the marine hermit crab Pagurus longicarpus (Say) (Gravel et al., 2004). Shell choice in Pagurus longicarpus hermit crabs: Does predation threat influence shell selection behavior? (Rotjan et al., 2004). Hermit crab population ecology on a shallow coral reef (Bailey s Cay, Roatan, Honduras): octopus s predation and hermit crab shell use (Gilchrist, 2003). Shell condition and adequacy of three sympatric intertidal hermit crab populations (Turra, 2003). Effect of Size on Intraspecific Shell Competition in the Endemic Bermudian Hermit Crab, Calcinus verrilli (Rathbun, 1901) (Decapoda, 64

4 Anomura) (Rodrigues et al., 2002). Shell utilization patterns of a tropical intertidal hermit crab assemblage (Turra and Leite, 2002). Population structure and shell use in the hermit crab, Clibanarius erythropus: a comparison between Mediterranean and Atlantic shores (Benvenuto and Gherardi, 2001). Effects of shell fit on the biology of the hermit crab Pagurus longicarpus (Say) (Angel, 2000). Shell Utilization Pattern of the Hermit Crab Calcinus tibicen (Diogenidae) from Southern Brazil (Mantelatto and Garcia, 2000). Shell utilization by the hermit crabs Diogenes pugilator (roux, 1829). Paguristes eremita (linnaeus, 1767) and Pagurus Forbesii bell, 1845 (crustacea: decapoda: anomura), in a Shallow-water community from southern Spain (Manjón- Cabeza and García, 1999). Hermit crabs (Crustacea: Decapoda: Anomura), gastropod shells and environmental structure: their relationship in southeastern Brazil (Leite, et al., 1998). Use of chemical cues for shell preference by the hermit crab, Pagurus samuelis (Benoit et al., 1997). Comparative study of hermit crab responses to shellrelated chemical cues (Hazlett, 1996). Shell dynamics and microhabitat selection by striped legged hermit crabs, Clibanarius vittatus (Bose) (Rittschof et al., 1995). Influence of size, species and damage on shell selection by the hermit crab Pagurus longicarpus (Wilber, 1990). Associations between Gastropod Shell Characteristics and Egg Production in the Hermit Crab Pagurus longicarpus (Wilber, 1989). A Graphical Model for Shell-Species Selection by Hermit Crabs (Lively, 1988). Shell Wars: Assessment Strategies and the Timing of Decisions in Hermit Crab Shell Fights Stable (Dowds and Elwood, 1983). The Influence of Shell-Type on Hermit Crab Growth Rate and Clutch Size (Decapoda, Anomura) (Bertness, 1981) and Availability and use of shells by intertidal hermit crabs (Spight, 1977). The population aspacts of hermit crabs were studied by many researchers a summary of title, author and year is presented. Reproduction strategies and population dynamics of two Diogenes hermit crabs (Superfamily: Paguroidea) in a tropical mangrove estuary (Teoh and Chong, 2014). Hermit crab population structure and association with gastropod shells in the northern bering sea (Peura, 2013). Population structure and association with gastropod shells in the northern Bering Sea (Peura et al., 2013). Temporal changes in the reproductive population structures and males secondary sexual character of the hermit crab Diogenes nitidimanus (Koga et al., 2010). Spatial and Temporal Variations in Population Dynamics of Few Key Rocky Intertidal Macrofauna at Anthropogenically Influenced Intertidal shoreline (Vaghela, 2010). 65

5 Population structure and breeding season of the hermit crab Diogenes brevirostris Stimpson, 1858 (Decapoda, Anomura, Diogenidae) from southern Mozambique (Litulo and Tudge, 2005). Hermit crab population ecology on a shallow coral reef (Bailey s Cay, Roatan, Honduras): octopus s predation and hermit crab shell use (Gilchrist, 2003). Population dynamics and epibiont associations of hermit crabs (Crustacea: Decapoda: Paguroidea) on Dog Island, Florida (Sandford, 2003). Population biology and growth of the hermit crab Dardanus insignis at Armacao do Itapocoroy, southern Brazil (Branco et al., 2002). Shell utilization patterns of a tropical intertidal hermit crab assemblage (Turra and Leite, 2002). Population biology of the hermit crab Petrochirus diogenes (Linnaeus) (Crustacea, Decapoda) in Southern Brazil (Turra et al., 2002). Morphological and genetic evidence for vicariance and refugium in Atlantic and Gulf of Mexico populations of the hermit crab Pagurus longicarpus (Young, et al., 2002). Population structure and shell use in the hermit crab, Clibanarius erythropus: a comparison between Mediterranean and Atlantic shores (Benvenuto and Gherardi, 2001). Clustering behaviour in a mediterranean population of the hermit crab, Clibanarius erythropus (Gherardi and Benvenuto, 2001). Fecundity of Three Sympatric Populations of Hermit Crabs (Decapoda, Anomura, Diogenidae) (Turra and Leite, 2001). Population biology of the hermit crab Paguristes tortugae Schmitt, 1933 (Anomura, Diogenidae) from Anchieta Island, Ubatuba, Brazil (Mantelatto and Sousa, 2000). Population biology and growth of three sympatric species of intertidal hermit crabs in south-eastern Brazil (Turra and Leite, 2000). The Question of Coexistence in Hermit Crabs: Population Ecology of a Tropical Intertidal Assemblage (Gherardi and Nardone, 1997) and Population ecology of the sand-dwelling hermit crab Diogenes nitidimanus. IV.Larval settlement (Asakura, 1991). The following studies were conducted on genus Diogenes. Reproduction strategies and population dynamics of two Diogenes hermit crabs (Superfamily: Paguroidea) in a tropical mangrove estuary (Teoh and Chong, 2014). On the occurrence of Diogenes pugilator in the German Bight (Crustacea: Decapoda Diogenidae). A new species of the hermit crab genus Diogenes (Crustacea: Decapoda: Anomura: Diogenidae) from southern India (Turkay, 2014). A new species of the hermit crab genus Diogenes (Crustacea: Decapoda: Anomura: Diogenidae) from southern India (Komai et al., 2013). New records of hermit crabs, Calcinus morgani (Rahayu and Forest, 1999) and Diogenes klaasi (Rahayu and Forest, 1995) (Crustacea: Anomura: 66

6 Diogenidae) from India (Reshmi and Bijukumar, 2011). Temporal changes in the reproductive population structures and males secondary sexual character of the hermit crab Diogenes nitidimanus (Koga et al., 2010). Discovery of Larvae of the Hermit Crab Diogenes nitidimanus Terao, 1913 (Decapoda: Diogenidae) in Ship Ballast Waters: Evidence in Support of Its Introduction into Peter the Great Bay (Zvyagintsev and Kornienko, 2008). Shell Utilization by the Hermit Crab, Diogenes planimanus (Anomura: Diogenidae) From Karachi Coast, Pakistan (Fatima, 2007). Diogenes patae n. sp., a new species of hermit crab (Crustacea, Decapoda, Anomura, Diogenidae) from American Samoa (Asakura and Godwin, 2006). Shallow water hermit crabs of the Families Pylochelidae, Diogenidae and Paguridae (Crustacea: Decapoda: Anomura) from the Sea of Japan, with a description of a new species of Diogenes (Asakura, 2006). Population structure and breeding season of the hermit crab Diogenes brevirostris Stimpson, 1858 (Decapoda, Anomura, Diogenidae) from southern Mozambique (Litulo and Tudge, 2005). Influence of antiangiogenic fraction from Diogenes avarus (Heller, 1865) on fertility and implantation in mice (Pathare et al., 2004). Review of the Pakistani species of Diogenes Dana 1851(Decapoda Anomura Paguroidea Diogenidae) (Siddiqui et al., 2004). A new species of Pseudopaguristes McLaughlin, 2002 (Crustacea: Decapoda: Diogenidae) from Japan (Asakura and Mclaughlin, 2003). Fatty acids derived from a marine crustacean Diogenes avarus (Heller) and their antiangiogenic activity. Fatty acids derived from a marine crustacean Diogenes avarus (Heller, 1865) and their antiangiogenic activity (Pathare and Indap, 2003). A New Species of the hermit crab genus Diogenes (Decapoda: Anomura: Paguroidea: Diogenidae) From Pakistan, With A Comparative Diagnosis of D-Guttatus Henderson, 1888 (Siddiqui and Mclaughlin, 2003). Diogenes pallescens whitelegge, D. gardineri Alcock and D. serenei Forest (decapoda: anomura: paguroidea: diogenidae): distinct species or morphological variants? (Mclaughlin, 2002). Population biology of the hermit crab Petrochirus diogenes (Linnaeus) (Crustacea, Decapoda) in Southern Brazil (Turra et al., 2002). Intraspecific relationships of the hermit crab Diogenes pugilator: predation and competition (Tirelli et al., 2000). Shell utilization by the hermit crabs Diogenes pugilator (roux, 1829), Paguristes eremita (linnaeus, 1767) and Pagurus Forbesii Bell, 1845 (crustacea: decapoda: anomura), in a Shallow-water community from southern Spain (Manjón-Cabeza and García, 1999). A review of the Diogenes (Crustacea, Paguridea) hermit crabs collected by Bedford and Lanchester from Singapore, and from the Skeat Expedition to the Malay Peninsula, with a description 67

7 of a new species and notes on Diogenes intermedius De Man, 1892 (Mclaughlin and Clark, 1997). Population ecology of the sand-dwelling hermit crab Diogenes nitidimanus. IV.Larval settlement (Asakura, 1991). Metamorphosis of the Hermit Crab Diogenes diogenes (Herbst) (Decapoda, Anomura) in the Laboratory (Nayak and Kakati, 1977). The following studies were conducted on genes Diogenes avarus. Influence of antiangiogenic fraction from Diogenes avarus (Heller) on fertility and implantation in mice (Pathare et al., 2004), Review of the Pakistani species of Diogenes Dana 1851 (Decapoda Anomura Paguroidea Diogenidae) (Siddiqui et al., 2004) and Fatty acids derived from a marine crustacean Diogenes avarus (Heller) and their antiangiogenic activity (Pathare and Indap, 2003). The following studies were conducted on hermit crabs of India. A new species of the hermit crab genus Paguristes Dana, 1851 (Crustacea: Decapoda: Anomura: Diogenidae) from southern India (Komai et al., 2015), A new species of the hermit crab genus Diogenes (Crustacea: Decapoda: Anomura: Diogenidae) from southern India (Komai et al., 2013), Checklist of the Porcellanidae (Crustacea: Decapoda: Anomura) of India (Prakash et al., 2013), An annotated check list of hermit crabs (Crustacea, Decapoda, Anomura) of the Persian Gulf and the Gulf of Oman with five new records and an identification key to the North Indian Ocean genera (Naderloo et al., 2012), Spatiotemporal variations of hermit crab (crustacea: decapoda) inhabiting rocky shore along Saurashtra coast, western coast of India (Vaghela and Kundu, 2012), New records of hermit crabs, Calcinus morgani (Rahayu and Forest, 1999) and Diogenes klaasi (Rahayu and Forest, 1995) (Crustacea: Anomura: Diogenidae) from India (Reshmi and Bijukumar, 2011), Spatial and Temporal Variations in Population Dynamics of Few Key Rocky Intertidal Macrofauna at Anthropogenically Influenced Intertidal shoreline (Vaghela, 2010), Habitat diversity of hermit crab Clibanarius longitarsus, India (Ramesh et al., 2009), Influence of antiangiogenic fraction from Diogenes avarus (Heller) on fertility and implantation in mice (Pathare et al., 2004), (Pathare and Indap, 2003), Metamorphosis of the Hermit Crab Diogenes diogenes (Herbst) (Decapoda, Anomura) in the Laboratory (Nayak and Kakati, 1977), Further notes on Crustacea Decapoda in the Indian Museum (Chopra and Das, 1940). Studies in hermit crabs of Porto Novo (Khan, 1979). Ecological studies on the two inter tidal hermit crabs, 68

8 Clibanarius zebra (Dana) and Clabinarius nathi (Chopra and Das) from Veraval, West Coast of India (Desai, 1986). Some aspects of physiology of the hermit crab Clibanerius arethusa (Bhale, 1982). Some aspects of physiology of hermit crab Pagurus kuikarni (Jahagirdar, 1981). Studies on The Estuarine Hermit Crab Diogenes avarus Heller (Crustacea: Decapoda: anomura) (Saravanan, 1999). Heavy Metal Toxicity in the Hermit Crab (Lyla, 1991). The following studies were conducted from Indian Ocean on some other related general topic. Crab biodiversity from Arukkattuthurai to Pasipattinam, south east coast of India (Varadharajan and Soundarapandian, 2014). BioSearch: A glimpse into marine biodiversity of Indian coastal waters (Kakodkar et al., 2013). Diversity of benthic fauna in Coleroon estuary, south east coast of India (Muniasamy et al., 2013). Comparison of intertidal biodiversity associated with natural rocky shore and sea wall: A case study from the Kerala coast, India (Ravinesh and Bijukumar, 2013). Diversity and distribution of intertidal mollusca at Saurashtra coast of Arabian Sea, India (Vaghela et al., 2013). State of Knowledge of Coastal and Marine Biodiversity of Indian Ocean Countries (Wafar et al., 2011). Changes in inter-tidal foraminifera following tsunami inundation of Indian coast (Gadi and Rajashekhar, 2007). Coastal biodiversity in the Indian Ocean: The known, the unknown and the unknowable (Keesing and Irvine, 2005). Coastal and marine biodiversity of India (Venkataraman, 2005). Distribution of certain ecological parameters and foraminiferal distribution in the depositional environment of Palk Strait, east coast of India (Gandhi, 2004). Marine protected areas (MPA) in India (Singh, 2003). Macrobenthic communities of the coastal waters of Dabhol, west coast of India (Ingole et al., 2002). The following studies were conducted from Indian Ocean on Hermit crab Digestive enzymes of two brachyuran and two anomuran land crabs from Christmas Island, Indian Ocean (Linton et al., 2014), Records of the hermit crab genus Pagurixus Melin, 1939 (Crustacea: Decapoda: Anomura: Paguridae) from Europa Island, western Indian Ocean, with descriptions of two new species (Komai and Poupin, 2013), First report of the hermit crabs Coenobita brevimanus and Coenobita rugosus (Crustacea: Decapoda: Anomura) from the Indian coast (Reshmi and Bijukumar, 2010). The hermit crabs Paguristes Dana, 1851 (Crustacea, Decapoda, Anomura, Diogenidae) from the western Indian Ocean (Rahayu, 2007). 69

9 The following related studies were done from Gujarat Coast. Habitat Preference and Population Ecology of Limpets Cellana karachiensis (Winckworth) and Siphonaria siphonaria (Sowerby) at Veraval Coast of Kathiawar Peninsula, India (Faladu et al., 2014). Ecological status of cerethium caeruleum at dwarka coast, Gujarat (India) (Gohil and Kundu, 2013). Gastropod shell utilization preferences of hermit crab Clibanarius zebra (Dana, 1852) (Diogenidae: Anomura) (Trivedi et al., 2013). Diversity and distribution of intertidal mollusca at Saurashtra coast of Arabian Sea, India (Vaghela et al., 2013). Status of the seawater quality at few industrially important coasts of Gujarat (India) off Arabian Sea (Bhadja and Kundu, 2012). Assessment of reef associated biota in the Pirotan Island, Gulf of Kachchh, Gujarat, India (Ramamoorthy et al., 2012). Spatiotemporal variations of hermit crab (crustacea: decapoda) inhabiting rocky shore along Saurashtra coast, western coast of India (Vaghela and Kundu, 2012). Impact of turbidity on intertidal macrofauna at Gopnath, Mahuva and Veraval coasts (west coast of India) (Raghunathan et al., 2003). Biological Diversity of Gujarat: Current Knowledge (Pilo et al., 1996). Ecological studies on the two inter tidal hermit crabs, Clibanarius zebra (Dana) and Clabinarius nathi (Chopra and Das) from Veraval, West Coast of India (Desai, 1986). Hermit crabs belong to Phylum Arthropoda, Subphylum Crustacea, Class malacostraca, Sub class Eumalacostraca, Order Decapoda, Sub order Pleocyemata and infra order Anomura. Decapod crustaceans have a number of behavioural and physiological features that make them appropriate subject for study, and it is relatively easy to observe them both in the nature and in laboratory. They serve as major processors of detritus in many aquatic systems. They have important role in the transfer of energy from primary producers to high-level carnivores. In some cases, they themselves are top carnivores. The Infraorder Anomura is made up of four superfamilies: Galatheoidea, Hippoidea, Lomisoidea, and Paguroidea (Kim, 2013). Hermit crabs are represented by approximately 2,002 described species worldwide (Appeltans et al., 2012). Distributed throughout the tropical, subtropical and cold seas and occupying a semi terrestrial to abyssal habitats (Rahayu and Wahyudi, 2008). Hermit crabs can commonly have encountered through mud flats, rocky shores and mangrove patches. Their uncalcified abdomens make them susceptible to higher levels of predation (Reese, 1968) and osmotic stress (Reese, 1968; Shumway, 1978) unless they can find suitable shelter. Thus, they mostly seek shelter and protection in empty 70

10 gastropod shells. Although some hermit crab species have found shelter in sessile tubes (Caine, 1980). There exists a wealth of literature on hermit crabs. This overview does not seek to be an exhaustive review of information, but rather an introduction to some of the concepts important to this study. Teoh and Chong describe that the understanding of hermit crabs especially in the aspects of ecology of principally their physiological responses and population dynamics, in relation to environmental changes such as tides, freshwater inundation, pollution, competition and predation are still scarce. There are relatively few publications related to the ecology of hermit crabs in western Indo- Pacific region despite their ecological importance to the intertidal and sublittoral communities. For this reason and in consideration of the characteristic behavior of the hermit crabs such as changing the shell as they grow, competition to acquire optimum shell fit and shell selection pattern, hermit crabs have been an attractive subject for research for ecologist (Hazlett, 1996) (Teoh, 2014a). Hermit crabs depend on shell for many significant reasons like shells provide mobile homes for them, protect from predators, maintain temperature, protect eggs, prevent water loss, salinity changes, gives protection against the wave action and avoid fragile belly to rub on a coarse sediment. In many cases, crabs must find bigger shells to grow larger (Fotheringham, 1976; Angel, 2000). Desiccation, Predation and osmotic stress are inevitable without a suitable shell (Brodie, 2005; Garcia and Mantelatto, 2001; Hamasaki et al., 2011). There are limited numbers of larger shells so a larger crab is more exposed to predation risk because of short supply of preferd shell. And if preferred shells are not available than it lead to waste of energy, leading to weak performance in competition (Kim, 2013). Inadequate shells may not be able to properly protect the soft abdomen of hermit crabs. As hermit crab grows consecutively larger, large shells are required. Proper development will not occur unless a shell is available of their size (Vance, 1972; Brodie, 1999; Kim, 2013). Hermit crabs are opportunistic detritivores. Some species are filterfeeders and antennas are very useful for finding their food from the surroundings 71

11 (Gerlach et al., 1976; Caine, 1980). However, most can be found eating detritus from the seafloor in intertidal pools, puddles, crevices and on coastal zones (Kim, 2013). Teoh described that hermit crabs are subjected to environmental disparity regulating their population distribution and abundance. Animals must endure various forms of stress caused by fluctuation in temperatures, salinity (freshwater influence), dissolved oxygen and periodic emersion and submersion caused by tides in the case of intertidal zone. Traditionally, environmental dynamics such as temperature, sediment kind, intensity of currents and topography has been largely considered to be determinant of zonations in benthic marine communities (Teoh, 2014; Haedrich et al., 1975) at soft bottom marine habitats (Hecker, 1990; Teoh, 2014) reflecting the different adaptability and specific roles of these fauna in the ecosystems. McNaughton and Wolf (1970) hypothesized that dominant species of invertebrates may play an important role in structuring the distributions of other benthic marine fauna by the fact that dominant species are able to adapt to wide range of environmental changes (Fransozo et al., 2008; Teoh, 2014). Hermit crabs are found at mud flats, sandy-rocky shore, coral reefs, and mangrove areas etc. that evidence the omnipresent adaptability of hermit crabs. Habitat partition or segregation may at times be distinct within various tropical hermit crab assemblages as macro and microhabitat preferences is in advantage of alleviating competition of resources (Abrams, 1980; Leite et al., 1998; Teoh, 2014). Amongst the abiotic factors, sediment texture invokes a relatively more important factor in the distribution and maintenance of anomuran crustacean populations (Fransozo et al., 1998) as sediment is utilized by these animals as shelter and food source (Abele, 1974; Teoh, 2014). The influence of environmental factors varies among seasons and habitats, leading to variations in the seasonal and spatial distributions of organisms and such information serve as an essential knowledge in elucidating the lifecycle of the animal s populations (Santos et al., 1994, sited from Teoh, 2014 or adapted from Teoh, 2014).3 72

12 Diel activity of hermit crabs Teoh studied the diel activity of hermit crabs. Diel movements of hermit crabs are invariably impacted by tidal periodicity and are related to their feeding behaviour, avoidance of predators, reproduction and social activities such as aggregation for shell exchange (Turra and Leite, 2000a). These activities may compensate each other on the basis of cost and benefit derived through such movements. Typically, hermit crab activity is triggered by immersion at high tide where crabs move towards foraging areas (Gherardi and Vannini, 1993) (Teoh, 2014). The large congregations of hermit crabs (clustering) are geared around for shell exchange. However, when they forage, hermit crabs are exposed to higher risk of predation (Borjesson and Szelistowski, 1989). Higher predation rates result in hermit crabs choosing heavier shells, with thicker apertures (Bertness, 1980; 1981b, d; 1982) (Rodrigue, 2000). Deposits of food sources such as carrion, algae and plant propagules may be more during spring tide and hence, greater movements during this time may yield greater energy returns (Barnes, 2003). As reported by Teoh (2014), Studies have shown the association between circatidal/circadian rhythms and distributional/activity patterns of hermit crabs (eg. Bertness, 1981a; Gherardi and Vannini, 1989, 1993, 1994; Barnes, 2001, 2003; Turra and Denadai, 2003; De Grave and Barnes, 2001). For a species, variation in migration patterns is largely related to ontogenetic stages with different habitat requirements and the increase in locomotive capabilities as the animals grow (Gibson, 2003). Large hermit crabs have been known to move faster than their smaller conspecifics which are probably a result of biomechanical consequence of muscle development and lever length (Barnes, 2003). Barnes (2003) studied short range migration of the terrestrial hermit crab, Coenobita sp. and found positive relationship between tidal range and number of active hermit crabs, and between migration distance and hermit crab size at night. Animals make use of either the ebb or flood tide current as passive transport to get from one location to the other (Tankersley et al., 2002). A huge number of investigations have been carried out on the taxonomy and geographical distribution of hermit crabs. General Crustaceans 73

13 Most animals share the common needs of obtaining food, locating shelter, and avoiding predators. Billock (2008) reported that sensory apparati are generally adapted to perceive information about the environment to meet those needs. However, the type of information most useful in completing one task may be very different from the type of information necessary to complete another. Perhaps animals focus on a key feature to scan for a resource or monitor for danger. For instance, an individual could utilize a visual search pattern when foraging, but monitor chemical information for predator odors. Narrowing the scope of simultaneous sensory processing would benefit any animal, but it is particularly important for invertebrate species that have limited neural processing capabilities. From a hermit crab s perspective, resources such as food, shelter, and potential mates can all have the same outward appearance, that of a single gastropod shell species. Perhaps other sensory information, such as chemical or tactile cues, is utilized in conjunction with, or instead of, visual information in completing various tasks. Because many resources needed by hermit crabs for survival are ephemeral, especially in the intertidal zone, these animals must evaluate the relative worth of a resource upon detection. If they spend too little, or too much time evaluating a resource, they may be missing opportunities, or unduly wasting time and energy. Unlike other decapod crustaceans that have fully hardened exoskeletons, hermit crabs have soft abdomens that make them more susceptible to predation and desiccation. This attribute requires them to protect their abdomens, usually (Billock, 2008). Bartilotti, 2010 described in his report: Tropical and temperate coastal zones are inhabited by species of benthic invertebrates, of which approximately 80% have complex life cycles with a pelagic larval phase, a vital period for gene-flow, recruitment and consequent renovation of populations (Thorson 1964, McConaugha 1992). The Phylum Crustacea is one of the largest taxa in the animal kingdom only exceeded by insects and gastropods, and the Decapoda Order is the largest one with around species (Tudge et al., 2000), a number that stills increasing (e.g. Dos Santos et al., 2008a). Most of the decapods are found in the sea or adjacent brackish waters, some species invaded the freshwater, and a small number of species occupied the terrestrial habitats (e.g. Anger 2001). The diversity of decapod species reflects the diversity in their life styles, even knowing that most decapods are benthic they can live in the floors of the oceans from the high latitudes to the tropical environments, in 74

14 mangroves, in coral reefs, polar and deep seas or hydrothermal vents. They are also a relevant part of the food web in the marine ecosystems (Bartilotti, 2010). The decapod crustacean larvae are active swimmers, that can actively regulate their vertical position in the water column, controlling the extent range and direction of their horizontal dispersal (Queiroga and Blanton 2005), maintaining a favourable position to the adequate and necessary transport (e.g. Forward et al., 1997, Christy and Morgan 1998). The transport processes are the decisive components of the supply mechanism of larvae to habitats where settlement and juvenile development will occur (e.g. Botsford 1986), separating the ontogeny in time and in space (different environments), exposing the larvae to different mortality factors (Queiroga and Blanton 2005). The understanding of temporal and spatial larval movement patterns is fundamental to study decapods ecology leading to the design of effective conservation and resource management strategies (e.g. Pittman and McAlpine 2001, Mace and Morgan 2006). The larval vertical migrations are the strategy adopted by decapods larvae for the adequate and necessary transport at a life cycle phase (e.g. Oishi and Saigusa 1997, Christy and Morgan 1998, Paula 1998, Queiroga 1998) (Bartilotti, 2010). Reports available on crustaceans has varied from anatomical studies (Evans et al., 1976; Horner et al., 1997), mating behavior (Adams and Moore, 2003; Contreras- Garduno et al., 2007), and agonistic behavior (Briffa and Elwood, 2002; Elwood et al., 2006; Hsu et al., 2006), to recognition of conspecifics (Karavanich and Atema, 1998a; Schneider et al., 2001; Gherardi and Atema, 2005; Gherardi et al., 2005), taphonomy (Shives and Dunbar, 2010), and sex-specific traits (Frix et al., 1991; Bach et al., 2006). Studies on communication and sexual differences can tie many of these topics together as some of these themes are related through communication and sexual differences (Kim, 2013). A study on spatio-temporal distribution of any species is one of the important areas of investigation in the domain of behavioral ecology. The temporal and spatial distribution of the hermit crab, Loxopagurus loxochelis from Ubatuba Bay, Brazil, has been studied (Montelatto et al., 2004). The composition and spatiotemporal distribution of Paguridae, Diogenidae and Porcellanidae in Ubatuba Bay have been investigated in detail (Fransozo et al., 1998). Spatial and temporal distribution of Horseshoe crab (Limulua polyphemus) spawning in Delaware Bay has been reported. Population 75

15 dynamics of the commensal spider crab, Jnachus phalangium (Decapoda: Maiidae) has been studied (Diesel, 1988). Bracken-Grissom et al., (2013) had studied A comprehensive and integrative reconstruction of evolutionary history for anomura (crustacea: decapoda) the findings were compared against current classifications and previous hypotheses of anomuran relationships. Many families and genera appear to be poly or paraphyletic suggesting a need for further taxonomic revisions at these levels. A divergence time analysis provides key insights into the origins of major lineages and events and the timing of morphological (body form) and ecological (habitat) transitions. Living anomuran biodiversity is the product of 2 major changes in the tempo of diversification; our initial insights suggest that the acquisition of a crab-like form did not act as a key innovation (Bracken-Grissom et al., 2013) On the other hand, Naderloo et al (2013) had studied Intertidal habitats and decapod (crustacea) diversity of Qeshm Island, a biodiversity hotspot within the Persian Gulf. This paper was published in Marine biodiversity (2013). Qualitative rapid assessments and taxonomic surveys of decapod crustaceans were carried out along the entire coastline of Qeshm Island in the Persian Gulf. Shore morphology and habitat distribution were examined. Simultaneously, decapods samples were collected from 40 selected sites. In total, 131 species from five different infraorders were identified, of which 61 were recorded for the first time from Qeshm Island and 18 species were new records for the Persian Gulf. The Brachyura possessed the highest species richness (73 species, 56 %) within the different infraorders. Among the surveyed habitats, the combined habitat rocky/cobble, occurring mainly along the south coast, had the highest species diversity. Rocky shores were dominated by Grapsus albolineatus, Metopograpsus messor, and Eriphia smithii. Cobble beaches were dominated by Leptodius exaratus, Epixanthus frontalis, Clibanarius signatus, Nanosesarma sarii, Petrolisthes spp. and Alpheus lobidens. Mudflats and mangrove forests, typical habitats of the north Coast of Qeshm Island, were bordered along their landward fringe with Nasima dotilliformis and Uca sindensis, which were accompanied by Uca iranica in some places with coarser sediments. On muddy substrate and among mangroves, Metopograpsus messor, Parasesarma persicum, Eurycarcinus orientalis, Macrophthalmus depressus, Metaplax indica, Ilyoplax stevensi, Manningis arabicum, 76

16 Opusia indica and Alpheus lobidens were the most common species. Exposed sandy beaches, mainly found on the south coast, were inhabited by Ocypode rotundata and Coenobita scaevola in high-intertidal and supralittoral zones, respectively. Emerita holthuisi occurred slightly lower in the mid-intertidal zone of relatively steep beaches where Diogenes avarus and Ryphila cancellus were found whenever the sandy beach was relatively flat. Intertidal habitats of the island are generally in relatively good condition compared with the other Persian Gulf states (Naderloo et al., 2013) Population dynamics The population structure of hermit crabs tends to show numerical dominance by females, but size dominance by males. The sex ratio is skewed towards females for entire populations (Fransozo and Mantelatto 1998, Turra and Leite 1999, Turra and Leite 2000, Litulo and Tudge 2005, Mantelatto et al., 2005), but within the same species, populations may show differences between localities (Benvenuto and Gherardi 2001), while in some populations there is no difference in the sex ratio between males and females (Garcia and Mantelatto 2001). There may also be seasonal differences in the sex ratio (Fransozo and Mantelatto 1998, Benvenuto and Gherardi 2001). Wait (2010) reported that, Hermit crab populations tend to display sexual dimorphism with males generally becoming larger than females (Harvey 1990, Wada 1999, Mantelatto and Martinelli 2001, Contreras-Garduño and Córdoba-Aguilar 2006). Proximally, this is probably due to differences in growth patterns between the sexes (Mantelatto et al., 2007), as males have faster growth rates than females, especially when suitable large shells are available (Wada et al., 1997). Ultimately sexual size dimorphism in hermit crabs could be due to increased mating success with increased size (Asakura 1995, Osorno et al., 1998, Wada 1999), either through male-male competition or through increased ability of large males to copulate successfully with smaller females (Hazlett1989). It could also be driven by female mate choice, but this is as yet unproved in hermit crabs (Contreras-Garduño and Córdoba-Aguilar 2006). Although sexual size dimorphism is common, examples can be found where congeneric species in the same environment show different size-distribution patterns (MacPherson and Raventos 2004) (Wait, 2010). Population distribution of hermit crabs 77

17 Imazu and Asakura (1994) described the spatial distribution, reproduction and shell utilization patterns of three species of common intertidal hermit crabs Pagurus geminus, Pagurus lanuginosus and Clibanarius virescens on a rocky shore at Kominato, Boso Peninsula, Japan (Teoh, 2014) The distribution of the three species greatly overlapped with P. geminus generally more widespread along the intertidal zone whereas C. virescens and P. lanuginosus occupy the lower zone. Teoh reported that, this pattern of distribution was maintained over a one-year period despite a few minor changes. Generally, female P. geminus and C. virescens inhabit farther out at lower zone than males whereas for P. lanuginosus, such a distinct difference in distribution between sexes was not seen. In a study of three common hermit crab species in a Panama rocky shore, Bertness (1981a) observed spatial separation among these species with Calcinus obscurus generally inhabit the middle to low intertidal zone, Calcinus albidigitus from the middle to high intertidal zone and Pagurus species confined at the lower intertidal zone. As mentioned by (Teoh, 2014) a study on the clustering behaviour of the hermit crab, Clibanarius laevimanus in a mangrove swamp was carried out by Gherardi and Vannini (1991) during the semilunar tide cycle in Kenya. They noted that C. laevimanus tend to form clusters around the mangrove prop roots and in the open within four metres from the mangrove fringe during every low tide and each of the cluster may consist of quiescent hundreds of individuals. The clusters of C. laevimanus would disband during flood tide and when the water recedes, crowded groups of C. laevimanus would form back the clusters, occupying the same position as well as maintaining their number, size and shape of the clusters. Gherardi and Vannini (1991) concluded that there are two main components of space utilization by C. laevimanus; firstly, is the adoption of isospatial strategy by the hermit crabs as they remained within a narrow belt along the sea-land axis of periodic submergence and emergence and secondly, is the isophasic strategy in which the clustering and the distribution of the hermit crabs are dependent on the oscillation of the water medium. The energy expenditure of locomotion for isospatial strategy is more reduced as compared to isophasic animals (Teoh, 2014) Most of the social activities of the hermit crabs are carried out during the incoming flood tide whereby hermit crabs move around, grazing on the vegetable debris and performing shell cleaning by grazing on the shell of the conspecific hermit crabs. During this phase also, the hermit crabs perform rapping motions, mating and even shell 78

18 exchange with each other or occupying new shells which are available (Snyder-Conn, 1981; Teoh, 2014). The diversity of hermit crabs at the northern edge of their occurrence is very low; in Svalbard waters only one species (Pagurus pubescens) was detected. Another species (P. bernhardus), found in northern mainland Norway, north of the Arctic Circle, is likely to extend its distribution northward as the climate warms. Where the two species co-occur, competition between them probably accounts for the smaller sizes and poorer quality shells used by P. pubescens. The composition of the mollusc shells inhabited by these crabs differs between northern Norway and Svalbard, reflecting local mollusc species pools. Hermit crab densities were significantly higher than previously reported (max. mean 10 individual. m 2 ), suggesting their increasing level of dominance in benthic communities in the studied areas. The first to report the distribution of hermit crabs among habitats, this study showed that most individuals occurred at shallow depths (5-150 m), away from glacier termini and on hard bedrock rather than on soft substrata (Balazy et al., 2015) Mantelatto et al. (2002) found no significant difference in fecundity occurred among the various seasons of the year. The results showed continuous and elevated reproduction of Paguristes tortugae, with a high reproductive potential for the population. The pattern of the frequency distribution of ovigerous females tending to bimodality may be characteristic of a population with a two-year life cycle. Branco et al., (2002) reported that the hermit crabs were more abundant during the evening than the afternoon but no difference were recorded between morning and both evening and afternoon. Females were slightly more abundant than males but the sex ratio did not differ from 1:1. Females were more abundant in the smallest size-classes (<1.8 cm) while males outnumbered females in the largest ones (>2.2 cm). The individuals of this population of Dardanus insignis have a mean cephalothoracic length of 1.89 ± 0.40 cm (range 1.00 to 3.90 cm) and a mean weight of ± g. The size distribution showed a unimodal pattern, with males being larger than ovigerous females, which, in turn, were larger than non-ovigerous females. Branco et al., (2002) had studied the Population biology and growth of the hermit crab Dardanus insignis he concluded that the recruitment was estimated to start in September and was extended to the following months. Estimates of longevity ranged from 20 to 62 months. A mortality rate of 2.21 was estimated based on the length converted catch curve. The cephalothoracic length of males and females showed, respectively, positive and negative allometry with both 79

19 cephalothoracic width and crab weight. The study investigated the prevalence, reproduction, and morphology of Athelges takanoshimensis from over 1560 hermit crab specimens collected in Hong Kong between 2000 and Among these collections, Athelges takanoshimensis was on 7% of the hermit crab Pagurus angustus and was also recorded from 5% of Pagurus hedleyi; no hermit crabs from the genus Clibanarius were infested. The male female ratio of parasitized P. angustus was approximately 3:7, in contrast to a 3:2 ratios for uninfested hosts, suggesting that parasitism has an influence on host sex ratio. Athelges takanoshimensis produced up to 5031 embryos (average brood size = 2852). Estimates of body size (head length, pereon length, and total length) were analysed as predictors of fecundity but a significant correlation was only found between brood size and pereon length. The morphology of the life history stages of A. takanoshimensis is described using scanning electron microscopy (SEM), including the first investigation of epicaridium larvae for this species. Notes on the behaviour of ovigerous females and the release of their larvae are provided, thus providing a better understanding of the natural history and morphology of A. takanoshimensis (Cericola and Williams, 2015) Most models of the impacts of climate change on the distributions of animals have focused on limits to thermal tolerances of individual species. Such bioclimatic envelope models do not consider the importance of interactions among species, each of which may respond to climate change in its own way. Hermit crabs (Paguridae) cannot exist without shells produced by gastropods. Thus, their ranges are expected to depend not only on their own physiological tolerances, but also on tolerances of gastropod species that produce shells of suitable sizes for growing crabs that use successively larger shells. To assess their potential importance to range shifts of hermit crabs, they characterized these relationships over a large area of the northern Bering Sea in May to early June. Of 1539 hermit crabs collected, Pagurus rathbuni comprised 55%, Pagurus trigonocheirus 44%, and Labidochirus splendescens 1%, with only four individuals of three other Pagurus species. P. rathbuni used shells of mostly moon snails (Naticidae); only 7 to 19% used whelk shells (Buccinidae) in the first four size classes, and 34% in the largest size class. P. trigonocheirus also used shells of mainly moon snails, but its use of whelk shells ranged from 18 to 44% in the first four size classes, and 70% in the largest size class. Densities of P. rathbuni and P. trigonocheirus varied independently (r2 = 0.08, p = 0.09, N = 36 stations). Other studies suggest that 80

20 hermit crabs obtain most of their shells from gastropods that have recently died, and that such empty shells are available for a relatively short period before being buried in sediments; thus, available shells should resemble the local pool among living gastropods. Correlation of P. rathbuni densities with densities of living gastropods with suitable shells was weak (r2 = 0.18, p b 0.01, N = 36 stations), while there was no correlation for P. trigonocheirus (r2 b 0.01, p = 0.59). Density patterns of hermit crabs within the five size classes did not correspond to densities of living gastropods with suitable shells (randomization tests of independence, all p b 0.002). These results suggest that at large spatial scales in the northern Bering Sea, near-term effects of climate change on hermit crab distributions will depend more strongly on factors other than concurrent effects on dispersion of gastropods (Peura et al., 2013) The hermit crab assemblage of Calcinus laevimanus, C. latens, and Clibanarius humilis was studied on the intertidal rocky shores of the Maldivian atolls. The species were segregated across the intertidal area, C. laevimanus and Cl humilis occurring in the midlittoral zone and supralittoral fringe, and C. latens in the infralittoral fringe and shallow subtidal. Habitat partitioning may be responsible for the coexistence of the two dimensionally closest species, C. laevimanus and C. latens. Resource partitioning probably plays the greater role in allowing C. humilis to share the same macro and microhabitats with the larger and possibly dominant C. laevimanus, since the two species occupy gastropod shells with opposite architecture. However, patterns of growth and morphology, reproductive traits, as well as the different ecological role of shell types, can negate the impact of resource overlap between these two coexisting species, since these differences may possibly have evolved under pressures other than interspecific competition for resources. Gherardi and Nardone (1997) The fecundity of three coexisting hermit crab populations (of Clibanarius antillensis, C. sclopetarius, and C. vittatus) was studied in the intertidal region of Pernambuco Islet, Sao Sebastiao Channel, south eastern Brazil. Fecundity of all species was positively correlated to the size of the individuals. Differences in egg number among species of hermit crabs were more dependent on crab shield length than on crab species, and showed the following decreasing sequence: C. sclopetarius > C. vittatus > C. antillensis. Clutch dry weight and maximum egg diameter were dependent on crab size and species, testifying particular reproductive strategies for each species. Egg size increased during embryonic 81