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Yap FC, Chen HN, Chan BKK. Host specificity and adaptive evolution in settlement behaviour of coral-associated barnacle larvae (Cirripedia: Pyrgomatidae). Sci Rep 2023; 13:9668. [PMID: 37316644 DOI: 10.1038/s41598-023-33738-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 04/18/2023] [Indexed: 06/16/2023] Open
Abstract
Coral-associated organisms often exhibit a continuum of host specificities. We do not know whether the variation in host specificity is related to the settlement organs or preferential settlement behaviours of the larvae. We examined the morphology of attachment discs, the settlement and metamorphosis of coral barnacles-Pyrgoma cancellatum (lives in a single coral species), Nobia grandis (two families of corals), and Armatobalanus allium (six families of corals). Our results revealed that the attachment organ of all three species are spear-shaped with sparse villi, indicating that the morphology of the attachment organs does not vary among species with different host specificities. Larvae of P. cancellatum and N. grandis only settle on their specific hosts, suggesting that chemical cues are involved in the settlement. Cyprids of N. grandis display close searching behaviour before settlement. Cyprids of P. cancellatum settle immediately on their specific host corals, without any exploratory behaviour. The host specificity and exploratory behaviours of coral barnacle cyprids are results of adaptive evolution. We argue that there is a trade-off between exploration and energy conservation for metamorphosis processes. Coral barnacle metamorphosis is longer when compared to free-living species, likely because it involves the development of a tube-shaped base on the coral surface.
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Affiliation(s)
- Fook-Choy Yap
- Biodiversity Research Center, Academia Sinica, Taipei, 11529, Taiwan
- Graduate School, University of Nottingham Malaysia, Jalan Broga, Selangor, 43500, Semenyih, Malaysia
| | - Hsi-Nien Chen
- Chemistry and Environmental Research Laboratory, Taiwan Power Research Institute, New Taipei City, 238, Taiwan
| | - Benny K K Chan
- Biodiversity Research Center, Academia Sinica, Taipei, 11529, Taiwan.
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2
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Yap F, Høeg JT, Chan BKK. Living on fire: Deactivating fire coral polyps for larval settlement and symbiosis in the fire coral-associated barnacle Wanella milleporae (Thoracicalcarea: Wanellinae). Ecol Evol 2022; 12:e9057. [PMID: 35813926 PMCID: PMC9254672 DOI: 10.1002/ece3.9057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 06/07/2022] [Accepted: 06/09/2022] [Indexed: 12/02/2022] Open
Abstract
Symbiosis is increasingly recognized as being an important component in marine systems, and many such relationships are initiated when free-swimming larvae of one partner settle and become sedentary on a host partner. Therefore, several crucial questions emerge such as the larva's mechanism of locating a host, selection of substratum and finally settlement on the surface of its future partner. Here, we investigated these mechanisms by studying how larvae of the fire coral-associated barnacle Wanella milleporae move, settle and establish symbiosis with their host, Millepora tenera. Cyprids of W. milleporae possess a pair of specialized antennules with bell-shaped attachment discs that enable them to explore and settle superficially on the hostile surface of the fire coral. Intriguingly, the stinging polyps of the fire coral remain in their respective pores when the cyprids explore the fire coral surface. Even when cyprids come into contact with the nematocysts on the extended stinging polyps during the exploratory phase, no immobilization effects against the cyprids were observed. The exploratory phase of Wanella cyprids can be divided into a sequence of wide searching (large step length and high walking speed), close searching (small step length and low speed) and inspection behavior, eventually resulting in permanent settlement and metamorphosis. After settlement, xenogeneic interactions occur between the fire coral and the newly metamorphosed juvenile barnacle. This involved tissue necrosis and regeneration in the fire coral host, leading to a callus ring structure around the juvenile barnacle, enhancing survival rate after settlement. The complex exploratory and settlement patterns and interactions documented here represent a breakthrough in coral reef symbiosis studies to show how invertebrates start symbiosis with fire corals.
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Affiliation(s)
- Fook‐Choy Yap
- Biodiversity Research CenterAcademia SinicaNangangTaiwan
- Present address:
Department of Biological Science, Faculty of ScienceUniversiti Tunku Abdul Rahman, Jalan Universiti, Bandar BaratPerakMalaysia
| | - Jens T. Høeg
- Department of Biology, Marine Biological SectionUniversity of CopenhagenCopenhagenDenmark
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Dreyer N, Tsai PC, Olesen J, Kolbasov GA, Høeg JT, Chan BKK. Independent and adaptive evolution of phenotypic novelties driven by coral symbiosis in barnacle larvae. Evolution 2021; 76:139-157. [PMID: 34705275 DOI: 10.1111/evo.14380] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 09/28/2021] [Accepted: 10/02/2021] [Indexed: 11/29/2022]
Abstract
The invasion of novel habitats is recognized as a major promotor of adaptive trait evolution in animals. We tested whether similar ecological niches entail independent and adaptive evolution of key phenotypic structures related to larval host invasion in distantly related taxa. We use disparately related clades of coral barnacles as our model system (Acrothoracica: Berndtia and Thoracica: Pyrgomatidae). We analyze the larval antennular phenotypes and functional morphologies facilitating host invasion. Extensive video recordings show that coral host invasion is carried out exclusively by cypris larvae with spear-shaped antennules. These first exercise a series of complex probing behaviors followed by repeated antennular penetration of the soft host tissues, which subsequently facilitates permanent invasion. Phylogenetic mapping of larval form and function related to niche invasion in 99 species of barnacles (Thecostraca) compellingly shows that the spear-phenotype is uniquely associated with corals and penetrative behaviors. These features evolved independently in the two coral barnacle clades and from ancestors with fundamentally different antennular phenotypes. The larval host invasion system in coral barnacles likely evolved adaptively across millions of years for overcoming challenges associated with invading and entering demanding coral hosts. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Niklas Dreyer
- Department of Life Science, National Taiwan Normal University, Taiwan.,Biodiversity Program, Taiwan International Graduate Program, Academia Sinica, Taipei.,Biodiversity Research Center, Academia Sinica, Taipei 115, Taiwan.,Natural History Museum of Denmark, University of Copenhagen, Universitetsparken 15, Kobenhavn, DK-2100, Denmark
| | - Pei-Che Tsai
- Institute of Ecology and Evolutionary Biology, National Taiwan University, Taiwan
| | - Jørgen Olesen
- Natural History Museum of Denmark, University of Copenhagen, Universitetsparken 15, Kobenhavn, DK-2100, Denmark
| | - Gregory A Kolbasov
- White Sea Biological Station, Biological Faculty of Moscow State University, Moscow, 119899, Russia
| | - Jens T Høeg
- Marine Biological Section, Department of Biology, University of Copenhagen, Universitetsparken 4, Kobenhavn, DK-2100, Denmark
| | - Benny K K Chan
- Biodiversity Research Center, Academia Sinica, Taipei 115, Taiwan
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Chan BKK, Dreyer N, Gale AS, Glenner H, Ewers-Saucedo C, Pérez-Losada M, Kolbasov GA, Crandall KA, Høeg JT. The evolutionary diversity of barnacles, with an updated classification of fossil and living forms. Zool J Linn Soc 2021. [DOI: 10.1093/zoolinnean/zlaa160] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Abstract
We present a comprehensive revision and synthesis of the higher-level classification of the barnacles (Crustacea: Thecostraca) to the genus level and including both extant and fossils forms. We provide estimates of the number of species in each group. Our classification scheme has been updated based on insights from recent phylogenetic studies and attempts to adjust the higher-level classifications to represent evolutionary lineages better, while documenting the evolutionary diversity of the barnacles. Except where specifically noted, recognized taxa down to family are argued to be monophyletic from molecular analysis and/or morphological data. Our resulting classification divides the Thecostraca into the subclasses Facetotecta, Ascothoracida and Cirripedia. The whole class now contains 14 orders, 65 families and 367 genera. We estimate that barnacles consist of 2116 species. The taxonomy is accompanied by a discussion of major morphological events in barnacle evolution and justifications for the various rearrangements we propose.
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Affiliation(s)
- Benny K K Chan
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan
| | - Niklas Dreyer
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
- Biodiversity Program, Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan
- Natural History Museum of Denmark, Invertebrate Zoology, University of Copenhagen, Universitetsparken, Copenhagen, Denmark
| | - Andy S Gale
- School of Earth and Environmental Sciences, University of Portsmouth, Portsmouth, UK
- Department of Earth Sciences, The Natural History Museum, London, UK
| | - Henrik Glenner
- Marine Biodiversity Group, Department of Biology, University of Bergen, Bergen, Norway
- Center for Macroecology, Evolution and Climate, GLOBE Institute, University of Copenhagen, Copenhagen, Denmark
| | | | - Marcos Pérez-Losada
- Computational Biology Institute, Department of Biostatistics and Bioinformatics, George Washington University, Washington, DC, USA
- CIBIO-InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Vairão, Portugal
| | - Gregory A Kolbasov
- White Sea Biological Station, Biological Faculty of Moscow State University, Moscow, Russia
| | - Keith A Crandall
- Computational Biology Institute, Department of Biostatistics and Bioinformatics, George Washington University, Washington, DC, USA
- Department of Invertebrate Zoology, US National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
| | - Jens T Høeg
- Marine Biology Section, Department of Biology, University of Copenhagen, Copenhagen, Denmark
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Zardus JD. A Global Synthesis of the Correspondence Between Epizoic Barnacles and Their Sea Turtle Hosts. Integr Org Biol 2021; 3:obab002. [PMID: 33937627 PMCID: PMC8077887 DOI: 10.1093/iob/obab002] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Barnacles that are obligate epizoites of sea turtles are not parasites in the traditional sense. However, they can impair their hosts in some instances, disqualifying the association as strictly commensal. Characterizing these interactions requires knowing which epibionts pair with which hosts, but records of barnacles from sea turtles are scattered and symbiont/host match-ups remain equivocal. The objective of this study was to collate global records on the occurrence of barnacles with sea turtles and describe each species pair quantitatively. Records reporting barnacles with sea turtles were searched spanning the last 167 years, including grey literature, and findings were enumerated for 30,580 individual turtles to evaluate prevalence. The data were summarized globally as well as subdivided across six geographic regions to assess constancy of the affiliations. Patterns of partnering were visualized by hierarchical clustering analysis of percent occurrence values for each barnacle/turtle pair and the relative selectivity of each symbiont and susceptibility of each host were evaluated. After adjusting for synonymies and taxonomic inaccuracies, the occurrence of 16 nominal species of barnacles was recorded from all 7 extant sea turtle species. Mostly, barnacles were not specific to single turtle species, partnering on average with three hosts each. Neither were barnacles entirely host-consistent among regions. Three barnacles were common to all sea turtles except leatherbacks. The most common, widespread, and least selective barnacle was Chelonibia testudinaria, the only symbiont of all turtles. Excluding single-record occurrences, the barnacle Stomatolepas transversa was the only single-host associate of any hard-shell sea turtle (the green sea turtle) and Platylepas coriacea and Stomatolepas dermochelys were exclusive associates of leatherback sea turtles. Green sea turtles were the most vulnerable to epibiosis, hosting 13 barnacle species and Kemp’s ridley sea turtles were the least, hosting three. Geographically, there was an average of nine barnacle species per world region, with diversity highest in the Pacific Ocean (12 species) and lowest in the Mediterranean Sea (6 species). It is paradoxical that the flexibility of barnacles for multiple host species contrasts with their overall strict specificity for sea turtles, with each symbiont occupying a virtually unique suite of turtle hosts.
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Affiliation(s)
- John D Zardus
- Department of Biology, The Citadel, 171 Moultrie Street, Charleston, SC 29409, USA
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Dreyer N, Zardus JD, Høeg JT, Olesen J, Yu MC, Chan BKK. How whale and dolphin barnacles attach to their hosts and the paradox of remarkably versatile attachment structures in cypris larvae. ORG DIVERS EVOL 2020. [DOI: 10.1007/s13127-020-00434-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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7
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Yu MC, Dreyer N, Kolbasov GA, Høeg JT, Chan BKK. Sponge symbiosis is facilitated by adaptive evolution of larval sensory and attachment structures in barnacles. Proc Biol Sci 2020; 287:20200300. [PMID: 32396804 PMCID: PMC7287368 DOI: 10.1098/rspb.2020.0300] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Symbiotic relations and range of host usage are prominent in coral reefs and crucial to the stability of such systems. In order to explain how symbiotic relations are established and evolve, we used sponge-associated barnacles to ask three questions. (1) Does larval settlement on sponge hosts require novel adaptations facilitating symbiosis? (2) How do larvae settle and start life on their hosts? (3) How has this remarkable symbiotic lifestyle involving many barnacle species evolved? We found that the larvae (cyprids) of sponge-associated barnacles show a remarkably high level of interspecific variation compared with other barnacles. We document that variation in larval attachment devices are specifically related to properties of the surface on which they attach and metamorphose. Mapping of the larval and sponge surface features onto a molecular-based phylogeny showed that sponge symbiosis evolved separately at least three times within barnacles, with the same adaptive features being found in all larvae irrespective of phylogenetic relatedness. Furthermore, the metamorphosis of two species proceeded very differently, with one species remaining superficially on the host and developing a set of white calcareous structures, the other embedding itself into the live host tissue almost immediately after settlement. We argue that such a high degree of evolutionary flexibility of barnacle larvae played an important role in the successful evolution of complex symbiotic relationships in both coral reefs and other marine systems.
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Affiliation(s)
- Meng-Chen Yu
- Doctoral Degree Program in Marine Biotechnology, National Sun Yat-sen University and Academia Sinica, Kaohsiung 80424, Taiwan.,Biodiversity Research Center, Academia Sinica, Taipei 11529, Taiwan
| | - Niklas Dreyer
- Biodiversity Research Center, Academia Sinica, Taipei 11529, Taiwan.,Department of Life Science, National Taiwan Normal University, Taipei, Taiwan.,Biodiversity Program, Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan.,Natural History Museum of Denmark, University of Copenhagen, Universitetsparken 15, DK-2100 Copenhagen, Denmark
| | | | - Jens Thorvald Høeg
- Department of Biology, Marine Biological Section, University of Copenhagen, Universitetsparken 4, DK-2100 Copenhagen, Denmark
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Kotsiri M, Protopapa M, Roumelioti GM, Economou-Amilli A, Efthimiadou EK, Dedos SG. Probing the settlement signals of Amphibalanus amphitrite. BIOFOULING 2018; 34:492-506. [PMID: 29792352 DOI: 10.1080/08927014.2018.1465566] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 04/11/2018] [Indexed: 06/08/2023]
Abstract
To achieve their reproductive potential, barnacles combine tactile exploration of surface structural properties and integration of cellular signals originating from their antennular sensory setae within a developmentally defined, temporally narrow window of settlement opportunity. Behavioural assays with cyprids coupled with biometric analysis of scanning electron microscopy-acquired images in the presence of specific chemical compounds were used to investigate how settlement on a substratum is altered in response to the presence of these compounds. It is shown that impeding tactile exploration, altering cellular signalling and/or inducing malformations of anatomical features of the antennular sensory setae can disrupt the settlement behaviour of the model barnacle species Amphibalanus amphitrite. It is concluded that surface exploration by the cyprids relies on mechanical and nociception-related and calcium-mediated signals while a protein kinase C signalling cascade controls the timely metamorphosis of the cyprids to sessile juveniles.
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Affiliation(s)
- Mado Kotsiri
- a Department of Biology , National and Kapodistrian University of Athens , Athens , Greece
| | - Maria Protopapa
- a Department of Biology , National and Kapodistrian University of Athens , Athens , Greece
| | | | - Athena Economou-Amilli
- a Department of Biology , National and Kapodistrian University of Athens , Athens , Greece
| | - Eleni K Efthimiadou
- b Department of Chemistry , National and Kapodistrian University of Athens , Athens , Greece
| | - Skarlatos G Dedos
- a Department of Biology , National and Kapodistrian University of Athens , Athens , Greece
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Dreyer N, Olesen J, Dahl RB, Kan Chan BK, Høeg JT. Sex-specific metamorphosis of cypris larvae in the androdioecious barnacle Scalpellum scalpellum (Crustacea: Cirripedia: Thoracica) and its implications for the adaptive evolution of dwarf males. PLoS One 2018; 13:e0191963. [PMID: 29466363 PMCID: PMC5842884 DOI: 10.1371/journal.pone.0191963] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 01/15/2018] [Indexed: 11/24/2022] Open
Abstract
Androdioecy (co-existence of hermaphrodites and dwarf males) is a fascinating yet poorly understood phenomenon. The pedunculated barnacle Scalpellum scalpellum is an emerging model species for the system. In S. scalpellum, dwarf males and hermaphrodites are very different in adult morphology (e.g., in feeding structures and reproductive organs), but they share the same larval development with nauplii followed by cypris larvae. Recently, it was found that S. scalpellum cypris larvae display both genetic and environmental sex determination, but no detailed morphological study has yet investigated how the settled cypris larvae differ subsequent to settlement. This study investigates the morphological aspects of the onset of sex determination in the cyprids of S. scalpellum by examining their metamorphosis into either dwarf males or hermaphrodites under laboratory conditions. This study emphasizes morphological differences, such as size and shape of primordial shell plates, development of a flexible peduncle and of thoracopods. It was shown that the cypris larvae start to differ already one day after settlement on either a hydroid (leading to hermaphrodites) or an adult hermaphrodite (leading to dwarf males). Dwarf males gradually developed an ovoid body shape and two pairs of circular scutal and tergal primordia. Such cyprids developed neither a carina nor any peduncle or cirri for feeding. The study concludes that the dwarf males of S. scalpellum are not just hermaphrodites arrested early in development. This entails that dwarf males constitute their own separate developmental pathways and points to S. scalpellum dwarf males being more specialized than previously stated. Finally, the study compares differences in dwarf male morphology between S. scalpellum with two other androdioecious species with less specialized dwarf males and use this to discuss evolutionary implications for the adaptive evolution of dwarf males across the Cirripedia.
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Affiliation(s)
- Niklas Dreyer
- Natural History Museum of Denmark, Section for Biosystematics, Copenhagen, Denmark
| | - Jørgen Olesen
- Natural History Museum of Denmark, Section for Biosystematics, Copenhagen, Denmark
| | - Rikke Beckmann Dahl
- Natural History Museum of Denmark, Section for Evogenomics, Copenhagen, Denmark
| | | | - Jens Thorvald Høeg
- Department of Biology, Marine Biological Section, University of Copenhagen, Copenhagen, Denmark
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Chan BKK, Sari A, Høeg JT. Cirripede Cypris Antennules: How Much Structural Variation Exists Among Balanomorphan Species from Hard-Bottom Habitats? THE BIOLOGICAL BULLETIN 2017; 233:135-143. [PMID: 29373061 DOI: 10.1086/695689] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Barnacle cypris antennules are important for substratum attachment during settlement and on through metamorphosis from the larval stage to sessile adult. Studies on the morphology of cirripede cyprids are mostly qualitative, based on descriptions from images obtained using a scanning electron microscope (SEM). To our knowledge, our study is the first to use scanning electron microscopy to quantify overall structural diversity in cypris antennules by measuring 26 morphological parameters, including the structure of sensory organs. We analyzed cyprids from seven species of balanomorphan barnacles inhabiting rocky shore communities; for comparison, we also included a sponge-inhabiting balanomorphan and a verrucomorphan species. Multivariate analysis of the structural parameters resulted in two distinct clusters of species. From nonmetric multidimensional scaling plots, the sponge-inhabiting Balanus spongicola and Verruca stroemia formed one cluster, while the other balanomorphan species, all from hard bottoms, grouped together in the other cluster. The shape of the attachment disk on segment 3 is the key parameter responsible for the separation into two clusters. The present results show that species from a coastal hard-bottom habitat may share a nearly identical antennular structure that is distinct from barnacles from other habitats, and this finding supports the fact that such species also have rather similar reactions to substratum cues during settlement. Any differences that may be found in settlement biology among such species must therefore be due either to differences in the properties of their adhesive mechanisms or to the way that sensory stimuli are detected by virtually identical setae and processed into settlement behavior by the cyprid.
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Key Words
- AD, attachment disk
- ANOSIM, analysis of similarity
- RDS, radial disk setae
- RDS-5, radial disk seta 5
- SIMPER, similarity percentage
- TS-A+B, terminal setae A and B
- TS-D, terminal seta D
- as2, second antennular segment
- as3, third antennular segment
- nMDS, nonmetric multidimensional scaling
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