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Kerschbaumer M, Postl L, Sturmbauer C. Microevolutionary change in viscerocranial bones under congeneric sympatry in the Lake Tanganyikan cichlid genus Tropheus. HYDROBIOLOGIA 2021; 848:3639-3653. [PMID: 34720168 PMCID: PMC8550039 DOI: 10.1007/s10750-021-04536-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 12/21/2020] [Accepted: 02/02/2021] [Indexed: 06/13/2023]
Abstract
The endemic Lake Tanganyika cichlid genus Tropheus lives at rocky shores all around the lake and comprises six species which are subdivided into about 120 morphologically similar but color-wise distinct populations. Typically, they live without a second Tropheus species, but there are some regions where two or even three sister species live in sympatry. We previously showed that there are morphological differences concerning head shape, eye size and insertion of fins among populations living alone compared to those living in sympatry with a second Tropheus. This study goes one step further to test if sympatry affects the shape of viscerocranial bones. By means of geometric morphometrics, we compare the shape of four bones among thirteen Tropheus populations, some of which in sympatry and some living alone. We quantify patterns of shape variation and estimate morphological disparity among the four bony elements in the study species and populations. We found consistent differences in the shape of one bony element among non-sympatric and sympatric populations, besides an extensive variation in the shape of viscerocranial bones within and among species. Furthermore, sexual dimorphism in Tropheus is clearly evident in the viscerocranial bones analyzed. We suggest that the relatively subtle morphological signal in sympatric vs. non-sympatric Tropheus populations is owed to the fact that the depth segregation does not yet represent a full shift in the trophic niche, albeit our data confirm that differences in ecologically relevant traits, such as bones of the preorbital region, play an important role in the process of niche separation and in the context of explosive diversification of cichlid fishes. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s10750-021-04536-7.
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Affiliation(s)
| | - Lisbeth Postl
- Library Feldkirch, Widnau 2-4, 6800 Feldkirch, Austria
| | - Christian Sturmbauer
- Institute of Biology, University of Graz, Universitätsplatz 2, 8010 Graz, Austria
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Affiliation(s)
- Anne Le Maître
- Department of Theoretical Biology University of Vienna Vienna Austria
- PALEVOPRIM ‐ UMR 7262 CNRS INEE, Université de Poitiers Poitiers Cedex 9 France
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Van Steenberge M, Raeymaekers JAM, Hablützel PI, Vanhove MPM, Koblmüller S, Snoeks J. Delineating species along shifting shorelines: Tropheus (Teleostei, Cichlidae) from the southern subbasin of Lake Tanganyika. Front Zool 2018; 15:42. [PMID: 30459820 PMCID: PMC6234679 DOI: 10.1186/s12983-018-0287-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2018] [Accepted: 10/14/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Species delineation is particularly challenging in taxa with substantial intra-specific variation. In systematic studies of fishes, meristics and linear measurements that describe shape are often used to delineate species. Yet, little is known about the taxonomic value of these two types of morphological characteristics. Here, we used Tropheus (Teleostei, Cichlidae) from the southern subbasin of Lake Tanganyika to test which of these types of characters best matched genetic lineages that could represent species in this group of stenotypic rock-dwelling cichlids. We further investigated intra-population variation in morphology. By linking this to a proxy of a population's age, we could assess the evolutionary stability of different kinds of morphological markers. RESULTS Morphological data was collected from 570 specimens originating from 86 localities. An AFLP approach revealed the presence of five lineages in the southern subbasin: T. moorii, T. brichardi, T. sp. 'maculatus', T. sp. 'Mpimbwe' and T. sp. 'red', which we consider to represent distinct species. Although both types of morphological data supported this classification, a comparison of PST-values that describe inter-population morphological differentiation, revealed a better correspondence between the taxon delineation based on AFLP data and the patterns revealed by an analysis of meristics than between the AFLP-based taxon delineation and the patterns revealed by an analysis of shape. However, classifying southern populations of Tropheus was inherently difficult as they contained a large amount of clinal variation, both in genetic and in morphological data, and both within and among species. A scenario is put forward to explain the current-day distribution of the species and colour varieties and the observed clinal variation across the subbasin's shoreline. Additionally, we observed that variation in shape was larger in populations from shallow shores whereas populations from steep shores were more variable in meristics. This difference is explained in terms of the different timescales at which small and large scale lake level fluctuations affected populations of littoral cichlids at steep and shallow shores. CONCLUSIONS Our results showed meristics to be more evolutionary stable, and of higher taxonomic value for species delimitation in Tropheus, than linear measurements that describe shape. These results should be taken into account when interpreting morphological differences between populations of highly stenotypic species, such as littoral cichlids from the Great East African Lakes.
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Affiliation(s)
- Maarten Van Steenberge
- Vertebrates Section, Royal Museum for Central Africa, Leuvensesteenweg 13, 3080 Tervuren, Belgium
- Laboratory of Biodiversity and Evolutionary Genomics, University of Leuven, Charles Deberiotstraat 32, 3000 Leuven, Belgium
- Operational Directorate Taxonomy and Phylogeny, Royal Belgian Institute for Natural Sciences, Vautierstraat 29, 1000 Brussels, Belgium
- Institute of Biology, University of Graz, Universitätsplatz 2, 8010 Graz, Austria
| | | | - Pascal István Hablützel
- Laboratory of Biodiversity and Evolutionary Genomics, University of Leuven, Charles Deberiotstraat 32, 3000 Leuven, Belgium
- Flanders Marine Institute (VLIZ), Wandelaarkaai 7, 8400 Oostende, Belgium
| | - Maarten Pieterjan Maria Vanhove
- Laboratory of Biodiversity and Evolutionary Genomics, University of Leuven, Charles Deberiotstraat 32, 3000 Leuven, Belgium
- Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic
- Centre for Environmental Sciences, Research Group Zoology: Biodiversity & Toxicology, Hasselt University, Agoralaan Gebouw D, B-3590 Diepenbeek, Belgium
- Zoology Unit, Finnish Museum of Natural History, University of Helsinki, P.O.Box 17, FI-00014 Helsinki, Finland
| | - Stephan Koblmüller
- Institute of Biology, University of Graz, Universitätsplatz 2, 8010 Graz, Austria
| | - Jos Snoeks
- Vertebrates Section, Royal Museum for Central Africa, Leuvensesteenweg 13, 3080 Tervuren, Belgium
- Laboratory of Biodiversity and Evolutionary Genomics, University of Leuven, Charles Deberiotstraat 32, 3000 Leuven, Belgium
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Husemann M, Tobler M, McCauley C, Ding B, Danley PD. Body shape differences in a pair of closely related Malawi cichlids and their hybrids: Effects of genetic variation, phenotypic plasticity, and transgressive segregation. Ecol Evol 2017. [PMID: 28649345 PMCID: PMC5478046 DOI: 10.1002/ece3.2823] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Phenotypic differences may have genetic and plastic components. Here, we investigated the contributions of both for differences in body shape in two species of Lake Malawi cichlids using wild-caught specimens and a common garden experiment. We further hybridized the two species to investigate the mode of gene action influencing body shape differences and to examine the potential for transgressive segregation. We found that body shape differences between the two species observed in the field are maintained after more than 10 generations in a standardized environment. Nonetheless, both species experienced similar changes in the laboratory environment. Our hybrid cross experiment confirmed that substantial variation in body shape appears to be genetically determined. The data further suggest that the underlying mode of gene action is complex and cannot be explained by simple additive or additive-dominance models. Transgressive phenotypes were found in the hybrid generations, as hybrids occupied significantly more morphospace than both parentals combined. Further, the body shapes of transgressive individuals resemble the body shapes observed in other Lake Malawi rock-dwelling genera. Our findings indicate that body shape can respond to selection immediately, through plasticity, and over longer timescales through adaptation. In addition, our results suggest that hybridization may have played an important role in the diversification of Lake Malawi cichlids through creating new phenotypic variation.
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Affiliation(s)
- Martin Husemann
- Centrum für Naturkunde University of Hamburg Hamburg Germany.,Biology Department Baylor University Waco TX USA
| | - Michael Tobler
- Division of Biology Kansas State University Manhattan KS USA
| | - Cagney McCauley
- Biology Department Baylor University Waco TX USA.,Department of Biological Sciences Institute of Applied Sciences University of North Texas 282 Cr 332 Rosebud Denton TX USA
| | - Baoqing Ding
- Biology Department Baylor University Waco TX USA.,Department of Ecology and Evolutionary Biology University of Connecticut Storrs CT USA
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Ramler D, Palandačić A, Delmastro GB, Wanzenböck J, Ahnelt H. Morphological divergence of lake and stream Phoxinus of Northern Italy and the Danube basin based on geometric morphometric analysis. Ecol Evol 2017; 7:572-584. [PMID: 28116054 PMCID: PMC5243779 DOI: 10.1002/ece3.2648] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 11/01/2016] [Accepted: 11/05/2016] [Indexed: 01/31/2023] Open
Abstract
Minnows of the genus Phoxinus are promising candidates to investigate adaptive divergence, as they inhabit both still and running waters of a variety of altitudes and climatic zones in Europe. We used landmark-based geometric morphometric methods to quantify the level of morphological variability in Phoxinus populations from streams and lakes of Northern Italy and the Danube basin. We analyzed body shape differences of populations in the dorsal, lateral, and ventral planes, using a large array of landmarks and semilandmarks. As the species identification of Phoxinus on morphological characters is ambiguous, we used two mitochondrial genes to determine the genetic background of the samples and to ensure we are comparing homogenous groups. We have found significant body shape differences between habitats: Minnow populations inhabiting streams had a deeper body and caudal peduncle and more laterally inserted pectoral fins than minnows inhabiting lakes. We have also found significant body shape differences between genetic groups: Italian minnows had deeper bodies, deeper and shorter caudal peduncles, and a shorter and wider gape than both groups from the Danube. Our results show that the morphology of Phoxinus is highly influenced by habitat and that body shape variation between habitats was within the same range as between genetic groups. These morphological differences are possibly linked to different modes of swimming and foraging in the respective habitats and are likely results of phenotypic plasticity. However, differences in shape and interlandmark distances between the groups suggest that some (though few) morphometric characters might be useful for separating Phoxinus species.
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Affiliation(s)
- David Ramler
- First Zoological DepartmentMuseum of Natural History ViennaViennaAustria
- Department of Limnology and Bio‐OceanographyUniversity of ViennaViennaAustria
| | - Anja Palandačić
- First Zoological DepartmentMuseum of Natural History ViennaViennaAustria
| | | | - Josef Wanzenböck
- Research Institute for Limnology MondseeUniversity of InnsbruckMondseeAustria
| | - Harald Ahnelt
- First Zoological DepartmentMuseum of Natural History ViennaViennaAustria
- Department of Theoretical BiologyUniversity of ViennaViennaAustria
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Hata H, Ochi H. Depth and substratum differentiations among coexisting herbivorous cichlids in Lake Tanganyika. ROYAL SOCIETY OPEN SCIENCE 2016; 3:160229. [PMID: 28018609 PMCID: PMC5180107 DOI: 10.1098/rsos.160229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 10/18/2016] [Indexed: 06/06/2023]
Abstract
Cichlid fish in Lake Tanganyika represent a system of adaptive radiation in which eight ancestral lineages have diversified into hundreds of species through adaptation to various niches. However, Tanganyikan cichlids have been thought to be oversaturated, that is, the species number exceeds the number of niches and ecologically equivalent and competitively even species coexist. However, recent studies have shed light on niche segregation on a finer scale among apparently equivalent species. We observed depth and substratum preferences of 15 herbivorous cichlids from four ecomorphs (i.e. grazer, browser, scraper and scooper) on a rocky littoral slope for 14 years. Depth differentiation was detected among grazers that defended feeding territories and among browsers with feeding territories. Cichlid species having no feeding territory also showed specificity on depth and substratum, resulting in habitat segregation among species that belong to the same ecomorph. Phylogenetically close species did not occupy adjacent depths, nor the opposite depth zones. Our findings suggest that apparently equivalent species of the same ecomorph coexist parapatrically along depth on a few-metre scale, or coexist with different substratum preferences on the rocky shore, and this niche segregation may have been acquired by competition between encountering equivalent species through repetitive lake-level fluctuations.
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Affiliation(s)
- Hiroki Hata
- Graduate School of Science and Engineering, Ehime University, 2–5 Bunkyo, Matsuyama, Ehime, Japan
| | - Haruki Ochi
- 4-4-7 Higashimon-cho, Imabari 794-0033, Japan
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Hablützel PI, Grégoir AF, Vanhove MPM, Volckaert FAM, Raeymaekers JAM. Weak link between dispersal and parasite community differentiation or immunogenetic divergence in two sympatric cichlid fishes. Mol Ecol 2016; 25:5451-5466. [PMID: 27596520 DOI: 10.1111/mec.13833] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 08/18/2016] [Accepted: 08/22/2016] [Indexed: 02/03/2023]
Abstract
Geographical isolation, habitat variation and trophic specialization have contributed to a large extent to the astonishing diversity of cichlid fishes in the Great East African lakes. Because parasite communities often vary across space and environments, parasites can accompany and potentially enhance cichlid species diversification. However, host dispersal may reduce opportunities for parasite-driven evolution by homogenizing parasite communities and allele frequencies of immunity genes. To test for the relationships between parasite community variation, host dispersal and parasite-induced host evolution, we studied two sympatric cichlid species with contrasting dispersal capacities along the shores of southern Lake Tanganyika. Whereas the philopatric Tropheus moorii evolved into several genetically differentiated colour morphs, Simochromis diagramma is phenotypically rather uniform across its distribution range and shows only weak population structure. Populations of both species were infected with divergent parasite communities and harbour differentiated variant pools of an important set of immune genes, the major histocompatibility complex (MHC). The overall extent of geographical variation of parasites and MHC genes was similar between host species. This indicates that immunogenetic divergence among populations of Lake Tanganyika cichlids can occur even in species that are strongly dispersing. However, because this also includes species that are phenotypically uniform, parasite-induced evolution may not represent a key factor underlying species diversification in this system.
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Affiliation(s)
- P I Hablützel
- Laboratory of Biodiversity and Evolutionary Genomics, University of Leuven, Ch. de Bériotstraat 32, B-3000, Leuven, Belgium.
| | - A F Grégoir
- Laboratory of Aquatic Ecology, Evolution and Conservation, University of Leuven, Ch. de Bériotstraat 32, B-3000, Leuven, Belgium
| | - M P M Vanhove
- Laboratory of Biodiversity and Evolutionary Genomics, University of Leuven, Ch. de Bériotstraat 32, B-3000, Leuven, Belgium.,Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlářská 2, 611 37, Brno, Czech Republic
| | - F A M Volckaert
- Laboratory of Biodiversity and Evolutionary Genomics, University of Leuven, Ch. de Bériotstraat 32, B-3000, Leuven, Belgium
| | - J A M Raeymaekers
- Laboratory of Biodiversity and Evolutionary Genomics, University of Leuven, Ch. de Bériotstraat 32, B-3000, Leuven, Belgium.,Centre for Biodiversity Dynamics, Norwegian University of Science and Technology, N-7491, Trondheim, Norway
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Wanek KA, Sturmbauer C. Form, function and phylogeny: comparative morphometrics of Lake Tanganyika's cichlid tribe Tropheini. ZOOL SCR 2015; 44:362-373. [PMID: 27478295 PMCID: PMC4949720 DOI: 10.1111/zsc.12110] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 01/29/2015] [Indexed: 01/28/2023]
Abstract
Lake Tanganyika's cichlid fishes represent one of the most diverse species assemblages of the world. In this study we focused on the tribe Tropheini which occupies several trophic niches, mostly in rocky habitats. We analysed morphological variation of seventeen closely related species by means of geometric morphometric methods and related these data to ecological characteristics and phylogeny of the study species. It turned out that morphology mostly correlated well with ecological parameters, but not always closely with the degree of the phylogenetic relatedness of the species. Overall, body shapes in the tribe Tropheini are of great evolutionary plasticity, but variation is restricted to particular body parts: the preorbital region once again emerged as a key factor that facilitated their impressive radiation.
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Affiliation(s)
- Katrin A. Wanek
- Department of ZoologyUniversity of GrazUniversitätsplatz 2A‐8010GrazAustria
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Sefc KM, Hermann CM, Steinwender B, Brindl H, Zimmermann H, Mattersdorfer K, Postl L, Makasa L, Sturmbauer C, Koblmüller S. Asymmetric dominance and asymmetric mate choice oppose premating isolation after allopatric divergence. Ecol Evol 2015; 5:1549-62. [PMID: 25937900 PMCID: PMC4409405 DOI: 10.1002/ece3.1372] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 11/17/2014] [Indexed: 11/11/2022] Open
Abstract
Assortative mating promotes reproductive isolation and allows allopatric speciation processes to continue in secondary contact. As mating patterns are determined by mate preferences and intrasexual competition, we investigated male–male competition and behavioral isolation in simulated secondary contact among allopatric populations. Three allopatric color morphs of the cichlid fish Tropheus were tested against each other. Dyadic male–male contests revealed dominance of red males over bluish and yellow-blotch males. Reproductive isolation in the presence of male–male competition was assessed from genetic parentage in experimental ponds and was highly asymmetric among pairs of color morphs. Red females mated only with red males, whereas the other females performed variable degrees of heteromorphic mating. Discrepancies between mating patterns in ponds and female preferences in a competition-free, two-way choice paradigm suggested that the dominance of red males interfered with positive assortative mating of females of the subordinate morphs and provoked asymmetric hybridization. Between the nonred morphs, a significant excess of negative assortative mating by yellow-blotch females with bluish males did not coincide with asymmetric dominance among males. Hence, both negative assortative mating preferences and interference of male–male competition with positive assortative preferences forestall premating isolation, the latter especially in environments unsupportive of competition-driven spatial segregation.
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Affiliation(s)
- Kristina M Sefc
- Institute of Zoology, University of Graz Universitätsplatz 2, 8010, Graz, Austria
| | - Caroline M Hermann
- Institute of Zoology, University of Graz Universitätsplatz 2, 8010, Graz, Austria
| | - Bernd Steinwender
- Institute of Zoology, University of Graz Universitätsplatz 2, 8010, Graz, Austria
| | - Hanna Brindl
- Institute of Zoology, University of Graz Universitätsplatz 2, 8010, Graz, Austria
| | - Holger Zimmermann
- Institute of Zoology, University of Graz Universitätsplatz 2, 8010, Graz, Austria
| | - Karin Mattersdorfer
- Institute of Zoology, University of Graz Universitätsplatz 2, 8010, Graz, Austria
| | - Lisbeth Postl
- Institute of Zoology, University of Graz Universitätsplatz 2, 8010, Graz, Austria
| | - Lawrence Makasa
- Department of Fisheries, Lake Tanganyika Research Unit PO Box 55, Mpulungu, Zambia
| | - Christian Sturmbauer
- Institute of Zoology, University of Graz Universitätsplatz 2, 8010, Graz, Austria
| | - Stephan Koblmüller
- Institute of Zoology, University of Graz Universitätsplatz 2, 8010, Graz, Austria
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van Rijssel JC, Hoogwater ES, Kishe-Machumu MA, Reenen EV, Spits KV, van der Stelt RC, Wanink JH, Witte F. Fast adaptive responses in the oral jaw of Lake Victoria cichlids. Evolution 2014; 69:179-89. [DOI: 10.1111/evo.12561] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 10/07/2014] [Indexed: 01/08/2023]
Affiliation(s)
- Jacco C. van Rijssel
- Department of Integrative Zoology, Institute of Biology Leiden; Leiden University; P.O. Box 9505 2300 RA Leiden The Netherlands
- Naturalis Biodiversity Center; P.O. Box 9517 2300 RA Leiden The Netherlands
- Current Address: Fish Ecology and Evolution, EAWAG Center of Ecology; Evolution and Biogeochemistry; 6047 Kastanienbaum Switzerland
- Current Address: Institute of Ecology and Evolution; University of Bern; CH-3012 Bern Switzerland
| | - Ellen S. Hoogwater
- Department of Integrative Zoology, Institute of Biology Leiden; Leiden University; P.O. Box 9505 2300 RA Leiden The Netherlands
| | - Mary A. Kishe-Machumu
- Department of Integrative Zoology, Institute of Biology Leiden; Leiden University; P.O. Box 9505 2300 RA Leiden The Netherlands
- Tanzania Fisheries Research Institute (TAFIRI); 9750 Dar Es Salaam Tanzania
| | - Elize van Reenen
- Department of Integrative Zoology, Institute of Biology Leiden; Leiden University; P.O. Box 9505 2300 RA Leiden The Netherlands
| | - Kevin V. Spits
- Department of Integrative Zoology, Institute of Biology Leiden; Leiden University; P.O. Box 9505 2300 RA Leiden The Netherlands
| | - Ronald C. van der Stelt
- Department of Integrative Zoology, Institute of Biology Leiden; Leiden University; P.O. Box 9505 2300 RA Leiden The Netherlands
| | - Jan H. Wanink
- Department of Integrative Zoology, Institute of Biology Leiden; Leiden University; P.O. Box 9505 2300 RA Leiden The Netherlands
- Koeman & Bijkerk B.V; Ecological Research and Consultancy; P.O. Box 111 9750 AC Haren The Netherlands
| | - Frans Witte
- Department of Integrative Zoology, Institute of Biology Leiden; Leiden University; P.O. Box 9505 2300 RA Leiden The Netherlands
- Naturalis Biodiversity Center; P.O. Box 9517 2300 RA Leiden The Netherlands
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Hata H, Tanabe AS, Yamamoto S, Toju H, Kohda M, Hori M. Diet disparity among sympatric herbivorous cichlids in the same ecomorphs in Lake Tanganyika: amplicon pyrosequences on algal farms and stomach contents. BMC Biol 2014; 12:90. [PMID: 25359595 PMCID: PMC4228161 DOI: 10.1186/s12915-014-0090-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 10/17/2014] [Indexed: 01/23/2023] Open
Abstract
Background Lake Tanganyika, an ancient lake in the Great Rift Valley, is famous for the adaptive radiation of cichlids. Five tribes of the Cichlidae family have acquired herbivory, with five ecomorphs: grazers, browsers, scrapers, biters and scoopers. Sixteen species of the herbivorous cichlids coexist on a rocky littoral slope in the lake. Seven of them individually defend feeding territories against intruding herbivores to establish algal farms. We collected epiphyton from these territories at various depths and also gathered fish specimens. Algal and cyanobacteria community structures were analysed using the amplicon-metagenomic method. Results Based on 454-pyrosequencing of SSU rRNA gene sequences, we identified 300 phototrophic taxa, including 197 cyanobacteria, 57 bacillariophytes, and 31 chlorophytes. Algal farms differed significantly in their composition among cichlid species, even in the same ecomorph, due in part to their habitat-depth segregation. The algal species composition of the stomach contents and algal farms of each species differed, suggesting that cichlids selectively harvest their farms. The stomach contents were highly diverse, even between species in the same tribe, in the same feeding ecomorph. Conclusions In this study, the amplicon-metagenomic approach revealed food niche separation based on habitat-depth segregation among coexisting herbivorous cichlids in the same ecomorphs in Lake Tanganyika. Electronic supplementary material The online version of this article (doi:10.1186/s12915-014-0090-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hiroki Hata
- Graduate School of Science and Engineering, Ehime University, 2-5 Bunkyo, Matsuyama, Ehime, Japan.
| | - Akifumi S Tanabe
- Graduate School of Global Environmental Studies, Kyoto University, Sakyo, Kyoto, Japan. .,National Research Institute of Fisheries Science, Fisheries Research Agency, 2-12-4 Fukuura, Kanazawa, Yokohama, Japan.
| | - Satoshi Yamamoto
- Graduate School of Global Environmental Studies, Kyoto University, Sakyo, Kyoto, Japan. .,Graduate School of Human and Environmental Studies, Yoshida-Nihonmatsu, Kyoto University, Sakyo, Kyoto, Japan.
| | - Hirokazu Toju
- Graduate School of Global Environmental Studies, Kyoto University, Sakyo, Kyoto, Japan. .,Graduate School of Human and Environmental Studies, Yoshida-Nihonmatsu, Kyoto University, Sakyo, Kyoto, Japan.
| | - Masanori Kohda
- Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka, Japan.
| | - Michio Hori
- Kyoto University, Yoshida-Honmachi, Sakyo, Kyoto, Japan.
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