{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,14]],"date-time":"2026-10-14T11:02:47Z","timestamp":1791975767982,"version":"4.4.0"},"reference-count":38,"publisher":"National Academy of Sciences","issue":"7","content-domain":{"domain":["www.pnas.org"],"crossmark-restriction":true},"short-container-title":["Proc. Natl. Acad. Sci. U.S.A."],"published-print":{"date-parts":[[2009,2,17]]},"abstract":"<jats:p>\n                    Genetic data has become an essential part of ecological studies, because the analyses of diversity within and among natural populations may grant access to previously overlooked ecological and evolutionary causalities, especially among cryptic species. Here, we present an example of how phylogenetic analysis of molecular data obtained within a DNA barcoding study, in combination with morphological and ecological data from the field and laboratory experiments, unraveled a striking predator-prey interaction between aquatic organisms. The \u201ccrown of thorns,\u201d a conspicuous morphological feature among water fleas of the\n                    <jats:italic>Daphnia atkinsoni<\/jats:italic>\n                    species complex (Crustacea: Cladocera), is considered to represent a species-specific trait. However, our study, initiated by the analysis of sequence variation in 2 mitochondrial genes, shows that this feature is phenotypically plastic and is induced by chemical cues released by\n                    <jats:italic>Triops cancriformis<\/jats:italic>\n                    , the tadpole shrimp (Notostraca). The trait acts as an effective antipredator defense, and is found in several\n                    <jats:italic>Daphnia<\/jats:italic>\n                    lineages coexisting with notostracans. These facts suggest that the \u201ccrown of thorns\u201d evolved in coexistence with this ancient predator group.\n                  <\/jats:p>","DOI":"10.1073\/pnas.0808075106","type":"journal-article","created":{"date-parts":[[2009,1,14]],"date-time":"2009-01-14T22:42:49Z","timestamp":1231972969000},"page":"2248-2252","update-policy":"https:\/\/doi.org\/10.1073\/pnas.cm10313","source":"Crossref","is-referenced-by-count":117,"title":["A \u201ccrown of thorns\u201d is an inducible defense that protects\n                    <i>Daphnia<\/i>\n                    against an ancient predator"],"prefix":"10.1073","volume":"106","author":[{"given":"Adam","family":"Petrusek","sequence":"first","affiliation":[{"name":"Department of Ecology, Faculty of Science, Charles University, Vini\u010dn\u00e1 7, CZ-12844 Prague, Czech Republic;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ralph","family":"Tollrian","sequence":"additional","affiliation":[{"name":"Animal Ecology, Evolution and Biodiversity, Ruhr-University Bochum, Universit\u00e4tsstrasse 150 \/ND05, D-44780 Bochum, Germany;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Klaus","family":"Schwenk","sequence":"additional","affiliation":[{"name":"Department of Ecology and Evolution, Johann Wolfgang Goethe-University, Siesmayerstrasse 70, D-60054 Frankfurt am Main, Germany; and"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Andreas","family":"Haas","sequence":"additional","affiliation":[{"name":"Departments of Biology II and Evolutionary Ecology, and GeoBio-Center, Ludwig-Maximilians University Munich, Grosshaderner Strasse 2, D-82152 Planegg-Martinsried, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christian","family":"Laforsch","sequence":"additional","affiliation":[{"name":"Departments of Biology II and Evolutionary Ecology, and GeoBio-Center, Ludwig-Maximilians University Munich, Grosshaderner Strasse 2, D-82152 Planegg-Martinsried, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"341","published-online":{"date-parts":[[2009,2,17]]},"reference":[{"key":"e_1_3_3_1_2","doi-asserted-by":"crossref","DOI":"10.1515\/9780691228198","volume-title":"The Ecology and Evolution of Inducible Defenses","author":"Tollrian R","year":"1999","unstructured":"R Tollrian, CD Harvell The Ecology and Evolution of Inducible Defenses (Princeton Univ Press, Princeton, 1999)."},{"key":"e_1_3_3_2_2","doi-asserted-by":"crossref","first-page":"177","DOI":"10.1515\/9780691228198-013","volume-title":"The Ecology and Evolution of Inducible Defenses","author":"Tollrian R","year":"1999","unstructured":"R Tollrian, SI Dodson The Ecology and Evolution of Inducible Defenses, eds R Tollrian, CD Harvell (Princeton Univ Press, Princeton), pp. 177\u2013202 (1999)."},{"key":"e_1_3_3_3_2","first-page":"486","volume-title":"Fauna Iberica","author":"Alonso M","year":"1996","unstructured":"M Alonso, Crustacea, Branchiopoda. Fauna Iberica, eds MA Ramos, et al. (Museo Nacional de Ciencias Naturales \u2013 Consejo Superior de Investigaciones Cient\u00edficas, Madrid) Vol 7, 486, in Spanish. (1996)."},{"key":"e_1_3_3_4_2","first-page":"376","volume-title":"Cladocera: The genus Daphnia (including Daphniopsis)","author":"Benzie JAH","year":"2005","unstructured":"JAH Benzie Cladocera: The genus Daphnia (including Daphniopsis) (Kenobi Productions, Backhuys Publishers, Ghent, Leiden), pp. 376 (2005)."},{"key":"e_1_3_3_5_2","first-page":"47","article-title":"Nota sobre algunes Ctenodaphnia de la Pen\u00ednsula Ib\u00e8rica [Note on some Ctenodaphnia of the Iberian Peninsula]","volume":"45","author":"Alonso M","year":"1980","unstructured":"M Alonso, Nota sobre algunes Ctenodaphnia de la Pen\u00ednsula Ib\u00e8rica [Note on some Ctenodaphnia of the Iberian Peninsula]. Butl Inst Catalana Hist Nat 45, 47\u201353, in Catalan. (1980).","journal-title":"Butl Inst Catalana Hist Nat"},{"key":"e_1_3_3_6_2","first-page":"85","article-title":"New Triopsids (Crustacea, Notostraca) from the Upper Triassic of Frankonia, Germany","volume":"5","author":"Kelber K-P","year":"1998","unstructured":"K-P Kelber, New Triopsids (Crustacea, Notostraca) from the Upper Triassic of Frankonia, Germany. Hallesches Jb Geowiss B, Beih 5, 85\u201386 (1998).","journal-title":"Hallesches Jb Geowiss B, Beih"},{"key":"e_1_3_3_7_2","doi-asserted-by":"publisher","DOI":"10.1023\/A:1017584928657"},{"key":"e_1_3_3_8_2","doi-asserted-by":"publisher","DOI":"10.1007\/s10750-004-5033-6"},{"key":"e_1_3_3_9_2","doi-asserted-by":"publisher","DOI":"10.1098\/rsbl.2003.0025"},{"key":"e_1_3_3_10_2","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pbio.0020354"},{"key":"e_1_3_3_11_2","doi-asserted-by":"publisher","DOI":"10.1080\/10635150500354878"},{"key":"e_1_3_3_12_2","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.0700466104"},{"key":"e_1_3_3_13_2","article-title":"The scale of divergence: A phylogenetic appraisal of intercontinental allopatric speciation in a passively dispersed freshwater zooplankton genus","author":"Adamowicz SJ","year":"2008","unstructured":"SJ Adamowicz, JK Colbourne, JDS Witt, PDN Hebert, The scale of divergence: A phylogenetic appraisal of intercontinental allopatric speciation in a passively dispersed freshwater zooplankton genus. Mol Phylogenet Evol, in press. (2008).","journal-title":"Mol Phylogenet Evol"},{"key":"e_1_3_3_14_2","doi-asserted-by":"publisher","DOI":"10.1098\/rstb.1996.0028"},{"key":"e_1_3_3_15_2","first-page":"82","article-title":"Gronlads Ferskvandsentomostraca. I. Phyllopoda branchiopoda et cladocera. [Freshwater Entomostraca of Greenland. I. Phyllopoda branchiopoda and cladocera.]","volume":"56","author":"Wesenberg-Lund C","year":"1895","unstructured":"C Wesenberg-Lund, Gronlads Ferskvandsentomostraca. I. Phyllopoda branchiopoda et cladocera. [Freshwater Entomostraca of Greenland. I. Phyllopoda branchiopoda and cladocera.]. Vidensk Medd naturhist Foren Kjobenhavn 56, 82\u2013173 (1895).","journal-title":"Vidensk Medd naturhist Foren Kjobenhavn"},{"key":"e_1_3_3_16_2","first-page":"303","article-title":"The fresh-water Entomostraca of Cape Province","volume":"15","author":"Sars GO","year":"1916","unstructured":"GO Sars, The fresh-water Entomostraca of Cape Province. Ann S Afr Mus 15, 303\u2013351 (1916).","journal-title":"Ann S Afr Mus"},{"key":"e_1_3_3_17_2","doi-asserted-by":"publisher","DOI":"10.2307\/1467813"},{"key":"e_1_3_3_18_2","first-page":"367","volume-title":"Predation: Direct and indirect impacts on aquatic communities","author":"Kerfoot WC","year":"1987","unstructured":"WC Kerfoot, M Lynch Predation: Direct and indirect impacts on aquatic communities, eds WC Kerfoot, A Sih (Univ Press of New England, Hanover), pp. 367\u2013378 (1987)."},{"key":"e_1_3_3_19_2","doi-asserted-by":"publisher","DOI":"10.1038\/195722a0"},{"key":"e_1_3_3_20_2","first-page":"447","article-title":"Larvicidal efficiency of aquatic predators: A perspective for mosquito biocontrol","volume":"45","author":"Kumar R","year":"2006","unstructured":"R Kumar, JS Hwang, Larvicidal efficiency of aquatic predators: A perspective for mosquito biocontrol. Zool Stud 45, 447\u2013466 (2006).","journal-title":"Zool Stud"},{"key":"e_1_3_3_21_2","doi-asserted-by":"publisher","DOI":"10.1007\/s10750-006-0259-0"},{"key":"e_1_3_3_22_2","doi-asserted-by":"publisher","DOI":"10.1023\/A:1021350802144"},{"key":"e_1_3_3_23_2","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.0404860101"},{"key":"e_1_3_3_24_2","doi-asserted-by":"publisher","DOI":"10.2307\/1938331"},{"key":"e_1_3_3_25_2","doi-asserted-by":"publisher","DOI":"10.1046\/j.1365-2427.2000.00642.x"},{"key":"e_1_3_3_26_2","doi-asserted-by":"publisher","DOI":"10.1098\/rspb.2000.1218"},{"key":"e_1_3_3_27_2","doi-asserted-by":"publisher","DOI":"10.1006\/mpev.1996.0045"},{"key":"e_1_3_3_28_2","doi-asserted-by":"publisher","DOI":"10.1111\/j.1095-8312.2006.00687.x"},{"key":"e_1_3_3_29_2","doi-asserted-by":"publisher","DOI":"10.1023\/A:1009939901198"},{"key":"e_1_3_3_30_2","doi-asserted-by":"publisher","DOI":"10.1093\/nar\/22.22.4673"},{"key":"e_1_3_3_31_2","doi-asserted-by":"publisher","DOI":"10.1093\/molbev\/msm092"},{"key":"e_1_3_3_32_2","doi-asserted-by":"publisher","DOI":"10.2307\/2413663"},{"key":"e_1_3_3_33_2","doi-asserted-by":"publisher","DOI":"10.1093\/bioinformatics\/14.9.817"},{"key":"e_1_3_3_34_2","volume-title":"PAUP*. Phylogenetic Analysis Using Parsimony (*and Other Methods)","author":"Swofford DL","year":"2002","unstructured":"DL Swofford PAUP*. Phylogenetic Analysis Using Parsimony (*and Other Methods) (Sinauer Associates, Sunderland, 2002)."},{"key":"e_1_3_3_35_2","doi-asserted-by":"publisher","DOI":"10.1093\/bioinformatics\/btg180"},{"key":"e_1_3_3_36_2","doi-asserted-by":"publisher","DOI":"10.1007\/s004420051026"},{"key":"e_1_3_3_37_2","doi-asserted-by":"publisher","DOI":"10.1038\/43425"},{"key":"e_1_3_3_38_2","first-page":"887","volume-title":"Biometry","author":"Sokal RR","year":"1995","unstructured":"RR Sokal, FJ Rohlf Biometry (Freeman, 3rd Ed, New York), pp. 887 (1995).","edition":"3"}],"container-title":["Proceedings of the National Academy of Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/pnas.org\/doi\/pdf\/10.1073\/pnas.0808075106","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,5,23]],"date-time":"2023-05-23T12:05:24Z","timestamp":1684843524000},"score":1,"resource":{"primary":{"URL":"https:\/\/pnas.org\/doi\/full\/10.1073\/pnas.0808075106"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2009,2,17]]},"references-count":38,"journal-issue":{"issue":"7","published-print":{"date-parts":[[2009,2,17]]}},"alternative-id":["10.1073\/pnas.0808075106"],"URL":"https:\/\/doi.org\/10.1073\/pnas.0808075106","relation":{},"ISSN":["0027-8424","1091-6490"],"issn-type":[{"value":"0027-8424","type":"print"},{"value":"1091-6490","type":"electronic"}],"subject":[],"published":{"date-parts":[[2009,2,17]]},"assertion":[{"value":"2008-08-14","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2009-02-17","order":2,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}