81urn:lsid:arphahub.com:pub:EE60897E-EDEE-5EC8-86EB-7203BECD195DARPHA Conference AbstractsACA2603-3925Pensoft Publishers10.3897/aca.5.e829418294119105Conference AbstractProceedings of the 25th International Conference on Subterranean Biology (Cluj-Napoca, 18-22 July 2022)Quantifying troglomorphism in hyperspaceMammolaStefanostefano.mammola@cnr.ithttps://orcid.org/0000-0002-4471-905512PavlekMartinahttps://orcid.org/0000-0001-6710-0581345ArnedoMiquel A.https://orcid.org/0000-0003-1402-47275MilanoFilippo6MilioneRoberto62TolveMarcohttps://orcid.org/0000-0002-3013-73376IsaiaMarcohttps://orcid.org/0000-0001-5434-21276CardosoPedrohttps://orcid.org/0000-0001-8119-99601Laboratory for Integrative Biodiversity Research (LIBRe), Finnish Museum of Natural History (LUOMUS), University of Helsinki, Helsinki, FinlandLaboratory for Integrative Biodiversity Research (LIBRe), Finnish Museum of Natural History (LUOMUS), University of HelsinkiHelsinkiFinlandMolecular Ecology Group (dark-MEG), Water Research Institute (IRSA), National Research Council (CNR), Verbania Pallanza, ItalyMolecular Ecology Group (dark-MEG), Water Research Institute (IRSA), National Research Council (CNR)Verbania PallanzaItalyRuđer Bošković Institute, Zagreb, CroatiaRuđer Bošković InstituteZagrebCroatiaCroatian Biospeleological Society, Zagreb, CroatiaCroatian Biospeleological SocietyZagrebCroatiaUniversity of Barcelona, Barcelona, SpainUniversity of BarcelonaBarcelonaSpainDepartment of Life Sciences and Systems Biology, University of Torino, Torino, ItalyDepartment of Life Sciences and Systems Biology, University of TorinoTorinoItaly
2022140420225e82941A37C7192-52E4-5955-9055-8768DDECF81EStefano Mammola, Martina Pavlek, Miquel A. Arnedo, Filippo Milano, Roberto Milione, Marco Tolve, Marco Isaia, Pedro CardosoThis is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Many ecological and evolutionary studies require to quantify the degree of adaptation of subterranean species to caves or other subterranean systems. In 1962, Kenneth A. Christiansen (1924–2017) coined the term “troglomorphism” to illustrate the process of subterranean adaptation and the suite of adaptive traits of organisms (“troglomorphic traits” or “troglomorphies”) (Christiansen 1962). Although this term was proposed in a paper published in French, “troglomorphism” and its derivatives (e.g. “troglobiomorphism”) became widely adopted jargon in subterranean biology. Yet, after decades of work and countless discussions around the subtle meanings of the term, there is still no consensus on how to best quantify troglomorphism in a simple operational way to support eco-evolutionary research. In a recent interview, Boris Sket made the excellent point that “nothing [makes] sense in speleobiology without a comparison of cave animals with the 'normal' epigean ones” (Lučić 2021). Building on this idea, we contend that one could quantify troglomorphism on a continuous scale within a given group of organisms (e.g., family or genus) as the functional distance of each species to the phylogenetically closest surface species or the “average” surface species (depending on whether phylogenetic information is available or not). We illustrate this approach using subterranean spiders in the genus Troglohyphantes, a well-studied group for which both a phylogeny and functional traits are available (Isaia et al. 2017, Mammola et al. 2020). We tested two approaches: i) quantifying adaptation as the morphological distance of each species to the phylogenetically closest surface-dwelling relative; ii) using a kernel density n-dimensional hypervolume (sensuBlonder et al. 2014) to construct the morphospace occupied by all surface-dwelling species of Troglohyphantes, and quantifying the degree of adaptation of subterranean species as their distance from the centroid of this “average” surface species. To test the effectiveness of these alternative methods, we compare how functional distance varies in relation the habitat occupied by each species (deep caves vs cave entrances vs interstitial habitats) and its range size. We suggest our approach could be applied to any group of subterranean organisms for which a surface relative is known, allowing to explore a range of questions on the degree to which the specialization of a given community relates to local environmental conditions, interspecific interactions, and more.
Horizon 2020 Marie Sklodowska-Curie Individual Fellowships program (H2020-MSCA-IF-2019).
Hosting institution
Finnish Museum of Natural History – University of Helsinki
Conflicts of interest
None declared.
Funding program
Horizon 2020 Marie Sklodowska-Curie Individual Fellowships program (H2020-MSCA-IF-2019).
Grant title
Project CAWEB "Testing macroecological theory using simplified systems" (project number 882221)
Hosting institution
Finnish Museum of Natural History – University of Helsinki
Conflicts of interest
None declared.
Author contributions
S.M. and P.C. conceived the study and designed the methodology. S.M. conducted analyses. F.M. and R.M. collected distribution data. M.I. and M.T. collected functional traits. M.A.A. and M.P. analysed phylogenetic data.
ReferencesBlonderBenjaminLamannaChristineViolleCyrilleEnquistBrian J.2014Then-dimensional hypervolume23559560910.1111/geb.12146ChristiansenK. A.1962Proposition pour la classification des animaux cavernicoles.27578IsaiaMarcoMammolaStefanoMazzucaPaolaArnedoMiquel A.PantiniPaolo2017Advances in the systematics of the spider genus Troglohyphantes (Araneae, Linyphiidae)15430732610.1080/14772000.2016.1254304LučićIvo2021Nothing has a sense in speleobiology, without a comparison of cave animals with the 'normal' epigean ones5015910.3986/ac.v50i1.10102MammolaStefanoArnedoMiquel A.FišerCeneCardosoPedroDejanazAndrea J.IsaiaMarco2020Environmental filtering and convergent evolution determine the ecological specialization of subterranean spiders3451064107710.1111/1365-2435.13527