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Heiss E, Handschuh S, Aerts P, Van Wassenbergh S. A tongue for all seasons: extreme phenotypic flexibility in salamandrid newts. Sci Rep 2017; 7:1006. [PMID: 28432290 PMCID: PMC5430857 DOI: 10.1038/s41598-017-00674-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 03/08/2017] [Indexed: 01/23/2023] Open
Abstract
Many organisms faced with seasonally fluctuating abiotic and biotic conditions respond by altering their phenotype to account for the demands of environmental changes. Here we discovered that newts, which switch seasonally between an aquatic and terrestrial lifestyle, grow a complex adhesive system on their tongue pad consisting of slender lingual papillae and mucus-producing cells to increase the efficiency of prey capture as they move from water onto land. The adhesive system is reduced again as newts switch back to their aquatic stage, where they use suction to capture prey. As suction performance is also enhanced seasonally by reshaping of the mouth due to the growth of labial lobes, our results show that newts are exceptional in exhibiting phenotypic flexibility in two alternating components (i.e. tongue pad and labial lobes) within a single functional system, and suggest that this form of phenotypic flexibility demands complex genetic regulation.
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Affiliation(s)
- Egon Heiss
- Institute of Systematic Zoology and Evolutionary Biology, Friedrich-Schiller-University Jena, Erbertstr. 1, 07743, Jena, Germany.
| | - Stephan Handschuh
- VetCore Facility for Research, Imaging Unit, University for Veterinary Medicine Vienna, Veterinärplatz 1, 1210, Vienna, Austria
| | - Peter Aerts
- Department of Biology, University of Antwerp, Universiteitsplein 1, B-2610, Antwerp, Belgium.,Department of Movement and Sports Sciences, Ghent University, Watersportlaan 2, B-9000, Ghent, Belgium
| | - Sam Van Wassenbergh
- Department of Biology, University of Antwerp, Universiteitsplein 1, B-2610, Antwerp, Belgium.,Departement d'Ecologie et de Gestion de la Biodiversité, Muséum National d' Histoire Naturelle, 57 rue Cuvier, Case postale 55, 75231, Paris Cedex 5, France
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Van Wassenbergh S, Heiss E. Phenotypic flexibility of gape anatomy fine-tunes the aquatic prey-capture system of newts. Sci Rep 2016; 6:29277. [PMID: 27383663 PMCID: PMC4935879 DOI: 10.1038/srep29277] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 06/16/2016] [Indexed: 12/05/2022] Open
Abstract
A unique example of phenotypic flexibility of the oral apparatus is present in newts (Salamandridae) that seasonally change between an aquatic and a terrestrial habitat. Newts grow flaps of skin between their upper and lower jaws, the labial lobes, to partly close the corners of the mouth when they adopt an aquatic lifestyle during their breeding season. Using hydrodynamic simulations based on μCT-scans and cranial kinematics during prey-capture in the smooth newt (Lissotriton vulgaris), we showed that this phenotypic flexibility is an adaptive solution to improve aquatic feeding performance: both suction distance and suction force increase by approximately 15% due to the labial lobes. As the subsequent freeing of the corners of the mouth by resorption of the labial lobes is assumed beneficial for the terrestrial capture of prey by the tongue, this flexibility of the mouth fine-tunes the process of capturing prey throughout the seasonal switching between water and land.
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Affiliation(s)
- Sam Van Wassenbergh
- Department of Biology, Universiteit Antwerpen, Universiteitsplein 1, B-2610 Antwerpen, Belgium
- Evolutionary Morphology of Vertebrates, Ghent University, K.L. Ledeganckstraat 35, B-9000 Gent, Belgium
- Departement d’Ecologie et de Gestion de la Biodiversité, Muséum National d’ Histoire Naturelle, 57 rue Cuvier, Case postale 55, 75231, Paris Cedex 5, France
| | - Egon Heiss
- Institute of Systematic Zoology and Evolutionary Biology, Friedrich-Schiller-University Jena, Erbertstraße 1, 07743 Jena, Germany
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Heiss E, Handschuh S, Aerts P, Van Wassenbergh S. Musculoskeletal architecture of the prey capture apparatus in salamandrid newts with multiphasic lifestyle: does anatomy change during the seasonal habitat switches? J Anat 2016; 228:757-70. [PMID: 26892189 DOI: 10.1111/joa.12445] [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] [Accepted: 12/29/2015] [Indexed: 11/30/2022] Open
Abstract
Some newt species change seasonally between an aquatic and a terrestrial life as adults, and are therefore repeatedly faced with different physical circumstances that affect a wide range of functions of the organism. For example, it has been observed that seasonally habitat-changing newts display notable changes in skin texture and tail fin anatomy, allowing one to distinguish an aquatic and a terrestrial morphotype. One of the main functional challenges is the switch between efficient aquatic and terrestrial prey capture modes. Recent studies have shown that newts adapt quickly by showing a high degree of behavioral flexibility, using suction feeding in their aquatic stage and tongue prehension in their terrestrial stage. As suction feeding and tongue prehension place different functional demands on the prey capture apparatus, this behavioral flexibility may clearly benefit from an associated morphological plasticity. In this study, we provide a detailed morphological analysis of the musculoskeletal system of the prey capture apparatus in the two multiphasic newt species Ichthyosaura alpestris and Lissotriton vulgaris by using histological sections and micro-computed tomography. We then test for quantitative changes of the hyobranchial musculoskeletal system between aquatic and terrestrial morphotypes, The descriptive morphology of the cranio-cervical musculoskeletal system provides new insights on form and function of the prey capture apparatus in newts, and the quantitative approach shows hypertrophy of the hyolingual musculoskeletal system in the terrestrial morphotype of L. vulgaris but hypertrophy in the aquatic morphotype of I. alpestris. It was therefore concluded that the seasonal habitat shifts are accompanied by a species-dependent muscular plasticity of which the potential effect on multiphasic feeding performance in newts remains unclear.
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Affiliation(s)
- Egon Heiss
- Institute of Systematic Zoology and Evolutionary Biology, Friedrich-Schiller-University Jena, Jena, Germany
| | - Stephan Handschuh
- VetCore Facility for Research, Imaging Unit, University for Veterinary Medicine Vienna, Vienna, Austria
| | - Peter Aerts
- Department of Biology, University of Antwerp, Antwerp, Belgium.,Department of Movement and Sports Sciences, Ghent University, Ghent, Belgium
| | - Sam Van Wassenbergh
- Department of Biology, University of Antwerp, Antwerp, Belgium.,Evolutionary Morphology of Vertebrates, Ghent University, Ghent, Belgium
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Flexibility is everything: prey capture throughout the seasonal habitat switches in the smooth newt Lissotriton vulgaris. ORG DIVERS EVOL 2014; 15:127-142. [PMID: 26097413 PMCID: PMC4470538 DOI: 10.1007/s13127-014-0187-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 10/16/2014] [Indexed: 11/08/2022]
Abstract
Transitions between aquatic and terrestrial habitats are significant steps in vertebrate evolution. Due to the different biophysical demands on the whole organism in water and air, such transitions require major changes of many physiological functions, including feeding. Accordingly, the capability to modulate the pre-programmed chain of prey-capture movements might be essential to maintain performance in a new environment. Newts are of special interest in this regard as they show a multiphasic lifestyle where adults change seasonally between an aquatic and a terrestrial stage. For instance, the Alpine newt is capable of using tongue prehension to feed on land only when in the terrestrial stage, but still manages to suction feed if immersed whilst in terrestrial stage. During the aquatic stage, terrestrial feeding always involved grasping prey by the jaws. Here, we show that this seasonal shift in feeding behavior is also present in a species with a shorter terrestrial stage, the smooth newt Lissotriton vulgaris. Behavioral variability increases when animals change from aquatic to terrestrial strikes in the aquatic stage, but prey-capture movements seem to be generally well-coordinated across the feeding modes. Only suction feeding in the terrestrial stage was seldom performed and appeared uncoordinated. Our results indicate that newts exhibit a high degree of seasonal flexibility of the prey-capture behavior. The similarity between movement patterns of suction feeding and terrestrial feeding suggests that only relatively subtle neuromotoric adjustments to the ancestral, suction-feeding motor program are required to successfully feed in the new environment.
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Heiss E, Aerts P, Van Wassenbergh S. Masters of change: seasonal plasticity in the prey-capture behavior of the Alpine newt Ichthyosaura alpestris (Salamandridae). ACTA ACUST UNITED AC 2014; 216:4426-34. [PMID: 24259258 DOI: 10.1242/jeb.091991] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Transitions between aquatic and terrestrial environments are significant steps in vertebrate evolution. These transitions require major changes in many biological functions, including food uptake and transport. The Alpine newt, Ichthyosaura alpestris, is known to show a 'multiphasic lifestyle' where the adult shifts from a terrestrial to an aquatic lifestyle and then back to a terrestrial lifestyle every year as a result of its breeding activity. These transitions correspond to dramatic changes in morphology, physiology and behavior, resulting in distinct aquatic and terrestrial morphotypes. We hypothesized that these shifts go along with changes in prey-capture mechanics to maintain a sufficiently high performance in both environments. We analyzed the prey-capture kinematics in the four possible modes: aquatic strikes in the aquatic phase, terrestrial strikes in the terrestrial phase, aquatic strikes in the terrestrial phase and terrestrial strikes in the aquatic phase. A multivariate comparison detected significant kinematic differences between the phase-specific feeding modes. In both the aquatic and the terrestrial phase, I. alpestris uses a suction-feeding mechanism for capturing prey in water. By contrast, I. alpestris uses a jaw-based grasping mechanism with a kinematic profile similar to the aquatic modes for terrestrial prey-capture in its aquatic phase but an elaborate lingual-based prehension mechanism to capture terrestrial prey in the terrestrial phase. These results exhibit a so-far unknown amount of behavioral plasticity in prey-capture behavior that is tuned to the seasonal demands of performance, and exemplify functional mechanisms behind aquatic-terrestrial transitions in vertebrates.
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Affiliation(s)
- Egon Heiss
- Department of Biology, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp, Belgium
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Perrotta I, Sperone E, Bernabò I, Tripepi S, Brunelli E. The shift from aquatic to terrestrial phenotype in Lissotriton italicus: larval and adult remodelling of the skin. ZOOLOGY 2012; 115:170-8. [DOI: 10.1016/j.zool.2011.10.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2011] [Revised: 09/14/2011] [Accepted: 10/13/2011] [Indexed: 10/28/2022]
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The morphology of the dorsal and ventral skin of Triturus karelinii (Caudata: Salamandridae). Biologia (Bratisl) 2011. [DOI: 10.2478/s11756-011-0009-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Brunelli E, Sperone E, Maisano M, Tripepi S. Morphology and ultrastructure of the gills in two Urodela species:Salamandrina terdigitataandTriturus carnifex. ACTA ACUST UNITED AC 2009. [DOI: 10.1080/11250000802484869] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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de Brito-Gitirana L, Azevedo RA. Morphology of Bufo ictericus integument (Amphibia, Bufonidae). Micron 2005; 36:532-8. [PMID: 15975802 DOI: 10.1016/j.micron.2005.03.013] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2004] [Revised: 03/16/2005] [Accepted: 03/28/2005] [Indexed: 11/28/2022]
Abstract
Bufo ictericus integument was investigated by stereoscopic, low vacuum scanning electron microscopy, transmission electron microscopy and light microscopy. The studies revealed, that the dorsal integument surface is rougher than ventral. Three types of projections are visualized: larger rounded verrucae, smaller conical cornified tubercles, and conical short spines. Prominent verrucae are observed on the dorsal surface, being flatter on the ventral surface. The tubercles are visualized only on the dorsal surface. The verrucae are separated by grooves that may contribute spreading and retention of the glandular secretion upon the integument. The pattern of the epidermal grooves is also important for water distribution, protecting the animal against desiccation. The epidermis is composed of a stratified epithelium with intraepithelial blood vessels, where keratinocytes predominate, but flask cells, and Merkel cells also occur. In the spongious dermis, cutaneous glands are visualized. The compact dermis is a series of alternating layers of bundles of collagenous fibers, and between spongious and compact dermis there are basophilic areas that correspond to Eberth-Katschenko layer. The dorsal and the ventral surfaces of B. ictericus are morphologically distinct. The integument structure is related to the physiology of each surface and represents an adaptation to habitat, reflecting a lifestyle of the animal.
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Affiliation(s)
- L de Brito-Gitirana
- Laboratory of Animal and Comparative Histology, Department of Histology and Embryology, Federal University of Rio de Janeiro, Cidade Universitária, Ilha do Fundão, Brazil
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