title: Ultrastructure and mineral distribution in the tergal cuticle of the terrestrial isopod Titanethes albus. Adaptations to a karst cave biotope.
abstract: Composition and spatial distribution of organic and inorganic materials within the cuticle of isopods vary between species. These variations are related to the behaviour and habitat of the animal. The troglobiotic isopod Titanethes albus lives in the complete darkness of caves in the Slovenian Karst. This habitat provides constant temperature and saturated humidity throughout the year and inconsistent food supply. These conditions should have lead to functional adaptations of arthropod cuticles. However, studies on structure and composition of cave arthropod cuticles are rare and lacking for terrestrial isopods. We therefore analysed the tergite cuticle of T. albus using transmission and field-emission electron microscopy, confocal micro-Raman spectroscopic imaging, quantitative X-ray diffractometry, thermogravimetric analysis and atomic absorption spectroscopy. The ultrastructure of the epicuticle suggests a poor resistance against water loss. A weak interconnection between the organic and mineral phase within the endo- and exocuticle, a comparatively thin apical calcite layer, and almost lack of magnesium within the calcite crystal lattice suggest that the mechanical strength of the cuticle is low in the cave isopod. This may possibly be of advantage in maintaining high cuticle flexibility and reducing metabolic expenditures.
authors.affiliation: Central Facility for Electron Microscopy, University of Ulm, Ulm, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Hild
authors.forename: Frank
authors.initials: F
authors.lastname: Neues
authors.forename: Nada
authors.initials: N
authors.lastname: Znidarsic
authors.forename: Jasna
authors.initials: J
authors.lastname: Strus
authors.forename: Matthias
authors.initials: M
authors.lastname: Epple
authors.forename: Othmar
authors.initials: O
authors.lastname: Marti
authors.forename: Andreas
authors.initials: A
authors.lastname: Ziegler
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D002119:Calcium Carbonate / Q000378:metabolism; D033321:Isopoda / Q000378:metabolism* / Q000648:ultrastructure*; D008274:Magnesium / Q000378:metabolism; D046529:Microscopy, Electron, Transmission; D008903:Minerals / Q000378:metabolism*; D013059:Spectrum Analysis, Raman; D014867:Water / Q000737:chemistry
chemical_list: D008903:Minerals; D014867:Water; D002119:Calcium Carbonate; D008274:Magnesium; D002118:Calcium