title: Stability of the volume of air trapped on the abdomen of the water spider Argyroneta aquatica.
abstract: The water spider Argyroneta aquatica lives under water, diving to various depths from time to time. At rest, it breathes air trapped within its diving bell with a hydrophilic surface. Outside their diving bell water spiders trap air on their abdomen under a layer of hydrophobic hair. Is the structure of the layer of hair trapping a volume of air on the abdomen of the water spider Argyroneta aquatica under water related to its observed diving depth (of the order of decimetre)? A positive answer to this question is given, based on the law of Laplace in combination with information obtained from SEM- photographs of the abdomen of a water spider.
authors.affiliation: Cologne Biocentre, University of Cologne, Köln, Germany.
authors.forename: Dietrich
authors.initials: D
authors.lastname: Neumann
authors.affiliation: Institute of Physical Chemistry, University of Cologne, Köln, Germany.
authors.forename: Dietrich
authors.initials: D
authors.lastname: Woermann
keywords: Argyroneta aquatica; Physical stability; Plastron