title: The influence of humidity on the attachment ability of the spider Philodromus dispar (Araneae, Philodromidae).
abstract: Hairy attachment devices that are not supplemented with fluid secretion have evolved independently in lizards and spiders. van der Waals forces have previously been shown to be responsible for excellent adhesive properties of these structures, but it has recently been reported that wetting phenomena also play an important role in such 'dry adhesives'. To investigate the effect of ambient humidity on the attachment of the living spider Philodromus dispar, traction force was measured on a smooth epoxy resin surface at relative humidities (RHs) of 15, 50, 70, 80 and 99 per cent. The results show that attachment ability is significantly higher at an intermediate humidity compared with that in a dry atmosphere and at high humidity. Water condensation on the substrate surface almost completely abolishes adhesion. Experimental results obtained may be explained by an increase in capillarity or changes in mechanical properties of setae and spatulae owing to water absorption by the cuticle at an intermediate RH. The results obtained show dry adhesion limits under different environmental conditions and are important for understanding spider biology.
authors: Functional Morphology and Biomechanics, Christian Albrechts University of Kiel, Am Botanischen Garten 1-9, 24098 Kiel, Germany.
authors: Jonas O
authors: JO
authors: Wolff
authors: Stanislav N
authors: SN
authors: Gorb
references: J Chem Phys. 2004 Jan 15;120(3):1157-60
references: 15268236
references: PLoS One. 2008 May 14;3(5):e2192
references: 18478106
references: Microsc Res Tech. 1999 Mar 1;44(5):327-38
references: 10090207
references: Proc Natl Acad Sci U S A. 2005 Nov 8;102(45):16293-6
references: 16260737
references: J Exp Biol. 2003 Nov;206(Pt 22):3905-11
references: 14555732
references: Integr Comp Biol. 2002 Dec;42(6):1127-39
references: 21680397
references: J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2006 Nov;192(11):1223-32
references: 16865371
references: J Chem Phys. 2006 May 7;124(17):174712
references: 16689595
references: Z Zellforsch Mikrosk Anat. 1970;104(1):87-106
references: 5414492
references: Arthropod Struct Dev. 2004 Jul;33(3):187-99
references: 18089034
references: Z Zellforsch Mikrosk Anat. 1969;97(1):137-59
references: 4895249
references: Adv Colloid Interface Sci. 2002 Feb 25;96(1-3):213-30
references: 11908788
references: Proc Natl Acad Sci U S A. 2002 Sep 17;99(19):12252-6
references: 12198184
references: J R Soc Interface. 2006 Jun 22;3(8):441-51
references: 16849272
references: J Exp Biol. 2010 Nov 1;213(Pt 21):3699-704
references: 20952618
references: J Morphol. 1965 Nov;117(3):271-93
references: 5883924
references: Proc Natl Acad Sci U S A. 2003 Sep 16;100(19):10603-6
references: 12960386