title: How do the substrate reaction forces acting on a gecko's limbs respond to inclines?
abstract: Locomotion is an essential character of animals, and excellent moving ability results from the delicate sensing of the substrate reaction forces (SRF) acting on body and modulating the behavior to adapt the motion requirement. The inclined substrates present in habitats pose a number of functional challenges to locomotion. In order to effectively overcome these challenges, climbing geckos execute complex and accurate movements that involve both the front and hind limbs. Few studies have examined gecko's SRF on steeper inclines of greater than 90°. To reveal how the SRFs acting on the front and hind limbs respond to angle incline changes, we obtained detailed measurements of the three-dimensional SRFs acting on the individual limbs of the tokay gecko while it climbed on an inclined angle of 0-180°. The fore-aft forces acting on the front and hind limbs show opposite trends on inverted inclines of greater than 120°, indicating propulsion mechanism changes in response to inclines. When the incline angles change, the forces exerted in the normal and fore-aft directions by gecko's front and hind limbs are reassigned to take full advantage of limbs' different roles in overcoming resistance and in propelling locomotion. This also ensures that weight acts in the angle range between the forces generated by the front and hind limbs. The change in the distribution of SRF with a change in the incline angle is directly linked to the favorable trade-off between locomotive maneuverability and stability.
authors: Institute of Bio-inspired Structure and Surface Engineering, Nanjing University of Aeronautics and Astronautics, 29 Yudao Street, Nanjing, Jiangsu, 210016, China.
authors: Zhouyi
authors: Z
authors: Wang
authors: Zhendong
authors: Z
authors: Dai
authors: Wei
authors: W
authors: Li
authors: Aihong
authors: A
authors: Ji
authors: Wenbao
authors: W
authors: Wang
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena / Q000502:physiology*; D017753:Ecosystem; D005121:Extremities / Q000502:physiology*; D008116:Lizards / Q000502:physiology*; D009043:Motor Activity / Q000502:physiology*
references: Proc Natl Acad Sci U S A. 2010 Apr 13;107(15):7078-82
references: 20351297
references: J Biomech. 2008 Aug 7;41(11):2388-95
references: 18619599
references: Zoology (Jena). 2007;110(2):93-103
references: 17374478
references: J Exp Biol. 2006 Jan;209(Pt 2):260-72
references: 16391348
references: J R Soc Interface. 2009 Jun 6;6(35):529-37
references: 18801716
references: J Biomech. 2009 Feb 9;42(3):336-40
references: 19136114
references: Am J Physiol. 1977 Nov;233(5):R243-61
references: 411381
references: J Exp Biol. 2011 Aug 1;214(Pt 15):2544-59
references: 21753049
references: J Exp Biol. 2006 Aug;209(Pt 15):2990-3000
references: 16857883
references: J Exp Biol. 2001 Apr;204(Pt 7):1233-46
references: 11249834
references: J Exp Biol. 2006 Sep;209(Pt 18):3569-79
references: 16943497
references: J Exp Biol. 2010 Nov 1;213(Pt 21):3615-24
references: 20952609
references: J R Soc Interface. 2006 Oct 22;3(10):689-97
references: 16971337
references: J R Soc Interface. 2013 Jan 16;10(80):20120838
references: 23325755
references: J Exp Biol. 2012 Jul 1;215(Pt 13):2288-300
references: 22675190
references: Proc Natl Acad Sci U S A. 2006 Dec 19;103(51):19320-5
references: 17148600
references: J R Soc Interface. 2008 Mar 6;5(20):339-48
references: 17567553
references: J Exp Biol. 2004 Sep;207(Pt 20):3507-14
references: 15339946
references: J Exp Biol. 2004 Jan;207(Pt 3):553-63
references: 14691103
references: J Exp Biol. 2002 Aug;205(Pt 16):2479-88
references: 12124371
references: Bioinspir Biomim. 2015 Feb 04;10(1):016019
references: 25650374
references: J Exp Biol. 1999 Dec;202(Pt 24):3565-73
references: 10574733
references: J Exp Biol. 2011 Mar 1;214(Pt 5):703-8
references: 21307055
references: J Exp Biol. 2006 Jan;209(Pt 2):249-59
references: 16391347
references: J R Soc Interface. 2007 Dec 22;4(17):1071-6
references: 17374591
references: Science. 2000 Apr 7;288(5463):100-6
references: 10753108
references: J Exp Biol. 2004 Apr;207(Pt 10):1715-28
references: 15073204
references: J Exp Biol. 2013 Apr 15;216(Pt 8):1448-57
references: 23264492
references: J R Soc Interface. 2006 Jun 22;3(8):441-51
references: 16849272
references: Nature. 2000 Jun 8;405(6787):681-5
references: 10864324
references: J Exp Biol. 2014 Jan 15;217(Pt 2):283-9
references: 24115057
references: Proc Natl Acad Sci U S A. 2005 Nov 8;102(45):16293-6
references: 16260737
references: Bioinspir Biomim. 2011 Dec;6(4):046005
references: 21993149
references: J Exp Biol. 2006 Oct;209(Pt 20):4154-66
references: 17023608
references: J Exp Biol. 2011 Feb 1;214(Pt 3):402-11
references: 21228199