J.Comparat.Physiol.A 195(9), 881-894, 2009
B. Hößl¹², H.J. Böhm¹,
C.F. Schaber², F.G. Rammerstorfer¹,
¹Institute of Lightweight Design and Structural
TU Wien, Vienna, Austria
²Department of Neurobiology and Cognition Research,
Faculty of Sciences,
University of Vienna, Vienna, Austria
Arachnid slit sensilla respond to minute strains in the exoskeleton.
After having applied Finite Element (FE) analysis to simpliWed arrays of five
straight slits (Höß et al. J Comp Physiol A 193:445–459, 2007) we
now present a computational study of the eVects of more subtle natural
variations in geometry, number and arrangement of slits on the slit face
Our simulations show that even minor variations in these parameters can
substantially influence a slit’s directional response.
Using white-light interferometric measurements of the surface deformations of a
lyriform organ, it is shown that planar FE models are capable of predicting the
principal characteristics of the mechanical responses.
The magnitudes of the measured and calculated slit face deformations are in
At threshold, they measure between 1.7 and 43 nm.
In a lyriform organ and a closely positioned loose group of slits, the
detectable range of loads increases to approximately 3.5 times the range of the
lyriform organ alone.
Stress concentration factors (up to ca. 29) found in the vicinity of the slits
were evaluated from the models.
They are mitigated due to local thickening of the exocuticle and the
arrangement of the chitinous microWbers that prevents the formation of
cracks under physiological loading conditions.