122
Joseph A. C. Humphrey et al.
structure are expected to involve very small changes in mass and, therefore, might
be less costly relative to the mass changes required to alter hair length or diameter.
A model describing hair motion can be coupled to an optimization procedure,
such as a genetic algorithm, to calculate possible evolution scenarios resulting in
optimally performing hairs: meaning optimal values of d, L, R, and S for a
particular stimulus frequency or sensitivity in a fluid medium. However, what is
"optimal" has to be decided (and may be a moving target) and an associated "cost
function" must be defined. In addition, to obtain realistic results, biological,
physical-chemical, mechanical, and ecological constraints must be imposed on
such an optimization problem. This is the subject of continuing research by the
authors.
Acknowledgments. The authors acknowledge helpful discussions with Aaron
Spak and thank him for his assistance in preparing the figures. FGB was supported
by a grant from the Austrian Science Foundation (FWF P 12 192 BIO) and JACH
by a grant from the National Science Foundation (9907203).
References
Barth FG (2000) How to catch the wind: spider hairs specialized for sensing the
movement of air. Narturwissenschaften 87:51-58
Barth FG, Humphrey JAC, Wast! U, Halbritter J, Brittinger W (1995) Dynamics
of arthropod filiform hairs. III. Flow patterns related to air movement detection
in a spider (Cupiennius salei Keys.). Phil Trans R Soc London, B 347:397412
Barth FG, Wast) U, Humphrey JAC, Devarakonda R (1993) Dynamics of
arthropod filiform hairs. II. Mechanical properties of spider trichobothria
(Cupiennius salei Keys.). Phil Trans R Soc London, B 340:445-461
Bleckmann H (1994) Reception of Hydrodynamic Stimuli in Aquatic and
Semiaquatic Animals. Stuttgart, Jena, New York: G. Fischer
Devarakonda R, Barth FG, Humphrey JAC (1996) Dynamics of arthropod filiform
hairs. IV. Hair motion in air and water. Phil Trans R Soc London, B
351:933-946
Fletcher NH (1978) Acoustical response of hair receptors in insects. J Comp
Physiol127:185-189
Humphrey JAC, Devarakonda R, Iglesias I, Barth FG (1993) Dynamics of
arthropod filiform hairs. I. Mathematical modelling of the hair and air motions.
Phil Trans R Soc London, B 340:423-444
Humphrey JAC, Devarakonda R, Iglesias I, Barth FG (1997) Errata for Dynamics
of arthropod filiform hairs. I. Mathematical modelling of the hair and air
motions. Phil Trans R Soc London, B 352:1995
Kumagai T, Shimozawa T, Baba Y (1998) Mobilities of the cereal wind-receptor
hairs of the cricket, Gryllus bimaculatus. J Comp Physiol 183:7-21
Joseph A. C. Humphrey et al.
structure are expected to involve very small changes in mass and, therefore, might
be less costly relative to the mass changes required to alter hair length or diameter.
A model describing hair motion can be coupled to an optimization procedure,
such as a genetic algorithm, to calculate possible evolution scenarios resulting in
optimally performing hairs: meaning optimal values of d, L, R, and S for a
particular stimulus frequency or sensitivity in a fluid medium. However, what is
"optimal" has to be decided (and may be a moving target) and an associated "cost
function" must be defined. In addition, to obtain realistic results, biological,
physical-chemical, mechanical, and ecological constraints must be imposed on
such an optimization problem. This is the subject of continuing research by the
authors.
Acknowledgments. The authors acknowledge helpful discussions with Aaron
Spak and thank him for his assistance in preparing the figures. FGB was supported
by a grant from the Austrian Science Foundation (FWF P 12 192 BIO) and JACH
by a grant from the National Science Foundation (9907203).
References
Barth FG (2000) How to catch the wind: spider hairs specialized for sensing the
movement of air. Narturwissenschaften 87:51-58
Barth FG, Humphrey JAC, Wast! U, Halbritter J, Brittinger W (1995) Dynamics
of arthropod filiform hairs. III. Flow patterns related to air movement detection
in a spider (Cupiennius salei Keys.). Phil Trans R Soc London, B 347:397412
Barth FG, Wast) U, Humphrey JAC, Devarakonda R (1993) Dynamics of
arthropod filiform hairs. II. Mechanical properties of spider trichobothria
(Cupiennius salei Keys.). Phil Trans R Soc London, B 340:445-461
Bleckmann H (1994) Reception of Hydrodynamic Stimuli in Aquatic and
Semiaquatic Animals. Stuttgart, Jena, New York: G. Fischer
Devarakonda R, Barth FG, Humphrey JAC (1996) Dynamics of arthropod filiform
hairs. IV. Hair motion in air and water. Phil Trans R Soc London, B
351:933-946
Fletcher NH (1978) Acoustical response of hair receptors in insects. J Comp
Physiol127:185-189
Humphrey JAC, Devarakonda R, Iglesias I, Barth FG (1993) Dynamics of
arthropod filiform hairs. I. Mathematical modelling of the hair and air motions.
Phil Trans R Soc London, B 340:423-444
Humphrey JAC, Devarakonda R, Iglesias I, Barth FG (1997) Errata for Dynamics
of arthropod filiform hairs. I. Mathematical modelling of the hair and air
motions. Phil Trans R Soc London, B 352:1995
Kumagai T, Shimozawa T, Baba Y (1998) Mobilities of the cereal wind-receptor
hairs of the cricket, Gryllus bimaculatus. J Comp Physiol 183:7-21