Interaction between arthropod filiform hairs in a fluid environment

Abstract

Many arthropods use filiform hairs as mechanoreceptors to detect air motion. In common house crickets (Acheta domestica) the hairs cover two antenna-like appendages called cerci at the rear of the abdomen. The biomechanical stimulus-response properties of individual filiform hairs have been investigated and modeled extensively in several earlier studies. However, only a few previous studies have considered viscosity-mediated coupling between pairs of hairs, and only in particular configurations. Here we present a model capable of calculating hair-to-hair coupling in arbitrary configurations. We simulate the coupled motion of a small group of mechanosensory hairs on a cylindrical section of cercus. We have found that the coupling effects are non-negligible, and likely constrain the operational characteristics of the cercal sensory array.

Why do insects have such a high density of flow-sensing hairs? Insights from the hydromechanics of biomimetic MEMS sensors

“…This was also recently observed in another computational study by Heys et al (2008). Furthermore, Cummins et al (2007) computed interactions for a group of several hairs and predicted (i) large phase shifts between hairs and (ii) the presence of 'dead zones' within the hair canopy, caused by strong coupling between hairs. More recently, Lewin & Hallam (in press) showed, again using computational fluid dynamics models, that viscous coupling can be negative when hairs are arranged perpendicular to the flow, implying an increased sensitivity of a hair owing to the inhibitory effects of its neighbour (see also Cheer & Koehl (1987), for an earlier study on variable interactions depending on the flow direction relative to hair arrangement).…”

“…Hair diameter has a substantial effect on the extent of viscous coupling (figure 6), whereas the effect on flow caused by thin hairs is smaller in absolute terms, it is larger when flow perturbation is considered relative to hair diameter. Given the above caveats, our limited understanding of the effect of transverse flow on hydrodynamic interactions (Lewin & Hallam in press) and even poorer understanding for groups of hairs (Cummins et al 2007), we are far from a thorough intuitive grasp of hydrodynamic interactions within hair canopies.…”

“…Recently, Cummins et al (2007) applied computational methods to the same problem. Their results largely confirmed those of Bathellier et al (2005) with two exceptions.…”

Bat wing sensors support flight control

“…For the recording after depilation, the effective diameter of the air puffs is irrelevant, because the entire wing surface was depilated. Also, because of the great distance between individual hairs with on average one hair per mm 2 with a hair diameter at the base of 5-6 μm and the known length range, nonlinear coupling between the hairs can be excluded if the distance is greater than 50 hair diameters (30,31), which would be in our case around 275 μm.…”

Recent advances in biomimetic sensing technologies

“…Analysis of the canopy response of the cercal mechanosensor array, however, is less comprehensive. Modelling of a hairbased mechanosensor array has revealed viscous-mediated coupling effects to be non-negligible in crickets (Cummins et al 2007) and spiders (Barthellier et al 2005). This implies that, although the study of single hair mechanics is warranted in its own right, it cannot tell us the whole story.…”