Optimization Of Bio-inspired Hair Sensor Arrays

Crickets use a pair of hairy appendages on their abdomen called cerci, each of which contains numerous mechano-receptive filiform hairs. These sensitive hairs can respond even to the slightest air movements, down to 0.03 mm/s, generated by the approaching predators and initiating an escape mechanism in the crickets. Bio-mimicking the cricket cerci, arrays of artificial hair sensors have been successfully fabricated using advanced MEMS techniques. Despite its appreciable performance, the actual cricket filiform hairs outperform artificial hair sensors by several orders in sensitivity. Nevertheless, more careful look at the anatomy and physiology of the cricket cerci provides new directions to be explored with MEMS technologies to realize higher sensitivities on a par with crickets’. This paper aims to provide an overview of comparisons between the actual and artificial hair sensors in terms of sensitivity, structural functionalities and robustness and draws out constructive insights to optimize sensor performance

Cricket Paralysis Virus Threatens Cricket Farm Business

Crickets are a vital source of protein for many human and animals such as frogs, geckos, lizards and are starting to make a debut as an ingredient in dog food. When crickets are consumed it is vital the crickets are free of disease (Dunn). One disease that crickets are susceptible to is the cricket paralysis virus. Cricket paralysis virus (CPV) can “infect several insect orders such as Diptera, Lepidoptera, Orthoptera, Hemiptera and Hymenoptera, as well as a diverse range of cultured insect cells”(King). The cricket paralysis virus belongs to the family of viruses classified as Dicistroviridae. Dicistroviridae viruses can be characterized as “small enveloped viruses with monopartite, linear, and positive sense RNA genomes”(Valles). A collection of cricket samples from a cricket farm was sent to the lab to be tested for the cricket paralysis virus. If the crickets test positive for the cricket paralysis virus then the cricket farm may be forced to shut down. However, the results of the experiment were negative for the virus. These results are crucial because they impact the people or animals that consume these crickets, the fate of the business that produces the crickets, and contributes to more experiments related to the cricket paralysis virus

Biomimetic flow-sensor arrays based on the filiform hairs on the cerci of crickets

In this paper we report on the latest developments in biomimetic flow-sensors based on the flow sensitive mechano-sensors of crickets. Crickets have one form of acoustic sensing evolved in the form of mechanoreceptive sensory hairs. These filiform hairs are highly perceptive to low-frequency sound with energy sensitivities close to thermal threshold. Arrays of artificial hair sensors have been fabricated using a surface micromachining technology to form suspended silicon nitride membranes and double-layer SU-8 processing to form 1 mm long hairs. Previously, we have shown that these hairs are sensitive to low-frequency sound, using a laser vibrometer setup to detect the movements of the nitride membranes. We have now realized readout electronics to detect the movements capacitively, using electrodes integrated on the membranes

Mechanisms of high-frequency song generation in brachypterous crickets and the role of ghost frequencies

Sound production in crickets relies on stridulation, the well-understood rubbing together of a pair of specialised wings. As the file of one wing slides over the scraper of the other, a series of rhythmic impacts cause harmonic oscillations, usually resulting in the radiation of pure tones delivered at low frequencies (2-8 kHz). In the short winged crickets of the Lebinthini tribe, acoustic communication relies on signals with remarkably high frequencies (> 8 kHz) and rich harmonic content. Using several species of the subfamily Eneopterinae, we characterise the morphological and mechanical specialisations supporting the production of high frequencies, and demonstrate that higher harmonics are exploited as dominant frequencies. These specialisations affect the structure of the stridulatory file, the motor control of stridulation and the resonance of the sound radiator. We place these specialisations in a phylogenetic framework and show that they serve to exploit high frequency vibrational modes pre-existing in the phylogenetic ancestor. In Eneopterinae, the lower frequency components are harmonically related to the dominant peak, suggesting they are relicts of ancestral carrier frequencies. Yet, such ghost frequencies still occur in the wings' free resonances, highlighting the fundamental mechanical constraints of sound radiation. These results support the hypothesis that such high frequency songs evolved stepwise, by a form of punctuated evolution which could be related to functional constraints, rather than by the progressive increase of the ancestral fundamental frequency

Indiana Ensifera (Orthopera)

(excerpt) A total of 67 species of long-horned grasshoppers and crickets were reported to occur in Indiana by Blatchley (1903) in his Orthoptera of Indiana. Distributional information concerning thek species was sparse and has not been significantly supplemented since that time. Subsequent works which have dealt either heavily or exclusively with the Indiana fauna include Fox (1915), Blatchley (1920), Cantrall and Young (1954), and Young and Cantrall(1956)

The Singing Insects of Michigan

Excerpt: The so-called singing insects are all those that make loud, rhythmical noises. They include members of three groups of Orthoptera (Gryllidae, Tettigoniidae, and Acridoidea) and one family of Homoptera (Cicadidae). There are about 300 noisy species in these four groups in eastern North America, perhaps a thousand in all of North America, and 25-30 thousand in the entire world. Only about 1000 of the world species have been studied in any detail, mostly in North America, Europe, Japan, and Australia

Learning from Crickets: Artificial Hair-Sensor Array Developments

We have successfully developed biomimetic flowsensitive hair-sensor arrays taking inspiration from mechanosensory hairs of crickets. Our current generation of sensors achieves sub mm/s threshold air-flow sensitivity for single hairs operating in a bandwidth of a few hundred Hz and is the result of a few iterations in which the natural system (i.e. crickets filiform hair based mechano-sensors) have shown ample guidance to optimization. Important clues with respect to mechanical design, aerodynamics, viscous coupling effects and canopy based signal processing have been used during the course of our research. It is only by consideration of all these effects that we now may start thinking of systems performing a “flow-camera” function as found in nature in a variety of species

A Review of the Genus \u3ci\u3eGryllus\u3c/i\u3e (Orthoptera: Gryllidae), With a New Species From Korea

Gryllus is the most widely distributed genus of the Tribe Gryllini, and may be the largest; it includes 69 described species occupying most of the New World, Africa, and Europe, and much of Asia. A new species from Korea significantly extends the known range of the genus

Cricket antennae shorten when bending (Acheta domesticus L.).

Insect antennae are important mechanosensory and chemosensory organs. Insect appendages, such as antennae, are encased in a cuticular exoskeleton and are thought to bend only between segments or subsegments where the cuticle is thinner, more flexible, or bent into a fold. There is a growing appreciation of the dominating influence of folds in the mechanical behavior of a structure, and the bending of cricket antennae was considered in this context. Antennae will bend or deflect in response to forces, and the resulting bending behavior will affect the sensory input of the antennae. In some cricket antennae, such as in those of Acheta domesticus, there are a large number (>100) of subsegments (flagellomeres) that vary in their length. We evaluated whether these antennae bend only at the joints between flagellomeres, which has always been assumed but not tested. In addition we questioned whether an antenna undergoes a length change as it bends, which would result from some patterns of joint deformation. Measurements using light microscopy and SEM were conducted on both male and female adult crickets (Acheta domesticus) with bending in four different directions: dorsal, ventral, medial, and lateral. Bending occurred only at the joints between flagellomeres, and antennae shortened a comparable amount during bending, regardless of sex or bending direction. The cuticular folds separating antennal flagellomeres are not very deep, and therefore as an antenna bends, the convex side (in tension) does not have a lot of slack cuticle to "unfold" and does not lengthen during bending. Simultaneously on the other side of the antenna, on the concave side in compression, there is an increasing overlap in the folded cuticle of the joints during bending. Antennal shortening during bending would prevent stretching of antennal nerves and may promote hemolymph exchange between the antenna and head