Campaniform sensilla: Another vibration receptor in the crab leg

A detailed mapping and description of campaniform sensilla on the wing and haltere of Drosophila melanogaster is provided. Six types of sensilla are distinguished. Similarities in the pattern of their distribution on the dorsal and ventral surfaces of each appendage, as well as between the wing and haltere, are apparent. These data are used to assess the quality of homeotic transformation in several mutants of the bithorax complex in which the halteres are transformed into wings. Flies homozygous for abxbx3pbx produce a complete inventory of wing sensilla on the homeotic appendage. In abx, bx3 and bx3pbx homozygotes the transformation of haltere into wing is incomplete, and each mutant shows characteristic fields of haltere and wing sensilla. It appears that specific regions of the anterior haltere compartment require different combinations of mutant alleles to produce a distinct homeotic transformation. Furthermore, the pbx mutation appears to influence expression of the bx3 mutation within the anterior compartment.

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Proprioception In Insects

Journal of Experimental Biology ◽

10.1242/jeb.15.1.114 ◽

1938 ◽

Vol 15 (1) ◽

pp. 114-131 ◽

Cited By ~ 6

Author(s):

J. W. S. PRINGLE

Keyword(s):

Contact Pressure ◽

Mode Of Action ◽

Mechanical Model ◽

Campaniform Sensilla ◽

Chemical Substances ◽

Parallel Orientation ◽

Model Based ◽

Vertebrate Limb ◽

Olfactory Stimuli ◽

Anatomical Arrangement

1. The campaniform sensilla on the legs of Periplaneta are similar in action to those on the palps, and respond to strains in the cuticle. 2. They are arranged in groups at the joints, with parallel orientation of the sensilla of a group. 3. Tests with various chemical substances show a complete absence of sensitivity to olfactory stimuli. 4. A theory is given of the mode of action of the sensilla in terms of a mechanical model based on their observed structure. Each group of parallel sensilla should act as a unit, responding to those forces which have a compression component of shear in the direction of their long diameters. 5. This theory makes it possible to predict the behaviour of the sensilla from their anatomical arrangement. Most if not all the groups on the legs are so arranged as to be sensitive to the forces present when the insect is standing on the ground. 6. The sensilla probably provide the basis for the sense of contact pressure postulated by Holst (1935), Hoffmann (1933), Crozier & Stier (1928-9), Fraenkel (1932) and others. 7. Comparison of this proprioceptive mechanism with that of the vertebrate limb reveals an absence of qualitative sensitivity that may have an important bearing on the question of the evolution of behaviour.

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Neural evidence supports a dual sensory-motor role for insect wings

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2017.0969 ◽

2017 ◽

Vol 284 (1862) ◽

pp. 20170969 ◽

Cited By ~ 18

Author(s):

Brandon Pratt ◽

Tanvi Deora ◽

Thomas Mohren ◽

Thomas Daniel

Keyword(s):

Flight Control ◽

Information Acquisition ◽

Receptive Fields ◽

Mechanical Stimulus ◽

Sensory Function ◽

Computational Techniques ◽

Campaniform Sensilla ◽

Specific Stimulus ◽

Processing Times ◽

Stimulus Features

Flying insects use feedback from various sensory modalities including vision and mechanosensation to navigate through their environment. The rapid speed of mechanosensory information acquisition and processing compensates for the slower processing times associated with vision, particularly under low light conditions. While halteres in dipteran species are well known to provide such information for flight control, less is understood about the mechanosensory roles of their evolutionary antecedent, wings. The features that wing mechanosensory neurons (campaniform sensilla) encode remains relatively unexplored. We hypothesized that the wing campaniform sensilla of the hawkmoth, Manduca sexta, rapidly and selectively extract mechanical stimulus features in a manner similar to halteres. We used electrophysiological and computational techniques to characterize the encoding properties of wing campaniform sensilla. To accomplish this, we developed a novel technique for localizing receptive fields using a focused IR laser that elicits changes in the neural activity of mechanoreceptors. We found that (i) most wing mechanosensors encoded mechanical stimulus features rapidly and precisely, (ii) they are selective for specific stimulus features, and (iii) there is diversity in the encoding properties of wing campaniform sensilla. We found that the encoding properties of wing campaniform sensilla are similar to those for haltere neurons. Therefore, it appears that the neural architecture that underlies the haltere sensory function is present in wings, which lends credence to the notion that wings themselves may serve a similar sensory function. Thus, wings may not only function as the primary actuator of the organism but also as sensors of the inertial dynamics of the animal.

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Intra- and intersegmental pathways active during walking in the locust

Proceedings of the Royal Society of London Series B Biological Sciences ◽

10.1098/rspb.1983.0040 ◽

1983 ◽

Vol 218 (1212) ◽

pp. 287-308 ◽

Cited By ~ 12

Keyword(s):

Pattern Generator ◽

Short Latency ◽

Chordotonal Organ ◽

Campaniform Sensilla ◽

Flexor Muscle ◽

Walking Pattern ◽

Excitatory Pathways ◽

Motor Information ◽

Antagonist Group ◽

Stimulation Of

Electrical stimulation of femoral chordotonal organs, trochanteral campaniform sensilla, trochanteral hairplates and tibial muscles was used to reveal neuronal pathways active in the standing and walking locust. Responses evoked by campaniform sensilla stimulation were also recorded intracellularly from flexor motoneurons in fixed animals. The trochanteral campaniform sensilla have a direct short-latency connection to tibial extensor motoneurons and more labile, longer-latency, excitatory and inhibitory connections to the tibial flexors of the same leg. Trains of stimuli to the trochanteral campaniform sensilla initiated an early swing only if the stimulation was timed to occur during late stance. The importance of this type of load afference in step-timing was demonstrated by amputating the mesothoracic leg: the stump oscillated at a higher than normal frequency. Addition of a prosthetic leg restored normal stepping. Stimulation of the femoral chordotonal organ revealed short latency, excitatory pathways to both extensor and flexor motoneurons of the same leg. Trains of stimuli to the organ initiated early swing of this leg if applied late in stance. Stimulation of either the flexor or the extensor muscle evoked a response in the antagonist group of the same leg which was abolished by amputation distal to the muscles. The flexor-evoked response functioned only in the presence of load afference. The same was found for the pathway to the walking-pattern generator activated by stimulating the flexor muscle. Stimulation of the posterior trochanteral hairplates often evoked a swing but the latency could be several hundred milliseconds. Deafferentation showed that sensory input is critical for interganglionic coordination. There are labile polysynaptic excitatory and inhibitory pathways from the trochanteral campaniform senilla to the flexor motoneurons of the adjacent leg. Trains could evoke an early swing in the adjacent leg if time to occur during late stance and if the homonymous leg itself was not in late stance. Stimulation of the chordotonal organ revealedfast-conducting stable pathways to the flexors and extensors of all the ipsilateral legs. Trains could induce an early swing if timed late in the stance of the adjacent leg and if the homonymous leg itself was not in late stance. Amputation of the adjacent leg had no effect on the direct evoked responses but swing could not be evoked unless a prosthesis was added. Load afference is necessary for the effectiveness of the intersegmental chordotonal input to the walkingpattern generator. Stimulation of the trochanteral hairplate revealed no intersegmental pathway. The intra- and intersegmental pathways revealed by our experiments are summarized diagrammatically. The results suggest that an important function of load afference is to modulate the flow of proprioceptive and motor information within the walking-pattern generator.

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