A comparative study of neck muscle motor neurons in a cricket and a locust

Abstract

The gross morphology of the neck muscles of a cricket (Gryllus campestris) and their innervation are described and compared with a locust (Schistocerca gregaria). The motor neurons innervating the neck muscles were stained in crickets and locusts with cobalt chloride introduced via the nerve endings in the muscle. The two species show overall similarities, not only in position of the neck motor neurons in suboesophageal, prothoracic, and mesothoracic ganglia but also in motor neuron morphology. However, muscle 60 in the cricket is innervated by a unique motor neuron with its axon in prothoracic nerve 3, instead of sharing motor neurons in suboesophageal nerve 8 and mesothoracic nerve 1 with muscle 59, as in locust. Muscle 62 has the same attachments and innervation with similar motor neurons in cricket and locust but a different mechanical function in the two species. The findings are discussed with respect to possible segmental homologies and to the origins of the muscles as either dorso-ventral or longitudinal. As several muscles share the same motor neurons, we suggest that neck muscle function be described in terms of "behavioural units of action."

Gaze control in the blowfly Calliphora: a multisensory, two-stage integration process

“…Most remarkably, these pathways have been demonstrated by the passage of cobalt ions across one or even two contiguous neurons. 12,35 In other neurons in the fly, this cell-specific transneuronal cobalt labelling is associated with gap junctions, 40 another indication that the haltere pathway is a particularly fast one (see Figure 4). (Figure 3a) is mediated through the compound eyes and requires a nonlinear interaction between two adjacent inputs.…”

Multiple Identified Neurons and Peripheral Nerves Innervating the Prothoracic Defense Glands in Stick Insects Reveal Evolutionary Conserved and Novel Elements of a Chemical Defense System

“…The terminology of peripheral nerves follows Marquardt (1940) and Honegger et al (1984). The terminology for thoracic muscles follows Friedrich and Beutel (2008) and Wipfler et al (2015) for the neopteran muscle groundplan in the thorax.…”

“…SOG innervation. We use axonal tracing of individual nerve branches from the Nervus anterior SOG to differentiate the neuronal innervation of the defense gland and of the dorsal longitudinal muscles (or neck muscles, Honegger et al, 1984). Comparison of these motoneurons in stick insects to homologous neurons in related species of cockroaches (Davis, 1983) and locusts (Altman and Kien, 1979;Honegger et al, 1984) reveals neurons which have evolved with the development of the defense glands.…”

“…We use axonal tracing of individual nerve branches from the Nervus anterior SOG to differentiate the neuronal innervation of the defense gland and of the dorsal longitudinal muscles (or neck muscles, Honegger et al, 1984). Comparison of these motoneurons in stick insects to homologous neurons in related species of cockroaches (Davis, 1983) and locusts (Altman and Kien, 1979;Honegger et al, 1984) reveals neurons which have evolved with the development of the defense glands. This comparison of identified neurons (Goodman et al, 1979;Hoyle, 1983;Arbas et al, 1991;Kutsch and Breidbach, 1994) allows to identify the evolutionary novel nerve cells in stick insects which underlie chemical defense.…”

Origin and peripheral distribution of the thoracic and abdominal median nerves in the fifth instar larva of the silkworm, Bombyx mori (Lepidoptera: Bombycidae)

“…The investigations pertaining to the origin, peripheral distribution and innervation patterns of these nerves will contribute to our understanding of the basic tenets of the nerve-muscle anatomy and insect physiology. In the last decade, significant efforts have been made to map the nerve topography and segmental musculature of a variety of insects such as Bombyx mori (Sivaprasad and Muralimohan, 1998), Culiseta inormata (Owen, 2006), Nomia melanderi (Youssef, 2005 a, b), Apis mellifera (Masuko, 2005;Shankland, 2005), Drosophila and Calliphora (Sink, 2006;Spieb et al, 2007), Gryllus campestris and Periplaneta americana (Honegger et al, 2004and Alsop, 2005, Denburg and Fulop, 2005, Davis, 2005, Ready and Josephson, 2005a,b and Klass, 2008. More significantly, some earlier investigations (Hoyle, 1959;Miller, 1960 andLewis et al, 1973), devoted to trace the pathways and innervations of unpaired median nerves and to establish their physical association with the spiracular muscles that control tracheal respiration through their regulatory influence on the opening and closing movements of the spiracles in insects.…”