Serial homologies of the motor neurons of the dorsal intersegmental muscles of the cockroach, Periplaneta americana (L.)

Abstract

The types and locations of serially homologous motor neurons of the dorsal muscles in the cockroach Periplaneta americana remain rather constant regardless of the various adaptations of their muscles or the fusion of ganglia. However, the size and number of neurons do vary according to the development of the muscles they innervate. Neurons in four distinctive locations, two ipsisegmental and two antesegmental, innervate the dorsal longitudinal (DL) muscles in most segments. One of the ipsisegmental neurons (DLC) is common to all of the DL muscles of a segment and probably has a modulatory function. The dorsal oblique (DO) muscles of most segments have neurons in two antesegmental positions. One of these, an antesegmental, contralateral neuron, innervates both DO and DL muscles in each segment and is also probably modulatory. One neuron (DOC) of the prothoracic ganglion is the principal exception to the constancy of these serially homologous neurons. This neuron appears to be homologous to the DLC neurons of other segments but innervates the DO rather than the DL muscles.

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 peripheral nerve pattern is conserved also with respect to related taxa of Orthoptera (Honegger et al, 1984), Embioptera (Rähle, 1970), and Blattodea (Davis, 1983), where the nerves N. ant. SOG, N. post.…”

“…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.…”

Modulation of contractility and basic tonus in two serially homologous muscles in the cricket Teleogryllus oceanicus

“…Although it is unknown if the abdominal DLM motoneurons contain proctolin, several neurons in the same general location as the abdominal DLM motoneurons (Davis, 1983) exhibit proctolin-like immunoreactivity ). An additional indication that proctolin is involved in abdominal muscle function is the localization of a proctolin-1ike peptide in several abdominal muscles of the Colorado potato beetle (Veenstra et al, 1985) and Drosophila .…”

“…Proctolin has been localized in motoneurons which control postural movements in insects and crayfish (O' Wordon et al, 1985). The abdominal DLM appears to be a candidate for proctolin modulation since proctolin-like immunoreactivity has been localized in neurons located in the same area as the motoneurons for the abdominal DLM (Davis, 1983). In addition, a proctolin-like substance has been localized in several abdominal muscles in two species of insects (Veenstra et al, 1985;.…”