Demonstration of functional connectivity of the flight motor system in all stages of the locust

Stevenson, Paul A.; Kutsch, W.

doi:10.1007/bf00606089

Cited by 81 publications

(43 citation statements)

References 36 publications

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“…Grasshoppers are among the approximately 5% of insects that are not completely metamorphic, and their hatchlings closely resemble miniature adults. In grasshoppers, it appears that neurodevelopment is completed embryonically (Bate, 1976;Shepherd and Bate, 1990), and the precocious expression of adult-only behaviors such as flight and oviposition (Stevenson and Kutsch, 1989;Thompson and Roosevelt, 1998) is consistent with this observation. By hatching, segmental and regional differences are obvious in the nervous system of grasshoppers, with for example, 2,000 neurons in the thoracic ganglion that controls the hind wings and jumping legs, and only about 400 in a small pregenital abdominal ganglion.…”

Section: Discussionmentioning

confidence: 52%

Efferent neurons and specialization of abdominal segments in grasshoppers

Thompson¹,

Sivanesan²,

Campbell³

et al. 1999

J. Comp. Neurol.

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Section: Discussionmentioning

confidence: 52%

Efferent neurons and specialization of abdominal segments in grasshoppers

Thompson¹,

Sivanesan²,

Campbell³

et al. 1999

J. Comp. Neurol.

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“…Octopamine is often correlated with arousal state in insects (Davenport and Evans, 1984;Parker, 1996). It also plays an important role in locust flight (Stevenson and Kutsch, 1988;Parker, 1996;Pfluger and Duch, 2000). Released at the onset of flight, from DUM neurons in the locust segmental ganglia into the hemolymph, octopamine has a variety of effects on the central and peripheral nervous systems (Ramirez et al, 1989;Parker, 1996;Pfluger and Duch, 2000).…”

Section: Discussionmentioning

confidence: 97%

Neural correlates to flight‐related density‐dependent phase characteristics in locusts

2003

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Locust phase polymorphism is an extreme example of behavioral plasticity; in response to changes in population density, locusts dramatically alter their behavior. These changes in behavior facilitate the appearance of various morphological and physiological phase characteristics. One of the principal behavioral changes is the more intense flight behavior and improved flight performance of gregarious locusts compared to solitary ones. Surprisingly, the neurophysiological basis of the behavioral phase characteristics has received little attention. Here we present density-dependent differences in flight-related sensory and central neural elements in the desert locust. Using techniques already established for gregarious locusts, we compared the response of locusts of both phases to controlled wind stimuli. Gregarious locusts demonstrated a lower threshold for wind-induced flight initiation. Wind-induced spiking activity in the locust tritocerebral commissure giants (TCG, a pair of identified interneurons that relay input from head hair receptors to thoracic motor centers) was found to be weaker in solitary locusts compared to gregarious ones. The solitary locusts' TCG also demonstrated much stronger spike frequency adaptation in response to wind stimuli. Although the number of forehead wind sensitive hairs was found to be larger in solitary locusts, the stimuli conveyed to their flight motor centers were weaker. The tritocerebral commissure dwarf (TCD) is an inhibitory flight-related interneuron in the locust that responds to light stimuli. An increase in TCD spontaneous activity in dark conditions was significantly stronger in gregarious locusts than in solitary ones. Thus, phase-dependent differences in the activity of flight-related interneurons reflect behavioral phase characteristics.

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“…For example, in hemimetabolous insects the neural networks for flight are present at preflight stages. Al-though flight behavior is expressed only in the adult, it is possible, using specific stimulation, to trigger components of adult flight in early larval stages (Stevenson and Kutsch, 1988). Moreover, work on many vertebrates systems, such lamprey (Cohen et al, 1990), fish (Batty, 1984), amphibians (Kahn and Roberts, 1982), birds (Bekoff, 1992), and mammals (Robinson and Smotherman, 1992) also indicate that the networks involved in rhythmic motor activities are constructed early in development.…”

Section: Discussionmentioning

confidence: 99%

Functional differentiation of adult neural circuits from a single embryonic network

Casasnovas¹,

Meyrand²

1995

J. Neurosci.

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The stomatogastric nervous system (STNS) of adult lobsters and crabs generates a number of different rhythmic motor patterns which control different regional movements of the foregut. Since these output patterns are generated by discrete neural networks that, in the adult, are well characterized in terms of synaptic and cellular properties, this system constitutes an ideal model for exploring the mechanisms underlying the ontogeny of neural network organization. The foregut and its rhythmic motor patterns were studied in in vitro STNS nerve-muscle preparations of the embryo and different larval stages of the lobster Homarus gammarus. The development of Homarus comprises a long embryonic stage in ovo followed by three pelagic larval stages prior to the onset of benthic life. During these stages the foregut itself develops slowly from a simple ectodermal invagination that occurs in the embryo. During successive larval stages it progressively acquires all the specialized structures and shape of the adult foregut. In contrast, the STNS is morphologically recognizable at early embryonic stages. In all recorded stages the STNS spontaneously expresses rhythmic motor activity. During development, this activity is progressively restructured, beginning with a single rhythmic motor pattern in the embryo where all the stomodeal muscles are strongly coordinated. In subsequent stages, however, this single pattern is progressively subdivided to give rise eventually to the three discrete rhythmic motor patterns characteristic of the adult STNS. Our data suggest that rather than a dismantling of redundant embryonic and larval neural networks, the different adult networks emerge as a progressive partitioning of discrete circuits from a single embryonic network.

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Demonstration of functional connectivity of the flight motor system in all stages of the locust

Cited by 81 publications

References 36 publications

Efferent neurons and specialization of abdominal segments in grasshoppers

Efferent neurons and specialization of abdominal segments in grasshoppers

Neural correlates to flight‐related density‐dependent phase characteristics in locusts

Functional differentiation of adult neural circuits from a single embryonic network

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