Structure and spatial pattern of the sensilla of the body segments of insect larvae

Green, Patricia; Hartenstein, Volker

doi:10.1002/(sici)1097-0029(19971215)39:6<470::aid-jemt2>3.0.co;2-i

“…From their external structure and ultrastructure, several es organs resemble tactile receptors and are likely to be equivalent to the more rigid, tactile hairs of hard‐bodied insects (Hartenstein, 1988). Some es organs more closely resemble the campaniform sensilla of hard‐bodied insects (Green and Hartenstein, 1997). In general, insect campaniform sensilla are proprioceptive and their axons project into intermediate neuropil (Merritt and Murphey, 1992).…”

Section: Discussionmentioning

confidence: 99%

Central projections ofDrosophila sensory neurons in the transition from embryo to larva

Schrader

¹

,

Merritt

²

2000

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Sensory axons of different sensory modalities project into typical domains within insect ganglia. Tactile and gustatory axons project into a ventral layer of neuropil and proprioceptive afferents, including chordotonal axons, into an intermediate or dorsal layer. Here, we describe the central projections of sensory neurons in the first instar Drosophila larva, relating them to the projection of the same sensory afferents in the embryo and to sensory afferents of similar type in other insects. Several neurons show marked morphologic changes in their axon terminals in the transition between the embryo and larva. During a short morphogenetic period late in embryogenesis, the axon terminals of the dorsal bipolar dendrite stretch receptor change their shape and their distribution within the neuromere. In the larva, external sense organ neurons (es) project their axons into a ventral layer of neuropil. Chordotonal sensory neurons (ch) project into a slightly more dorsal region that is comparable to their projection in adults. The multiple dendrite (md) neurons show two distinctive classes of projection. One group of md neurons projects into the ventral-most neuropil region, the same region into which es neurons project. Members of this group are related by lineage to es neurons or share a requirement for expression of the same proneural gene during development. Other md neurons project into a more dorsal region. Sensory receptors projecting into dorsal neuropil possibly provide proprioceptive feedback from the periphery to central motorneurons and are candidates for future genetic and cellular analysis of simple neural circuitry.

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“…From their external structure and ultrastructure, several es organs resemble tactile receptors and are likely to be equivalent to the more rigid, tactile hairs of hardbodied insects (Hartenstein, 1988). Some es organs more closely resemble the campaniform sensilla of hard-bodied insects (Green and Hartenstein, 1997). In general, insect campaniform sensilla are proprioceptive and their axons project into intermediate neuropil (Merritt and Murphey, 1992).…”

Section: Modality Specific Layeringmentioning

confidence: 99%

Central projections of Drosophila sensory neurons in the transition from embryo to larva

Schrader

¹

,

Merritt

²

2000

View full text Add to dashboard Cite

Sensory axons of different sensory modalities project into typical domains within insect ganglia. Tactile and gustatory axons project into a ventral layer of neuropil and proprioceptive afferents, including chordotonal axons, into an intermediate or dorsal layer. Here, we describe the central projections of sensory neurons in the first instar Drosophila larva, relating them to the projection of the same sensory afferents in the embryo and to sensory afferents of similar type in other insects. Several neurons show marked morphologic changes in their axon terminals in the transition between the embryo and larva. During a short morphogenetic period late in embryogenesis, the axon terminals of the dorsal bipolar dendrite stretch receptor change their shape and their distribution within the neuromere. In the larva, external sense organ neurons (es) project their axons into a ventral layer of neuropil. Chordotonal sensory neurons (ch) project into a slightly more dorsal region that is comparable to their projection in adults. The multiple dendrite (md) neurons show two distinctive classes of projection. One group of md neurons projects into the ventral-most neuropil region, the same region into which es neurons project. Members of this group are related by lineage to es neurons or share a requirement for expression of the same proneural gene during development. Other md neurons project into a more dorsal region. Sensory receptors projecting into dorsal neuropil possibly provide proprioceptive feedback from the periphery to central motorneurons and are candidates for future genetic and cellular analysis of simple neural circuitry.

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“…The es and ch organs are composed of one or several neurons associated with accessory cells. The es organs transduce mechanosensory, chemosensory and possibly stretch information (Green and Hartenstein 1997), while the ch organs are thought to function as stretch or proprio-receptors (Jan and Jan 1993). The md neurons do not have any accessory cells and may function as touch-, proprio-, chemo-, thermo-, or nocireceptors Liu et al 2003;Tracey et al 2003), or even as non-sensory secretory neurons (Hewes et al 2003).…”

Section: Introductionmentioning

confidence: 99%

Evolution of the larval peripheral nervous system in Drosophila species has involved a change in sensory cell lineage

Orgogozo

¹

,

Schweisguth

²

2004

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A key challenge in evolutionary biology is to identify developmental events responsible for morphological changes. To determine the cellular basis that underlies changes in the larval peripheral nervous system (PNS) of flies, we first described the PNS pattern of the abdominal segments A1-A7 in late embryos of several fly species using antibody staining. In contrast to the many variations reported previously for the adult PNS pattern, we found that the larval PNS pattern has remained very stable during evolution. Indeed, our observation that most of the analysed Drosophilinae species exhibit exactly the same pattern as Drosophila melanogaster reveals that the pattern observed in D. melanogaster embryos has remained constant for at least 40 million years. Furthermore, we observed that the PNS pattern in more distantly related flies (Calliphoridae and Phoridae) is only slightly different from the one in D. melanogaster. A single difference relative to D. melanogaster was identified in the PNS pattern of the Drosophilinae fly D. busckii, the absence of a specific external sensory organ. Our analysis of sensory organ development in D. busckii suggests that this specific loss resulted from a transformation in cell lineage, from a multidendritic-neuron-external-sensory-organ lineage to a multidendritic-neuron-solo lineage.

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Structure and spatial pattern of the sensilla of the body segments of insect larvae

Cited by 16 publications

References 25 publications

Central projections ofDrosophila sensory neurons in the transition from embryo to larva

Central projections ofDrosophila sensory neurons in the transition from embryo to larva

Central projections of Drosophila sensory neurons in the transition from embryo to larva

Evolution of the larval peripheral nervous system in Drosophila species has involved a change in sensory cell lineage

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