Revisiting the Labial Pit Organ Pathway in the Noctuid Moth, Helicoverpa armigera
Lepidopteran species detect CO2 via a specialized organ located on the peripheral segment of the labial palps, the labial palp pit organ (LPO). Based on tracing of LPO sensory neurons targeting one distinct antennal-lobe glomerulus, Kent and her colleagues described the projections originating from...
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doaj-07dc03421ec64cac836604e90af786f32020-11-25T02:35:17ZengFrontiers Media S.A.Frontiers in Physiology1664-042X2020-03-011110.3389/fphys.2020.00202510478Revisiting the Labial Pit Organ Pathway in the Noctuid Moth, Helicoverpa armigeraPramod KC0Xi Chu1Pål Kvello2Xin-Cheng Zhao3Gui-Rong Wang4Bente Gunnveig Berg5Chemosensory Laboratory, Department of Psychology, Norwegian University of Science and Technology (NTNU), Trondheim, NorwayChemosensory Laboratory, Department of Psychology, Norwegian University of Science and Technology (NTNU), Trondheim, NorwayDepartment of Teacher Education, Norwegian University of Science and Technology (NTNU), Trondheim, NorwayDepartment of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, ChinaState Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, ChinaChemosensory Laboratory, Department of Psychology, Norwegian University of Science and Technology (NTNU), Trondheim, NorwayLepidopteran species detect CO2 via a specialized organ located on the peripheral segment of the labial palps, the labial palp pit organ (LPO). Based on tracing of LPO sensory neurons targeting one distinct antennal-lobe glomerulus, Kent and her colleagues described the projections originating from the LPO in the sphinx moth as “an accessory olfactory pathway in Lepidoptera” already in the 1980 ties. In spite of similar reports from studies of other lepidopteran species, however, it has been an unresolved issue whether additional termination areas of the labial nerve, such as the gnathal ganglion (GNG) and the ventral nerve cord, are actually output sites of LPO neurons. Since the previous studies have interpreted slightly differently about the projection pattern occurring from the classical mass staining, we performed selective mass staining from the inside of the pit and from the outer surface of the peripheral palp. The results demonstrated that the LPO sensory neurons project exclusively to the LPO glomerulus (LPOG), whereas the non-LPO sensory neurons target the GNG and the ventral nerve cord. Additional iontophoretic staining of individual LPO sensory neurons, performed from the LPO and the LPOG, showed three morphological neuron types: one bilateral targeting the LPOG in both antennal lobes, one unilateral targeting the ipsilateral LPOG only, and one contralateral targeting the LPOG in the other antennal lobe. Finally, to explore putative differences in the projection pattern of neurons housed by two previously reported sensillum types in the pit, i.e., hair-shaped sensilla located distally and club-shaped sensilla located proximally, we performed mass staining from two different levels of the peripheral palp. We found a projection pattern implying stronger innervation of the ipsi- than the contralateral LPOG in both staining experiments.https://www.frontiersin.org/article/10.3389/fphys.2020.00202/fullLPO sensory pathwayLPOGantennal lobeindividual sensory neuronsiontophoretic staining |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Pramod KC Xi Chu Pål Kvello Xin-Cheng Zhao Gui-Rong Wang Bente Gunnveig Berg |
spellingShingle |
Pramod KC Xi Chu Pål Kvello Xin-Cheng Zhao Gui-Rong Wang Bente Gunnveig Berg Revisiting the Labial Pit Organ Pathway in the Noctuid Moth, Helicoverpa armigera Frontiers in Physiology LPO sensory pathway LPOG antennal lobe individual sensory neurons iontophoretic staining |
author_facet |
Pramod KC Xi Chu Pål Kvello Xin-Cheng Zhao Gui-Rong Wang Bente Gunnveig Berg |
author_sort |
Pramod KC |
title |
Revisiting the Labial Pit Organ Pathway in the Noctuid Moth, Helicoverpa armigera |
title_short |
Revisiting the Labial Pit Organ Pathway in the Noctuid Moth, Helicoverpa armigera |
title_full |
Revisiting the Labial Pit Organ Pathway in the Noctuid Moth, Helicoverpa armigera |
title_fullStr |
Revisiting the Labial Pit Organ Pathway in the Noctuid Moth, Helicoverpa armigera |
title_full_unstemmed |
Revisiting the Labial Pit Organ Pathway in the Noctuid Moth, Helicoverpa armigera |
title_sort |
revisiting the labial pit organ pathway in the noctuid moth, helicoverpa armigera |
publisher |
Frontiers Media S.A. |
series |
Frontiers in Physiology |
issn |
1664-042X |
publishDate |
2020-03-01 |
description |
Lepidopteran species detect CO2 via a specialized organ located on the peripheral segment of the labial palps, the labial palp pit organ (LPO). Based on tracing of LPO sensory neurons targeting one distinct antennal-lobe glomerulus, Kent and her colleagues described the projections originating from the LPO in the sphinx moth as “an accessory olfactory pathway in Lepidoptera” already in the 1980 ties. In spite of similar reports from studies of other lepidopteran species, however, it has been an unresolved issue whether additional termination areas of the labial nerve, such as the gnathal ganglion (GNG) and the ventral nerve cord, are actually output sites of LPO neurons. Since the previous studies have interpreted slightly differently about the projection pattern occurring from the classical mass staining, we performed selective mass staining from the inside of the pit and from the outer surface of the peripheral palp. The results demonstrated that the LPO sensory neurons project exclusively to the LPO glomerulus (LPOG), whereas the non-LPO sensory neurons target the GNG and the ventral nerve cord. Additional iontophoretic staining of individual LPO sensory neurons, performed from the LPO and the LPOG, showed three morphological neuron types: one bilateral targeting the LPOG in both antennal lobes, one unilateral targeting the ipsilateral LPOG only, and one contralateral targeting the LPOG in the other antennal lobe. Finally, to explore putative differences in the projection pattern of neurons housed by two previously reported sensillum types in the pit, i.e., hair-shaped sensilla located distally and club-shaped sensilla located proximally, we performed mass staining from two different levels of the peripheral palp. We found a projection pattern implying stronger innervation of the ipsi- than the contralateral LPOG in both staining experiments. |
topic |
LPO sensory pathway LPOG antennal lobe individual sensory neurons iontophoretic staining |
url |
https://www.frontiersin.org/article/10.3389/fphys.2020.00202/full |
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