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Cao S, Liu Y, Wang B, Wang G. A single point mutation causes one-way alteration of pheromone receptor function in two Heliothis species. iScience 2021; 24:102981. [PMID: 34485863 PMCID: PMC8403742 DOI: 10.1016/j.isci.2021.102981] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 07/12/2021] [Accepted: 08/11/2021] [Indexed: 11/04/2022] Open
Abstract
The sex pheromone processing system of moths has been a major focus of research on olfaction and speciation, as it is highly specific and closely related to reproductive isolation. The two noctuid moths Heliothis virescens and Heliothis subflexa have been used as a model for deciphering the mechanisms underlying differentiation in pheromone communication, but no information exist regarding the functions of the pheromone receptors (PRs) of H. subflexa. Here, we functionally characterized all candidate PRs of H. subflexa, and found that only the response profile of OR6 differed between the two species. Through domain swapping and site-directed mutation followed by functional characterization, we identified a critical amino acid in OR6 caused a one-way alteration in specificity. This result suggests HsubOR6 evolved from an ancestral OR6 gene with a HvirOR6-like function and implies that the evolutionary direction of the receptor specificity was from the H. virescens-like pattern to H. subflexa-like pattern.
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Affiliation(s)
- Song Cao
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518120, China
| | - Yang Liu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Bing Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Guirong Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518120, China
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2
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Cloonan K, Rizzato AR, Ferguson L, Hillier NK. Detection of heliothine sex pheromone components in the Australian budworm moth, Helicoverpa punctigera: electrophysiology, neuroanatomy, and behavior. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2020; 206:939-950. [PMID: 33098446 DOI: 10.1007/s00359-020-01450-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 10/01/2020] [Accepted: 10/09/2020] [Indexed: 11/24/2022]
Abstract
This study examined electrophysiological responses of the Australian budworm moth Helicoverpa punctigera, to heliothine sex pheromone components, via single sensillum recordings (SSR), and examined male neuroanatomy using confocal microscopy and 3D imaging tools. We found that male H. punctigera have three distinct regions of the macroglomerular complex (MGC) in the antennal lobe. Male antennae have only two functional types of sensilla trichoidea (A and C) and type A sensilla contain an olfactory sensory neuron (OSN) that responds to the major sex pheromone component (Z)-11-hexadecenal (Z11-16:Ald) with axons projecting to the cumulus of the macroglomerular complex (MGC) in the antennal lobe. Type C sensilla contained large-spiking receptor neurons which responded primarily to (Z)-9-tetradecenal (Z9-14:Ald) and to a lesser degree to (Z)-11-hexadecenol (Z11-16:OH). These were co-compartmentalized with small-spiking receptor neurons in type C sensilla which responded strongly to Z9-14:Ald and (Z)-9-hexadecenal (Z9-16:Ald), and to a lesser degree to (Z)-11-hexadecenyl acetate (Z11-16:OAc) and Z11-16:OH. Axons from the two co-localized neurons in Type C sensilla projected to the two small MGC units, the dorsomedial anterior and dorsomedial posterior, respectively. In wind tunnel assays, the addition of Z9-16:Ald to an otherwise attractive blend completely shut down male H. punctigera upwind flight.
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Affiliation(s)
- Kevin Cloonan
- Department of Biology, Acadia University, Wolfville, NS, B4P 2R6, Canada. .,Kevin Cloonan, Trécé Inc, PO Box 129, Adair, OK, 74330, USA.
| | - A Rebecca Rizzato
- Kentville Research and Development Centre, Agriculture and Agri-Food Canada, Kentville, NS, Canada
| | - Laura Ferguson
- Department of Biology, Acadia University, Wolfville, NS, B4P 2R6, Canada
| | - N Kirk Hillier
- Department of Biology, Acadia University, Wolfville, NS, B4P 2R6, Canada
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3
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Xu M, Dong JF, Wu H, Zhao XC, Huang LQ, Wang CZ. The Inheritance of the Pheromone Sensory System in Two Helicoverpa Species: Dominance of H. armigera and Possible Introgression from H. assulta. Front Cell Neurosci 2017; 10:302. [PMID: 28119570 PMCID: PMC5222888 DOI: 10.3389/fncel.2016.00302] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2016] [Accepted: 12/20/2016] [Indexed: 11/13/2022] Open
Abstract
Hybridization of sympatric closely related species may sometimes lead to introgression and speciation. The sister species Helicoverpa armigera and Helicoverpa assulta both use (Z)-11-hexadecenal and (Z)-9-hexadecenal as sex pheromone components but in reversed ratios. Female H. armigera and male H. assulta could hybridize and produce fertile male hybrids, which can then backcross with females of the two parent species to get backcross lines in the laboratory. In this study, we compared the olfactory responses to pheromone compounds in the periphery and in the antennal lobes (ALs) of males of the two species, as well as of their hybrids and backcrosses. Single-sensillum recordings were carried out to explore characteristics of male-specific sensilla on the antennae, and in vivo calcium imaging combined with digital 3D-reconstruction was used to describe what happens in the macroglomerular complex (MGC) of the AL. The results show that the population ratio of the two male-specific types of olfactory sensory neurons responding to two sex pheromone components are controlled by a major gene, and that the allele of H. armigera is dominant. Consistently, the study of the representative areas activated by sex pheromone components in the ALs further support the dominance of H. armigera. However, the topological structure of the MGC in the hybrid was similar but not identical to that in H. armigera. All subtypes of male-specific sensilla identified in the two species were found in the male hybrids and backcrosses. Moreover, two new subtypes with broader response spectra (the expanded A subtype and the expanded C subtype) emerged in the hybrids. Based on the inheritance pattern of the pheromone sensory system, we predict that when hybridization of female H. armigera and male H. assulta occurs in the field, male hybrids would readily backcross with female H. armigera, and introgression might occur from H. assulta into H. armigera through repeated backcrossing.
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Affiliation(s)
- Meng Xu
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of SciencesBeijing, China; College of Life Sciences, University of Chinese Academy of SciencesBeijing, China
| | - Jun-Feng Dong
- College of Forestry, Henan University of Science and Technology Luoyang, China
| | - Han Wu
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences Beijing, China
| | - Xin-Cheng Zhao
- Department of Entomology, College of Plant Protection, Henan Agricultural University Zhengzhou, China
| | - Ling-Qiao Huang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences Beijing, China
| | - Chen-Zhu Wang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of SciencesBeijing, China; College of Life Sciences, University of Chinese Academy of SciencesBeijing, China
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4
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Lee SG, Poole K, Linn CE, Vickers NJ. Transplant Antennae and Host Brain Interact to Shape Odor Perceptual Space in Male Moths. PLoS One 2016; 11:e0147906. [PMID: 26816291 PMCID: PMC4729490 DOI: 10.1371/journal.pone.0147906] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 01/07/2016] [Indexed: 11/30/2022] Open
Abstract
Behavioral responses to odors rely first upon their accurate detection by peripheral sensory organs followed by subsequent processing within the brain’s olfactory system and higher centers. These processes allow the animal to form a unified impression of the odor environment and recognize combinations of odorants as single entities. To investigate how interactions between peripheral and central olfactory pathways shape odor perception, we transplanted antennal imaginal discs between larval males of two species of moth Heliothis virescens and Heliothis subflexa that utilize distinct pheromone blends. During metamorphic development olfactory receptor neurons originating from transplanted discs formed connections with host brain neurons within olfactory glomeruli of the adult antennal lobe. The normal antennal receptor repertoire exhibited by males of each species reflects the differences in the pheromone blends that these species employ. Behavioral assays of adult transplant males revealed high response levels to two odor blends that were dissimilar from those that attract normal males of either species. Neurophysiological analyses of peripheral receptor neurons and central olfactory neurons revealed that these behavioral responses were a result of: 1. the specificity of H. virescens donor olfactory receptor neurons for odorants unique to the donor pheromone blend and, 2. central odor recognition by the H. subflexa host brain, which typically requires peripheral receptor input across 3 distinct odor channels in order to elicit behavioral responses.
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Affiliation(s)
- Seong-Gyu Lee
- Dept. of Biology, University of Utah, Salt Lake City, UT 84112, United States of America
| | - Kathy Poole
- Dept. of Entomology, Cornell University, Geneva, NY 14456, United States of America
| | - Charles E. Linn
- Dept. of Entomology, Cornell University, Geneva, NY 14456, United States of America
| | - Neil J. Vickers
- Dept. of Biology, University of Utah, Salt Lake City, UT 84112, United States of America
- * E-mail:
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Abstract
Moth sexual pheromones are widely studied as a fine-tuned system of intraspecific sexual communication that reinforces interspecific reproductive isolation. However, their evolution poses a dilemma: How can the female pheromone and male preference simultaneously change to create a new pattern of species-specific attraction? Solving this puzzle requires us to identify the genes underlying intraspecific variation in signals and responses and to understand the evolutionary mechanisms responsible for their interspecific divergence. Candidate gene approaches and functional analyses have yielded insights into large families of biosynthetic enzymes and pheromone receptors, although the factors controlling their expression remain largely unexplored. Intra- and interspecific crosses have provided tantalizing evidence of regulatory genes, although, to date, mapping resolution has been insufficient to identify them. Recent advances in high-throughput genome and transcriptome sequencing, together with established techniques, have great potential to help scientists identify the specific genetic changes underlying divergence and resolve the mystery of how moth sexual communication systems evolve.
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Affiliation(s)
- Astrid T Groot
- Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, 1090 GE Amsterdam, The Netherlands;
- Department of Entomology, Max Planck Institute for Chemical Ecology, 07745 Jena, Germany;
| | - Teun Dekker
- Department of Plant Protection Biology, Swedish University of Agricultural Sciences, SE-230 53 Alnarp, Sweden;
| | - David G Heckel
- Department of Entomology, Max Planck Institute for Chemical Ecology, 07745 Jena, Germany;
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Noh S, Henry CS. Speciation is not necessarily easier in species with sexually monomorphic mating signals. J Evol Biol 2015; 28:1925-39. [PMID: 26230311 DOI: 10.1111/jeb.12707] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 07/27/2015] [Indexed: 11/28/2022]
Abstract
Should we have different expectations regarding the likelihood and pace of speciation by sexual selection when considering species with sexually monomorphic mating signals? Two conditions that can facilitate rapid species divergence are Felsenstein's one-allele mechanism and a genetic architecture that includes a genetic association between signal and preference loci. In sexually monomorphic species, the former can manifest in the form of mate choice based on phenotype matching. The latter can be promoted by selection acting upon genetic loci for divergent signals and preferences expressed simultaneously in each individual, rather than acting separately on signal loci in males and preference loci in females. Both sexes in the Chrysoperla carnea group of green lacewings (Insecta, Neuroptera, Chrysopidae) produce sexually monomorphic species-specific mating signals. We hybridized the two species C. agilis and C. carnea to test for evidence of these speciation-facilitating conditions. Hybrid signals were more complex than the parents and we observed a dominant influence of C. carnea. We found a dominant influence of C. agilis on preferences in the form of hybrid discrimination against C. carnea. Preferences in hybrids followed patterns predicting preference loci that determine mate choice rather than a one-allele mechanism. The genetic association between signal and preference we detected in the segregating hybrid crosses indicates that speciation in these species with sexually monomorphic mating signals can have occurred rapidly. However, we need additional evidence to determine whether such genetic associations form more readily in sexually monomorphic species compared to dimorphic species and consequently facilitate speciation.
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Affiliation(s)
- S Noh
- Department of Biology, Washington University in St. Louis, St. Louis, MO, USA
| | - C S Henry
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT, USA
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7
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Berg BG, Zhao XC, Wang G. Processing of Pheromone Information in Related Species of Heliothine Moths. INSECTS 2014; 5:742-61. [PMID: 26462937 PMCID: PMC4592608 DOI: 10.3390/insects5040742] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Revised: 09/22/2014] [Accepted: 09/24/2014] [Indexed: 11/16/2022]
Abstract
In heliothine moths, the male-specific olfactory system is activated by a few odor molecules, each of which is associated with an easily identifiable glomerulus in the primary olfactory center of the brain. This arrangement is linked to two well-defined behavioral responses, one ensuring attraction and mating behavior by carrying information about pheromones released by conspecific females and the other inhibition of attraction via signal information emitted from heterospecifics. The chance of comparing the characteristic properties of pheromone receptor proteins, male-specific sensory neurons and macroglomerular complex (MGC)-units in closely-related species is especially intriguing. Here, we review studies on the male-specific olfactory system of heliothine moths with particular emphasis on five closely related species, i.e., Heliothis virescens, Heliothis subflexa, Helicoverpa zea, Helicoverpa assulta and Helicoverpa armigera.
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Affiliation(s)
- Bente G Berg
- Department of Psychology, Norwegian University of Science and Technology, Trondheim 7489, Norway.
| | - Xin-Cheng Zhao
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou 450002, China.
| | - Guirong Wang
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
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Hillier NK, Vickers NJ. Hairpencil volatiles influence interspecific courtship and mating between two related moth species. J Chem Ecol 2011; 37:1127-36. [PMID: 21948202 DOI: 10.1007/s10886-011-0017-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Revised: 08/15/2011] [Accepted: 09/07/2011] [Indexed: 11/27/2022]
Abstract
Reproductive isolation between sympatric, closely related species can be accomplished through a variety of pre-zygotic isolating mechanisms, including courtship-signaling behavior that involves pheromones. In the moths Heliothis virescens and H. subflexa, males display abdominal hairpencils (HP), which release volatile chemicals during courtship. In this study, we demonstrated that HP volatiles released by male H. subflexa function to improve mating success with conspecific females. Interspecific mating experiments were conducted to determine any influence of HP volatiles on species isolation. Female H. virescens and H. subflexa were observed during courtship with males of the other species, following either sham-operation or ablation of HPs, both with and without concurrent presentation of HP volatiles. Mating success was improved by co-presentation of HP extract from males of the same species during courtship. Ablation of HPs improved mating between H. subflexa females and H. virescens males. During interspecific matings, male H. virescens attempted copulation less frequently in the presence of H. virescens HP extract, though H. subflexa males were not affected by the presence of H. subflexa HP extract. This suggests that HP volatiles produced by males of each species may inhibit mating between species through effects on males (H. virescens) and females (H. subflexa).
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9
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Kárpáti Z, Olsson S, Hansson BS, Dekker T. Inheritance of central neuroanatomy and physiology related to pheromone preference in the male European corn borer. BMC Evol Biol 2010; 10:286. [PMID: 20846426 PMCID: PMC2949874 DOI: 10.1186/1471-2148-10-286] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Accepted: 09/16/2010] [Indexed: 11/21/2022] Open
Abstract
Background The European corn borer (ECB), Ostrinia nubilalis, is a textbook example of pheromone polymorphism. Males of the two strains (Z and E) prefer opposite ratios of the two pheromone components, Z11- and E11-tetradecenyl acetate, with a sex-linked factor underlying this difference in preference. The male antennal lobes of the two strains contain a pheromone sensitive macroglomerular complex (MGC) that is identical in morphology, but reversed in functional topology. However, hybrids prefer intermediate ratios. How a topological arrangement of two glomeruli can accommodate for an intermediate preference was unclear. Therefore we studied the neurophysiology of hybrids and paternal backcrosses to see which factors correlated with male behavior. Results Projection neuron (PN) recordings and stainings in hybrids and backcrosses show a dominance of the E-type MGC topology, notwithstanding their intermediate preference. Apparently, the topological arrangement of glomeruli does not directly dictate preference. However, two other factors did correlated very well with preference. First, volumetric measurements of MGC glomeruli demonstrate that, whereas in the parental strains the medial MGC glomerulus is more than 2 times larger than the lateral, in hybrids they are intermediate between the parents, i.e. equally sized. Paternal backcrosses showed that the volume ratio is sex-linked and co-dominant. Second, we measured the summed potential difference of the antennae in response to pheromone stimulation using electroantennogram recordings (EAG). Z-strain antennae responded 2.5 times stronger to Z11 than to E11-14:OAc, whereas in E-strain antennae the ratio was approximately equal. Hybrid responses were intermediate to the parents, and also here the antennal response of the paternal backcrosses followed a pattern similar to the behavioral phenotype. We found no differences in frequency and types of projection and local interneurons encountered between the two strains and their hybrids. Conclusions Male pheromone preference in the ECB strains serves as a strong prezygotic reproductive isolation mechanism, and has contributed to population divergence in the field. Our results demonstrate that male pheromone preference is not directly affected by the topological arrangement of olfactory glomeruli itself, but that male preference may instead be mediated by an antennal factor, which causes the MGC glomeruli to be differentially sized. We postulate that this factor affects readout of blend information from the MGC. The results are an illustration of how pheromone preference may be 'spelled out' in the ALs, and how evolution may modulate this.
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Affiliation(s)
- Zsolt Kárpáti
- Division of Chemical Ecology, Swedish University of Agricultural Sciences, PO Box 44, Sweden
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10
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Groot AT, Estock ML, Horovitz JL, Hamilton J, Santangelo RG, Schal C, Gould F. QTL analysis of sex pheromone blend differences between two closely related moths: Insights into divergence in biosynthetic pathways. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2009; 39:568-577. [PMID: 19477278 DOI: 10.1016/j.ibmb.2009.05.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2009] [Revised: 05/10/2009] [Accepted: 05/14/2009] [Indexed: 05/27/2023]
Abstract
To understand the evolution of premating signals in moths, it is important to know the genetic basis of these signals. We conducted Quantitative Trait Locus (QTL) analysis by hybridizing two noctuid moth species, Heliothis virescens (Hv) and Heliothis subflexa (Hs), and backcrossing the F(1) females to males of both parental species. One of these backcrosses (F(1) x Hs) was a biological replicate of our previous study (Sheck et al., 2006) and served to test the robustness of our previous findings. The backcross to Hv was designed to reveal QTL with recessive inheritance of the Hv character state. This study confirms previously discovered QTL, but also reports new QTL. Most importantly, we found relatively large QTL affecting Z9-16:Ald, the critical sex pheromone component of Hs. For Z9-14:Ald, the critical sex pheromone component of Hv, as well as for the minor pheromone compound 14:Ald, we found QTL in which the change in pheromone ratio was opposite-to-expected. Linking QTL to the biosynthetic pathways of the pheromone compounds of Hv and Hs implicates several candidate genes in the divergence of these premating signals, the most important of which are acetyl transferase, one or more desaturase(s), and a fatty acyl reductase or alcohol oxidase.
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Affiliation(s)
- Astrid T Groot
- Department of Entomology and W. M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, NC 27695-1713, USA.
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11
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Olsson SB, Linn CE, Feder JL, Michel A, Dambroski HR, Berlocher SH, Roelofs WL. Comparing peripheral olfactory coding with host preference in the rhagoletis species complex. Chem Senses 2008; 34:37-48. [PMID: 18791185 DOI: 10.1093/chemse/bjn053] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Recent studies have shown that flies from sympatric populations of Rhagoletis pomonella infesting hawthorn, apple, and flowering dogwood fruit can distinguish among unique volatile blends identified from each host. Analysis of peripheral chemoreception in Rhagoletis flies suggests that changes in receptor specificity and/or receptor neuron sensitivity could impact olfactory preference among the host populations and their hybrids. In an attempt to validate these claims, we have combined flight tunnel analyses and single sensillum electrophysiology in F(2) and backcross hybrids displaying a variety of behavioral phenotypes. Results show that differences in peripheral chemoreception among second-generation adults do not provide a direct correlation between peripheral coding and olfactory behavior. We conclude that either the plasticity of the central nervous system in Rhagoletis can compensate for significant alterations in peripheral coding or that peripheral changes present subtle effects on behavior not easily detectable with current techniques. The results of this study imply that the basis for olfactory behavior in Rhagoletis has a complicated genetic and neuronal basis, even for populations with a recent divergence in preference.
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Affiliation(s)
- Shannon B Olsson
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans Knöll, Jena, Germany.
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12
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Domingue MJ, Musto CJ, Linn CE, Roelofs WL, Baker TC. Olfactory neuron responsiveness and pheromone blend preference in hybrids between Ostrinia furnacalis and Ostrinia nubilalis (Lepidoptera: Crambidae). JOURNAL OF INSECT PHYSIOLOGY 2008; 54:1261-1270. [PMID: 18634788 DOI: 10.1016/j.jinsphys.2008.06.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2008] [Revised: 06/15/2008] [Accepted: 06/18/2008] [Indexed: 05/26/2023]
Abstract
The olfactory receptor neuron (ORN) and behavioral responses of hybrids between the Asian corn borer (ACB), Ostrinia furnacalis, and the E-strain European corn borer (ECB(E)), Ostrinia nubilalis were examined and compared to the parental populations. In hybrids and both parents, the large-spike-size ORN was capable of responding to all four pheromone components of ACB and ECB, despite differences in which compounds elicited the greatest spike frequency in each population. There was a small-spiking ORN more narrowly tuned to the minor pheromone components in both ACB and ECB(E). In hybrids the homologous small-spiking ORN was tuned primarily to the ECB(E) minor pheromone component, with some responsiveness to the ACB minor component. Both species and all the hybrids had an intermediate spike-size ORN tuned primarily to their common behavioral antagonist. Dominance of responsiveness to the ECB(E) versus the ACB minor pheromone component on the small-spiking ORN may explain the greater tendency of hybrids to fly upwind to the ECB(E) pheromone blend than the ACB blend. This finding points toward a distinct evolutionary role for this ORN in allowing a pheromone shift.
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Affiliation(s)
- Michael J Domingue
- Department of Entomology, Chemical Ecology Laboratory, Penn State University, University Park, PA 16802, USA.
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13
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Odor Detection in Insects: Volatile Codes. J Chem Ecol 2008; 34:882-97. [DOI: 10.1007/s10886-008-9485-4] [Citation(s) in RCA: 224] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2008] [Revised: 04/23/2008] [Accepted: 04/28/2008] [Indexed: 10/22/2022]
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14
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Balanced olfactory antagonism as a concept for understanding evolutionary shifts in moth sex pheromone blends. J Chem Ecol 2008; 34:971-81. [PMID: 18452043 DOI: 10.1007/s10886-008-9468-5] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2007] [Revised: 03/21/2008] [Accepted: 03/24/2008] [Indexed: 10/22/2022]
Abstract
In the sex pheromone communication systems of moths, both heterospecific sex pheromone components and individual conspecific pheromone components may act as behavioral antagonists when they are emitted at excessive rates and ratios. In such cases, the resulting blend composition does not comprise the sex pheromone of a given species. That is, unless these compounds are emitted at optimal rates and ratios with other compounds, they act as behavioral antagonists. Thus, the array of blend compositions that are attractive to males is centered around the characterized female-produced sex pheromone blend of a species. I suggest here that the resulting optimal attraction of males to a sex pheromone is the result of olfactory antagonistic balance, compared to the would-be olfactory antagonistic imbalance imparted by behaviorally active compounds when they are emitted individually or in other off-ratio blends. Such balanced olfactory antagonism might be produced in any number of ways in olfactory pathways, one of which would be mutual, gamma-aminobutyric-acid-related disinhibition by local interneurons in neighboring glomeruli that receive excitatory inputs from pheromone-stimulated olfactory receptor neurons. Such mutual disinhibition would facilitate greater excitatory transmission to higher centers by projection interneurons arborizing in those glomeruli. I propose that in studies of moth sex pheromone olfaction, we should no longer artificially compartmentalize the olfactory effects of heterospecific behavioral antagonists into a special category distinct from olfaction involving conspecific sex pheromone components. Indeed, continuing to impose such a delineation among these compounds may retard advances in understanding how moth olfactory systems can evolve to allow males to exhibit correct behavioral responses (that is, attraction) to novel sex-pheromone-related compositions emitted by females.
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15
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Symonds MRE, Elgar MA. The evolution of pheromone diversity. Trends Ecol Evol 2008; 23:220-8. [PMID: 18308422 DOI: 10.1016/j.tree.2007.11.009] [Citation(s) in RCA: 230] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2007] [Revised: 11/07/2007] [Accepted: 11/08/2007] [Indexed: 10/22/2022]
Abstract
Pheromones are chemical signals whose composition varies enormously between species. Despite pheromones being a nearly ubiquitous form of communication, particularly among insects, our understanding of how this diversity has arisen, and the processes driving the evolution of pheromones, is less developed than that for visual and auditory signals. Studies of phylogeny, genetics and ecological processes are providing new insights into the patterns, mechanisms and drivers of pheromone evolution, and there is a wealth of information now available for analysis. Future research could profitably use these data by employing phylogenetic comparative techniques to identify ecological correlates of pheromone composition. Genetic analyses are also needed to gain a clearer picture of how changes in receivers are associated with changes in the signal.
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Domingue MJ, Musto CJ, Linn CE, Roelofs WL, Baker TC. Altered olfactory receptor neuron responsiveness in rare Ostrinia nubilalis males attracted to the O. furnacalis pheromone blend. JOURNAL OF INSECT PHYSIOLOGY 2007; 53:1063-71. [PMID: 17624366 DOI: 10.1016/j.jinsphys.2007.05.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2007] [Revised: 05/30/2007] [Accepted: 05/31/2007] [Indexed: 05/16/2023]
Abstract
Three percent of E-strain Ostrinia nubilalis males fly upwind in response to the Ostrinia furnacalis pheromone blend [a 40:60 ratio of (E)-12-tetradecenyl acetate to (Z)-12-tetradecenyl acetate (E12-14:OAc to Z12-14:OAc)], in addition to their own pheromone blend [a 99:1 ratio of (E)-11-tetradecenyl acetate to (Z)-11-tetradecenyl acetate) (E11-14:OAc to Z11-14:OAc)]. We assessed the olfactory receptor neuron (ORN) responses of these behaviorally "rare" males versus those of normal males. For the three ORNs housed within each sensillum, we tested responsiveness to Z12-14:OAc, E12-14:OAc, Z11-14:OAc, E11-14:OAc, and the behavioral antagonist (Z)-9-tetradecenyl acetate (Z9-14:OAc). Z11-14:OAc, E11-14:OAc, and Z9-14:OAc stimulated ORNs exhibiting distinct small, large, and medium spike sizes, respectively. For rare and normal males, both Z12-14:OAc and E12-14:OAc usually elicited responses from the largest-spiking ORN. In many ORNs of normal males, Z12-14:OAc or E12-14:OAc stimulated the smaller-spiking ORN that is responsive to Z11-14:OAc. In rare males, detectable ORN responses from the smaller-spiking ORN in response to Z12- and E12-14:OAc were virtually non-existent. These differences in ORN tuning in rare males will tend to create an ORN firing ratio between the large- and small-spiking ORNs in response to the O. furnacalis blend that is similar to that elicited by the O. nubilalis blend.
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Affiliation(s)
- Michael J Domingue
- Center for Chemical Ecology, Department of Entomology, Chemical Ecology Laboratory, Penn State University, University Park, PA 16802, USA.
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Vickers NJ. Inheritance of olfactory preferences III. Processing of pheromonal signals in the antennal lobe of Heliothis subflexa x Heliothis virescens hybrid male moths. BRAIN, BEHAVIOR AND EVOLUTION 2006; 68:90-108. [PMID: 16707862 DOI: 10.1159/000093376] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2005] [Accepted: 09/01/2005] [Indexed: 11/19/2022]
Abstract
Pheromone-responsive olfactory interneurons were studied to determine the extent to which their physiological and morphological properties complemented the behavior and peripheral olfactory neurobiology observed in hybrid male moths created by interbreeding two species of heliothine moth, Heliothis virescens and Heliothis subflexa. Complete recordings were made from a total of 33 neurons, and 16 projection neurons (PNs) were subsequently stained with a fluorescent dye. Stained PNs tuned to pheromonal odorants had dendritic arborizations restricted to one of four olfactory glomeruli that together constituted the macroglomerular complex (MGC). As in parental males, PNs tuned to (Z)-11-hexadecenal always had an arbor in the cumulus, the largest of the MGC glomeruli. Previous neurophysiological investigations revealed that PNs with dendritic arbors restricted to the dorso-medial glomerulus (DM) of the MGC responded specifically to either (Z)-9-tetradecenal (Z9-14:Ald; H. virescens males) or (Z)-9-hexadecenal (Z9-16:Ald; H. subflexa males). Hybrid males, which responded equally well in wind tunnel tests to blends containing either Z9-14:Ald or Z9-16:Ald, had DM PNs that responded to both odorants. PNs specific for a third compound, (Z)-11-hexadecenol, required by hybrid males for behavioral activity were localized to the antero-medial MGC glomerulus (AM). Thus, neuronal activity across the cumulus, DM and AM glomeruli represented an attractive blend in hybrid males. Neurons tuned to (Z)-11-hexadecenyl acetate and Z9-14:Ald were restricted to a fourth, ventro-medial glomerulus. The across-glomerular pattern of activity associated with attractive pheromone blends was most similar to that of H. subflexa males, signifying a dominant effect of H. subflexa genes. These results indicate that the behavioral phenotype of hybrid males can be linked to underlying central olfactory characteristics.
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Affiliation(s)
- Neil J Vickers
- Department of Biology, University of Utah, Salt Lake City, Utah 84112, USA.
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Vickers NJ. Inheritance of olfactory preferences I. Pheromone-mediated behavioral responses of Heliothis subflexa x Heliothis virescens hybrid male moths. BRAIN, BEHAVIOR AND EVOLUTION 2006; 68:63-74. [PMID: 16707860 DOI: 10.1159/000093374] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2005] [Accepted: 09/01/2005] [Indexed: 11/19/2022]
Abstract
Shifts in male preference for qualitatively different pheromone blends appear to have played a fundamental role in the divergence of olfactory communication and evolution of moth species. As an initial step in documenting the genetic complexity underlying such shifts, we characterized the behavioral responses of hybrid male moths created by mating two heliothine moth species, Heliothis subflexa and Heliothis virescens. Between 67 and 96% of hybrid males flew upwind and contacted the pheromone source when presented with a blend consisting of (Z)-11-hexadecenal (Z11-16:Ald), (Z)-9-hexadecenal (Z9-16:Ald), and (Z)-11-hexadecenol (Z11-16:OH) in a 1:0.5:0.1 ratio that has previously been shown to be attractive to H. subflexa males. In addition, an H. virescens blend of Z11-16:Ald and (Z)-9-tetradecenal (Z9-14:Ald) enhanced by the addition of Z11-16:OH (in a 1:0.05:0.1 mixture) was attractive to hybrid males (26-64% source contact), but significantly fewer males reached the odor source compared to the blend containing Z9-16:Ald. A blend in which the dosage of Z9-14:Ald was doubled, however, was equally attractive (75-77% source contact) as the Z9-16:Ald-containing blend. Consecutive presentation of two blends revealed that individual hybrid males responded equally well to blends containing either Z9-14:Ald or Z9-16:Ald. Together these results suggest that in addition to Z11-16:Ald, hybrid males: (1) required either Z9-16:Ald (likeH. subflexamales) or Z9-14:Ald (like H. virescens males); (2) required the presence of Z11-16:OH (H. subflexa dominant); (3) were not adversely affected by the presence of Z11-16:Ac (H. subflexa dominant). The behavioral response phenotype of hybrid males was therefore influenced by genetic factors inherited from both parental species.
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Affiliation(s)
- Neil J Vickers
- Department of Biology, University of Utah, Salt Lake City, Utah 84112, USA.
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