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Hayes AM, Worthington AM, Lavine M, Lavine L. Phenotypically plastic responses to environmental variation are more complex than life history theory predicts. Evolution 2024; 78:1486-1498. [PMID: 38761110 DOI: 10.1093/evolut/qpae077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 04/01/2024] [Accepted: 05/16/2024] [Indexed: 05/20/2024]
Abstract
For insects that exhibit wing polyphenic development, abiotic and biotic signals dictate the adult wing morphology of the insect in an adaptive manner such that in stressful environments the formation of a flight-capable morph is favored and in low-stress environments, a flightless morph is favored. While there is a relatively large amount known about the environmental cues that dictate morph formation in wing polyphenic hemipterans like planthoppers and aphids, whether those cues dictate the same morphs in non-hemipteran (i.e., cricket) wing polyphenic species has not been explicitly investigated. To experimentally test the generality of environmental cue determination of wing polyphenism across taxa with diverse life histories, in this study, we tested the importance of food quantity, parasitic infection, and tactile cues on wing morph determination in the wing polyphenic sand field cricket, Gryllus firmus. Our results also show that certain stress cues, such as severe diet quantity limitation and parasitic infection, actually led to an increase in the production of flightless morph. Based on these findings, our results suggest that physiological and genetic constraints are important to an organism's ability to respond to environmental variation in an adaptive manner beyond simple life history trade-offs.
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Affiliation(s)
- Abigail M Hayes
- Department of Entomology, Washington State University, Pullman, WA, United States
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, Mansfield, CT, United States
| | - Amy M Worthington
- Department of Biology, Creighton University, Omaha, NE, United States
| | - Mark Lavine
- Department of Entomology, Washington State University, Pullman, WA, United States
| | - Laura Lavine
- Department of Entomology, Washington State University, Pullman, WA, United States
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Deem KD, Gregory LE, Liu X, Ziabari OS, Brisson JA. Evolution and molecular mechanisms of wing plasticity in aphids. CURRENT OPINION IN INSECT SCIENCE 2024; 61:101142. [PMID: 37979724 PMCID: PMC10843803 DOI: 10.1016/j.cois.2023.101142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 10/06/2023] [Accepted: 11/13/2023] [Indexed: 11/20/2023]
Abstract
Aphids present a fascinating example of phenotypic plasticity, in which a single genotype can produce dramatically different winged and wingless phenotypes that are specialized for dispersal versus reproduction, respectively. Recent work has examined many aspects of this plasticity, including its evolution, molecular control mechanisms, and genetic variation underlying the trait. In particular, exciting discoveries have been made about the signaling pathways that are responsible for controlling the production of winged versus wingless morphs, including ecdysone, dopamine, and insulin signaling, and about how specific genes such as REPTOR2 and vestigial are regulated to control winglessness. Future work will likely focus on the role of epigenetic mechanisms, as well as developing transgenic tools for more thoroughly dissecting the role of candidate plasticity-related genes.
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Affiliation(s)
- Kevin D Deem
- Department of Biology, University of Rochester, Rochester, NY 14627, USA
| | - Lauren E Gregory
- Department of Biology, University of Rochester, Rochester, NY 14627, USA
| | - Xiaomi Liu
- Department of Biology, University of Rochester, Rochester, NY 14627, USA
| | - Omid S Ziabari
- Department of Biology, University of Rochester, Rochester, NY 14627, USA
| | - Jennifer A Brisson
- Department of Biology, University of Rochester, Rochester, NY 14627, USA.
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Rozo-Lopez P, Parker BJ. Why do viruses make aphids winged? INSECT MOLECULAR BIOLOGY 2023; 32:575-582. [PMID: 37243432 DOI: 10.1111/imb.12860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 05/12/2023] [Indexed: 05/28/2023]
Abstract
Aphids are hosts to diverse viruses and are important vectors of plant pathogens. The spread of viruses is heavily influenced by aphid movement and behaviour. Consequently, wing plasticity (where individuals can be winged or wingless depending on environmental conditions) is an important factor in the spread of aphid-associated viruses. We review several fascinating systems where aphid-vectored plant viruses interact with aphid wing plasticity, both indirectly by manipulating plant physiology and directly through molecular interactions with plasticity pathways. We also cover recent examples where aphid-specific viruses and endogenous viral elements within aphid genomes influence wing formation. We discuss why unrelated viruses with different transmission modes have convergently evolved to manipulate wing formation in aphids and whether this is advantageous for both host and virus. We argue that interactions with viruses are likely shaping the evolution of wing plasticity within and across aphid species, and we discuss the potential importance of these findings for aphid biocontrol.
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Affiliation(s)
- Paula Rozo-Lopez
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - Benjamin J Parker
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
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Liu X, Brisson JA. Dopamine mediates the pea aphid wing plasticity. Biol Lett 2023; 19:20230024. [PMID: 37194256 PMCID: PMC10189302 DOI: 10.1098/rsbl.2023.0024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Accepted: 04/26/2023] [Indexed: 05/18/2023] Open
Abstract
Many organisms exhibit phenotypic plasticity, in which developmental processes result in different phenotypes depending on their environmental context. Here we focus on the molecular mechanisms underlying that environmental response. Pea aphids (Acyrthosiphon pisum) exhibit a wing dimorphism, in which pea aphid mothers produce winged or wingless daughters when exposed to a crowded or low-density environment, respectively. We investigated the role of dopamine in mediating this wing plasticity, motivated by a previous study that found higher dopamine titres in wingless- versus winged-producing aphid mothers. In this study, we found that manipulating dopamine levels in aphid mothers affected the numbers of winged offspring they produced. Specifically, asexual female adults injected with a dopamine agonist produced a lower percentage of winged offspring, while asexual females injected with a dopamine antagonist produced a higher percentage of winged offspring, matching expectations based on the titre difference. We also found that genes involved in dopamine synthesis, degradation and signalling were not differentially expressed between wingless- and winged-producing aphids. This result indicates that titre regulation possibly happens in a non-transcriptional manner or that sampling of additional timepoints or tissues is necessary. Overall, our work emphasizes that dopamine is an important component of how organisms process information about their environments.
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Affiliation(s)
- Xiaomi Liu
- Department of Biology, University of Rochester, Rochester, NY 14610, USA
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Yuan E, Guo H, Chen W, Du B, Mi Y, Qi Z, Yuan Y, Zhu-Salzman K, Ge F, Sun Y. A novel gene REPTOR2 activates the autophagic degradation of wing disc in pea aphid. eLife 2023; 12:e83023. [PMID: 36943031 PMCID: PMC10030113 DOI: 10.7554/elife.83023] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 03/01/2023] [Indexed: 03/23/2023] Open
Abstract
Wing dimorphism in insects is an evolutionarily adaptive trait to maximize insect fitness under various environments, by which the population could be balanced between dispersing and reproduction. Most studies concern the regulatory mechanisms underlying the stimulation of wing morph in aphids, but relatively little research addresses the molecular basis of wing loss. Here, we found that, while developing normally in winged-destined pea aphids, the wing disc in wingless-destined aphids degenerated 30-hr postbirth and that this degeneration was due to autophagy rather than apoptosis. Activation of autophagy in first instar nymphs reduced the proportion of winged aphids, and suppression of autophagy increased the proportion. REPTOR2, associated with TOR signaling pathway, was identified by RNA-seq as a differentially expressed gene between the two morphs with higher expression in the thorax of wingless-destined aphids. Further genetic analysis indicated that REPTOR2 could be a novel gene derived from a gene duplication event that occurred exclusively in pea aphids on autosome A1 but translocated to the sex chromosome. Knockdown of REPTOR2 reduced autophagy in the wing disc and increased the proportion of winged aphids. In agreement with REPTOR's canonical negative regulatory role of TOR on autophagy, winged-destined aphids had higher TOR expression in the wing disc. Suppression of TOR activated autophagy of the wing disc and decreased the proportion of winged aphids, and vice versa. Co-suppression of TOR and REPTOR2 showed that dsREPTOR2 could mask the positive effect of dsTOR on autophagy, suggesting that REPTOR2 acted as a key regulator downstream of TOR in the signaling pathway. These results revealed that the TOR signaling pathway suppressed autophagic degradation of the wing disc in pea aphids by negatively regulating the expression of REPTOR2.
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Affiliation(s)
- Erliang Yuan
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of SciencesBeijingChina
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of ScienceBeijingChina
| | - Huijuan Guo
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of SciencesBeijingChina
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of ScienceBeijingChina
| | - Weiyao Chen
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of SciencesBeijingChina
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of ScienceBeijingChina
| | - Bingru Du
- School of Life Science, Hebei UniversityBaodingChina
| | - Yingjie Mi
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of SciencesBeijingChina
| | - Zhaorui Qi
- School of Life Science, Hebei UniversityBaodingChina
| | - Yiyang Yuan
- Institute of Plant Protection, Shandong Academy of Agriculture SciencesJinanChina
| | - Keyan Zhu-Salzman
- Department of Entomology, Texas A&M UniversityCollege StationUnited States
| | - Feng Ge
- Institute of Plant Protection, Shandong Academy of Agriculture SciencesJinanChina
| | - Yucheng Sun
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of SciencesBeijingChina
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of ScienceBeijingChina
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Forni G, Martelossi J, Valero P, Hennemann FH, Conle O, Luchetti A, Mantovani B. Macroevolutionary Analyses Provide New Evidence of Phasmid Wings Evolution as a Reversible Process. Syst Biol 2022; 71:1471-1486. [PMID: 35689634 DOI: 10.1093/sysbio/syac038] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 05/13/2022] [Accepted: 05/24/2022] [Indexed: 11/13/2022] Open
Abstract
The concept that complex ancestral traits can never be recovered after their loss is still widely accepted, despite phylogenetic and molecular approaches suggest instances where phenotypes may have been lost throughout the evolutionary history of a clade and subsequently reverted back in derived lineages. One of the first and most notable examples of such a process is wing evolution in phasmids; this polyneopteran order of insects, which comprises stick and leaf insects, has played a central role in initiating a long-standing debate on the topic. In this study, a novel and comprehensive time tree including over 300 Phasmatodea species is used as a framework for investigating wing evolutionary patterns in the clade. Despite accounting for several possible biases and sources of uncertainty, macroevolutionary analyses consistently revealed multiple reversals to winged states taking place after their loss, and reversibility is coupled with higher species diversification rates. Our findings support a loss of or reduction in wings that occurred in the lineage leading to the extant phasmid most recent common ancestor, and brachyptery is inferred to be an unstable state unless co-opted for nonaerodynamic adaptations. We also explored how different assumptions of wing reversals probability could impact their inference: we found that until reversals are assumed to be over 30 times more unlikely than losses, they are consistently inferred despite uncertainty in tree and model parameters. Our findings demonstrate that wing evolution is a reversible and dynamic process in phasmids and contribute to our understanding of complex trait evolution.
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Affiliation(s)
- Giobbe Forni
- Dip. Scienze Biologiche, Geologiche e Ambientali (BiGeA), University of Bologna, Italy
| | - Jacopo Martelossi
- Dip. Scienze Biologiche, Geologiche e Ambientali (BiGeA), University of Bologna, Italy
| | | | | | | | - Andrea Luchetti
- Dip. Scienze Biologiche, Geologiche e Ambientali (BiGeA), University of Bologna, Italy
| | - Barbara Mantovani
- Dip. Scienze Biologiche, Geologiche e Ambientali (BiGeA), University of Bologna, Italy
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Male-Biased microRNA Discovery in the Pea Aphid. INSECTS 2021; 12:insects12060533. [PMID: 34201015 PMCID: PMC8228725 DOI: 10.3390/insects12060533] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 05/28/2021] [Accepted: 06/01/2021] [Indexed: 12/18/2022]
Abstract
Epigenetic mechanisms modulate gene expression levels during development, shaping how a single genome produces a diversity of phenotypes. Here, we begin to explore the epigenetic regulation of sexual dimorphism in pea aphids (Acyrthosiphon pisum) by focusing on microRNAs. Previous analyses of microRNAs in aphids have focused solely on females, so we performed deep sequencing of a sample containing early-stage males. We used this sample, plus samples from Genbank, to find 207 novel pea aphid microRNA coding loci. We localized microRNA loci to a chromosome-level assembly of the pea aphid genome and found that those on the X chromosome have lower overall expression compared to those on autosomes. We then identified a set of 19 putative male-biased microRNAs and found them enriched on the X chromosome. Finally, we performed protein-coding RNA-Seq of first instar female and male pea aphids to identify genes with lower expression in males. 10 of these genes were predicted targets of the 19 male-biased microRNAs. Our study provides the most complete set of microRNAs in the pea aphid to date and serves as foundational work for future studies on the epigenetic control of sexual dimorphism.
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