Latent gene network expression underlies partial re-evolution of a polyphenic trait in the worker caste of ants
- Center for Evolutionary and Organismal Biology, Women’s Hospital, School of Medicine, Zhejiang University, China
- McGill University, Department of Biology, Canada
Figures
Figure 1
The presence and absence of ocelli in queens and workers across ants.
(A) Ocelli develop in the winged reproductive castes across species of Formicinae ants exemplified by C. floridanus, C. bicolor, P. bihamata, and D. gigas (white dashed circles). Ocelli in the worker caste of formicine ants (white dashed circles) are evolutionarily labile, showing no ocelli (C. floridanus), all three ocelli in all individuals of the worker caste (C. bicolor), or only one ocellus in only the soldiers (P. bihamata and D. gigas). (B) Schematic representation of the ocelli GRN in Drosophila melanogaster adapted from Figure 5A from Jean-Guillaume and Kumar, 2022. The genes investigated in this study are highlighted in orange. Arrowheads indicate activation, and bars indicate repression. Queens are scaled to 1 mm, and workers and soldiers are scaled according to the queen of each species. Asterisks indicate that C. floridanus was used for gene expression studies. Photos from Antweb (AntWeb, 2026).
Figure 2
Ancestral state reconstruction of ocelli reveals three well-supported reversions of ocelli in the worker caste in the tribe Camponotini.
Maximum clade credibility tree of formicine ants from Blaimer et al., 2015. Ancestral state reconstruction for the presence (blue-colored circles) and absence (red-colored circles) of ocelli based on stochastic character mapping. Each pie chart for the nodes represents the posterior probabilities, scaled by the weight of evidence for each model. Species used to analyze ocelli GRN expression are highlighted in gray, and the species that re-evolved one ocellus is indicated as partial re-evolution. Three tribes within the Formicinae are marked (Melophorini, Plagiolepidini, Lasiini, Myrmelachistini and Camponotini) by arrows.
Figure 3 with 1 supplement
Characterizing development of the eye-antenna imaginal disc in worker castes of C. floridanus using orthodenticle-1 (otd-1), distal-less (dll), and eyeless (ey) gene expression to mark the developing head capsule and ocelli, antenna, and eyes.
Fluorescent images in panels A, F, K, P, U represent the development of the entire eye-antenna imaginal disc marked with the nuclear stain DAPI across all four larval stages, where the head capsule region is labeled as ‘Hc’, the antennal region is labeled as ‘An,’ and the eye region is labeled as ‘Eye’. Panels B, G, L, Q, and V represent the development of the head capsule (Hc) marked by the genes orthodenticle-1 (otd-1 in magenta); panels C, H, M, R, and W represent the antennal region marked by distal-less (dll) in green color; and panels D, I, N, S, and X represent the eyes (Eye) is eyeless (ey) (yellow); (A–E) First instar, images are to scale (white bar in A). Note: the green or yellow staining outside of the structures highlighted by the white arrows in panels C, D, and E is background noise. (F–J) Second instar, images are to scale (white bar in F), (K–O) third instar, images are to scale (white bar in K), (P–T) fourth instar worker-destined larvae, images are to scale (white bar in P). (U–Y) Fourth instar soldier-destined larvae, images are to scale (white bar in U). Scale bars = 100 µm.
Figure 3—figure supplement 1
Simplified Gene tree based on maximum likelihood showing relationships between orthodenticle (otd) orthologs in D. melanogaster, Apis mellifera, Nasonia vitripennis, Tribolium castaneum, Acythosiphon pisum, and C. floridanus.
Branch values are bootstrap support (%). Colors: otd-2 (red), otd-1 (blue).
Figure 4
Latent expression of otd-1 and hh genes in the ocelli GRN in workers and soldiers of C. floridanus during the 4th larval instars.
Expression of orthodenticle-1 (otd-1) is yellow, and hedgehog (hh) is magenta. Early 4th instar; (A, B) males (C, D) soldiers and (E, F) workers. Late 4th instar: (A,’ B’) males (C’, D’) soldiers and (E’, F’) workers. Images are not to scale.
Figure 5
Latent expression of toy, eya, and so within the ocelli GRN in the developing workers and soldiers of C. floridanus.
Expression of toy (green), eya (yellow), and so (magenta). Early 4th instar; (A–C) males, (D–F) soldiers, and (G–I) workers. Late 4th larvae stage; (A’–C’) males, (D’–F’), soldiers, and (G’–I’). Images are not to scale.
Figure 6
Latent expression of the ocelli GRN in the eye-antennal disc in worker larvae of Polyrachis rastellata at 4th larval stages.
Expression of selected genes otd-1 (yellow), eya (yellow), and so (magenta) at early 4th instar larvae. Images are not to scale.
Figure 7
Development of rudimentary ocelli in worker and soldier pupae of C. floridanus.
(A) SEM showing ocelli development in males at mid-stages of pupal development. SEM showing development of rudimentary ocelli on (B–E) soldiers and (F–I) minor workers during early (day 6–7), mid (day 16–17), and late (19-20) pupal development. These ocelli rudiments disappear prior to adult stage (E–I).
Author response image 1
RNAi knockdowns in developing soldiers of Camponotus floridanus show a reduction of otd -1 expression in the brain, but no effect on otd -1 expression in the eye-antenna disc.
A. HCR revealing otd -1 expression in the brain B. qPCR of otd -1 expression after RNAi knockdown shows significantly reduced otd -1 expression in the brain, C. HCR revealing otd -1 expression in the eye-antenna disc D. qPCR of otd -1 expression after RNAi knockdown shows no significant affect on otd -1 expression in the eye-antenna disc.
Tables
Key resources table
| Reagent type (species) or resource | Designation | Source or reference | Identifiers | Additional information |
|---|---|---|---|---|
| Gene (Camponotus floridanus) | eyeless distal-less hedgehog eye absent sine oculis twin of eyeless orthodenticle | GenBank | XM_025414466 XM_025412727.1 XM_011262474.3 XM_011262474.3 XM_011252868.3 XM_011268499.3 XM_020028684.2 | |
| Commercial assay or kit | Hybridization Chain Reaction in situ hybridization probes | Molecular Instruments | ||
| Software, algorithm | R software Fiji Photoshop Illustrator Tracer Geneious MEGA 12 alpa |
Appendix 1—table 1
Model selection under maximum likelihood estimation implemented in phytools (Revell, 2024).
The results are ordered by decreasing Akaike Weights (w).
| Model | log(L) | d.f. | AIC | weight |
|---|---|---|---|---|
| Equal Rates | –41.808109 | 1 | 85.6162173 | 0.70944317 |
| Unequal Rates | –41.720603 | 2 | 87.441205 | 0.28485677 |
| Irreversible: Absence to Presence | –46.813104 | 1 | 95.6262081 | 0.00475637 |
| Irreversible: Presence to Absence | –48.430553 | 1 | 98.8611065 | 0.00094368 |
Appendix 1—table 2
Database with the references used in this study for presence and number of ocellus (1) and absence (0) of ocellus.
| Subfamily | Genus | Species | Ocelli Count | References |
|---|---|---|---|---|
| outgroup | Acanthoponera | minor | 0 | AntWeb.org |
| Formicinae | Acropyga | acutiventris | 0 | AntWeb.org |
| outgroup | Aneuretus | simoni | 0 | AntWeb.org |
| Formicinae | Anoplolepis | custodiens | 0 | AntWeb.org |
| Formicinae | Anoplolepis | gracilipes | 0 | AntWeb.org |
| Formicinae | Aphomomyrmex | afer | 3 | AntWeb.org |
| Formicinae | Bajcaridris | theryi | 3 | Santschi, 1936 |
| outgroup | Brachymyrmex | depilis | 0 | AntWeb.org |
| Formicinae | Calomyrmex | albertisi | 0 | AntWeb.org |
| Formicinae | Calomyrmex | laevissimus | 0 | AntWeb.org |
| Formicinae | Camponotus | floridanus | 0 | AntWeb.com |
| Formicinae | Camponotus | gibbinotus | 1 | AntWeb.org |
| Formicinae | Camponotus | hyatti | 0 | MacKay and Mackay, 2002 |
| Formicinae | Camponotus | maritimus | 0 | Ward, 2005 |
| Formicinae | Colobopsis | saundersi | 0 | AntWeb.org |
| Formicinae | Colobopsis | vitiensis | 0 | Mann, 1920 |
| Formicinae | Cataglyphis | cursor | 3 | AntWeb.org |
| outgroup | Cladomyrma | petalae | 0 | Agosti, 1991 |
| outgroup | Dolichoderus | pustulatus | 0 | AntWeb.org |
| Formicinae | Dinomyrmex | gigas | 1 | AntWeb.org |
| Formicinae | Echinopla | australis | 0 | AntWeb.org |
| Formicinae | Euprenolepis | procera | 0 | Lapolla, 2009 |
| Formicinae | Formica | moki | 3 | Cole, 1943 |
| Formicinae | Formica | neogagates | 3 | AntWeb.org |
| Formicinae | Gigantiops | destructor | 3 | Smith, 1858 |
| Formicinae | Iberoformica | subrufa | 3 | Antwiki- genus |
| Formicinae | Lasiophanes | atriventris | 3 | AntWeb.org |
| Formicinae | Lasius | californicus | 0 | AntWeb.org |
| Formicinae | Lasius | niger | 3 | AntWeb.org |
| Formicinae | Lepisiota | canescens | 3 | Sharaf et al., 2020 |
| outgroup | Manica | bradleyi | 0 | AntWeb.org |
| outgroup | Myrmecia | pyriformis | 3 | AntWeb.org |
| Formicinae | Myrmecocystus | flaviceps | 3 | AntWeb.org |
| Formicinae | Myrmecorhynchus | emeryi | 3 (soldiers and media, absent in minors) | Wheeler, 1917 |
| outgroup | Myrmelachista | flavocotea | 0 | AntWeb.org |
| Formicinae | Myrmoteras | iriodum | 3 | AntWeb.org |
| outgroup | Nothomyrmecia | macrops | 0 | AntWeb.org |
| Formicinae | Notoncus | capitatus | 3 | AntWeb.org |
| Formicinae | Notostigma | carazzii | 3 | AntWeb.org; Emery, 1911 |
| Formicinae | Nylanderia | dodo | 0 | Lapolla et al., 2011 |
| Formicinae | Nylanderia | hystrix | 3 | Kallal and LaPolla, 2012 |
| Formicinae | Oecophylla | longinoda | 0 | AntWeb.org |
| Formicinae | Oecophylla | smaragdina | 0 | Cole and Jones, 1948 |
| Formicinae | Opisthopsis | respiciens | 0 | AntWeb.org |
| Formicinae | Paraparatrechina | glabra | 3 | AntWeb.org |
| Formicinae | Paraparatrechina | oceanica | 0 | AntWeb.org |
| Formicinae | Paratrechina | antsingy | 3 | LaPolla and Fisher, 2014 |
| Formicinae | Paratrechina | longicornis | 3 | AntWeb.org |
| Formicinae | Paratrechina | zanjensis | 3 | LaPolla et al., 2013 |
| Formicinae | Petalomyrmex | phylax | 3 | Snelling, 1979 |
| Formicinae | Plagiolepis | alluaudi | 0 | AntWeb.org |
| Formicinae | Polyergus | breviceps | 3 | AntWeb.org; Smith, 1947 |
| Formicinae | Polyrhachis | decumbens | 0 | Kohout, 2006 |
| Formicinae | Prenolepis | emmae | 3 | AntWeb.org |
| Formicinae | Prenolepis | imparis | 0 | Williams and Lapolla, 2016 |
| Formicinae | Proformica | mongolica | 3 | AntWeb.org |
| Formicinae | Prolasius | convexus | 3 | McAreavey, 1957 |
| Formicinae | Pseudolasius | australis | 0 | Emery, 1925 |
| Formicinae | Pseudonotoncus | hirsutus | 3 | Shattuck and O’Reilly, 2013 |
| outgroup | Rhytidoponera | chalybaea | 0 | AntWeb.org |
| Formicinae | Rossomyrmex | anatolicus | 3 | AntWeb.org |
| Formicinae | Santschiella | kohli | 3 | Forel, 1893 |
| Formicinae | Teratomyrmex | greavesi | 3 | Shattuck and O’Reilly, 2013 |
| outgroup | Tetraponera | rufonigra | 3 | Ward, 2001 |
| Formicinae | Zatania | albimaculata | 3 | AntWeb.org |
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Latent gene network expression underlies partial re-evolution of a polyphenic trait in the worker caste of ants
eLife 15:RP110148.
https://doi.org/10.7554/eLife.110148.3
