The Wing

May 27, 2026 • 1848 to 1862, the Bates and Wallace Amazon expedition and the Linnean Society of London • 5 min read

Verified 12 claims · 6 searches · 1 pass

Split-frame editorial illustration. Left side: cool late-autumn London evening of Thursday 21 November 1861, interior of the Linnean Society meeting hall at Burlington House on Piccadilly. Henry Walter Bates at the painted-walnut speaker's lectern in dark wool frock coat with cream linen wing-collar, dark silk cravat, short dark hair, short dark beard and moustache, wire-rimmed reading spectacles, in three-quarter rear silhouette holding a hand-bound foolscap manuscript above the lectern. Beside the lectern, a painted-walnut display stand holds a small painted-cream-and-soft-amber Victorian cork-and-glass specimen case displaying pinned soft-orange-and-black Heliconius and Ithomiini butterfly specimens. Polished oak floorboards in the foreground with the painted-walnut backs of seated Linnean Fellows in Victorian formal evening dress visible in three-quarter rear silhouette. Painted-cream Linnean Society walls rise into soft warm amber chandelier-glow, with gilt-framed sepia portraits of past Linnean presidents on the back walls and a prominent gilt-framed portrait of Carl Linnaeus above the lectern. Painted-walnut bookshelves along the side walls hold leather-bound natural-history volumes. An ornate brass-and-crystal Victorian chandelier hangs above the lectern casting strong directional warm amber light. Tall narrow casement windows at the back are covered by heavy oxblood-red velvet curtains. Right side: clear cool morning of early May 2026, interior of the Lepidoptera genomics laboratory at the Wellcome Sanger Institute on the Wellcome Genome Campus near Hinxton in Cambridgeshire. A senior genomics researcher in modern cream cotton-and-poly laboratory coat over navy modern business shirt, short dark hair, dark spectacles, in three-quarter side silhouette leaning forward over a polished modern stainless-steel laboratory bench with a small painted-bronze hand-held magnifying lens. On the bench, a modern cream-and-glass specimen-tray holds three pinned soft-orange-and-black Heliconius and Ithomiini butterfly specimens beside a painted-soft-grey-and-cream Chetone moth specimen. A modern matte-black dissecting microscope sits at the upper-right. A modern flat-screen monitor at the upper-left of the bench shows a cool electric-cyan-and-soft-pink genomic-alignment plot with soft umber gene-track lines and painted-cool-amber labels for the ivory and optix genes. A younger postdoctoral researcher in modern cream laboratory coat at the far back-right of the bench holds a modern matte-black digital tablet in three-quarter rear silhouette. The painted-cream-and-soft-amber Sanger Institute laboratory walls rise into soft umber shadow at the upper edges. A modern hanging matte-black laboratory lamp casts a soft amber pool of light across the bench. A tall narrow modern frosted-glass window at the back wall opens onto a cool slate-blue Cambridgeshire May morning. The two halves share a single continuous warm amber chandelier-and-lamp horizon ribbon running edge to edge across the centre of the frame, joining the 1861 Linnean Society lecture hall on the left to the 2026 Sanger Institute laboratory on the right. The same soft-orange-and-black Heliconius butterfly specimens appear in a Victorian cork-and-glass specimen case on the left and on a modern stainless-steel specimen-tray on the right as the central visual continuity hook.

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The Echo

The April 1848 departure of Henry Walter Bates and Alfred Russel Wallace from Liverpool for the Amazon basin, Bates's eleven-year residence in the rainforest during which he shipped home approximately 14,712 specimens (8,000 new to science) via three separate vessels to insure against loss, his return in 1859, the 21 November 1861 reading of his Heliconidae paper before the Linnean Society of London, and the 1862 publication of the paper in the Transactions of the Linnean Society as the first published independent evidence for Darwinian natural selection beyond Darwin's own work. Charles Darwin called it 'one of the most remarkable and admirable papers I have ever read in my life.' (1848 to 1862, the Bates and Wallace Amazon expedition and the Linnean Society of London) ↔ On 2 May 2026 an international team led by the Wellcome Sanger Institute and the University of York published in PLOS Biology 'Genetic parallelism underpins convergent mimicry coloration in Lepidoptera across 120 million years of evolution.' Working from whole-genome sequencing of seven species of Heliconius and Ithomiini butterflies and a day-flying Chetone moth, the team showed that across 120 million years of independent evolution Lepidoptera have re-used the same two genes, ivory and optix, to produce convergent warning-colour patterns. The protein-coding sequences are conserved; the evolution sits in the regulatory switches. One moth species deploys the genes via a chromosomal inversion identical in orientation to one independently evolved by a butterfly lineage millions of years earlier. The space of viable genomic solutions to the Batesian-mimicry problem is small, and lineages 120 million years apart reach for the same tools. (Today)

The April morning Henry Walter Bates sailed out of Liverpool for the Amazon in 1848, he was twenty-three years old and had spent most of his life on the floor of a hosiery warehouse in Leicester. He was the second son of a literate, ambitious middle-class family with no money for university, and he had taught himself entomology by collecting beetles in the Charnwood Forest on his days off. He had met Alfred Russel Wallace, a year older, in 1844 when Wallace took a teaching post at the Leicester Collegiate School. The two read Charles Darwin's Journal of Researches together and decided that the natural place for two self-taught Victorian naturalists with no academic credentials was the rainforest. They would pay their way home by selling specimens to the British Museum, to private collectors, and through their London agent Samuel Stevens.

Wallace lasted four years in South America. On the return voyage of 1852 his ship caught fire in the middle of the Atlantic and the entire collection, the journals, the dried bird skins, the boxes of pinned insects, went down with the Helen. He went back to the field three years later, this time to the Malay Archipelago.

Bates stayed. He stayed eleven years. He shipped his specimens home in three separate consignments on three separate ships specifically because he had seen what had happened to Wallace. Every box arrived. By the time he came home in 1859, exhausted and malarial and unable for a long time to face being in a room with other people, he had sent fourteen thousand seven hundred and twelve species of insect, bird, fish, reptile, plant, and mammal back to England. Eight thousand of them were new to science.

The one he could not stop thinking about was a butterfly.

In the várzea flood-forest of the upper Solimões he had repeatedly netted, over hundreds of identifications, two butterflies that looked nearly identical: the same dramatic black-and-orange wing pattern, the same lazy flight, the same flat resting posture. When he laid them out on his collecting board and looked at the wing venation and the abdomen, however, they turned out to belong to completely unrelated families. One was a Heliconius. The other was an unrelated Dismorphia or Mechanitis. He found the same pattern of unrelated lookalikes repeated across dozens of species pairs across the Amazon basin. He noticed that one of each pair was always the chemically defended one, the one a hungry bird would learn from one taste never to touch again. The other was an imposter.

On 21 November 1861, having spent two years writing it up at his desk in Leicester, Bates read a paper before the Linnean Society of London titled "Contributions to an Insect Fauna of the Amazon Valley: Lepidoptera, Heliconidae." The paper appeared in the Transactions the following year. It argued that the unrelated species had converged on the same wing pattern because birds had selected for the convergence: any individual whose wing pattern happened to resemble the unpalatable model lived longer, reproduced more, and passed the resemblance on. It was Darwin's natural selection in action, and the first independent demonstration of it published by anyone other than Darwin or Wallace themselves. Darwin wrote to Bates that the paper was "one of the most remarkable and admirable papers I have ever read in my life." It is now the foundation of the field that bears Bates's name. Batesian mimicry.

What he could not explain, in 1861, was how. There was no Mendel yet. Gregor Mendel was, that month, growing pea plants at the abbey at Brünn but would not publish for another four years, and the paper would sit unread for thirty-five. There was no DNA, no gene, no notion that two completely unrelated lineages might share a deep machinery. Bates wrote that the mimic must have evolved the pattern by gradual modification of its own ancestral form under selection. He could not say more.

On 2 May 2026, in PLOS Biology, an international team led by the Wellcome Sanger Institute and the University of York published "Genetic parallelism underpins convergent mimicry coloration in Lepidoptera across 120 million years of evolution." Working from whole-genome sequencing of seven species of Heliconius and Ithomiini butterflies and a day-flying Chetone moth, populations Bates himself collected in the same Amazon basin in the 1850s, they showed that all of them, across 120 million years of independent evolution, produce their nearly-identical mimetic wing patterns by re-using exactly the same two genes. The genes are called ivory and optix. They are conserved across the entire lepidopteran order. The species themselves diverged before the dinosaurs were extinct, well before the Amazon existed, and yet every one of them, every time the wing pattern was needed, reached into the same two-gene box.

What had evolved, repeatedly and independently, were the regulatory switches that turn the two genes on at the right places in the wing during development. In one of the moth species the switch turned out to be an inversion: a chunk of the chromosome physically flipped backwards in the genome, the same large-scale rearrangement an independently evolving butterfly lineage had hit upon some millions of years earlier. Convergent evolution at the level of the regulatory toolkit. The mechanism the moth used to find the switch turned out to be the mechanism a butterfly had also used. The genome, in other words, has a small repertoire of tricks for solving the predator-recognition problem, and lineages separated by a hundred and twenty million years keep reaching for the same ones.

There is a temptation to call this "evolution isn't random," and the paper's press release leans into the phrasing. The more careful claim is the one Bates would have recognised. The space of solutions to the warning-colouration problem turns out to be very small. Once a lineage discovers that flipping optix on in the right wing region produces a black-and-orange chevron, every subsequent lineage that needs the same chevron is statistically far more likely to discover the same switch than to reinvent a new colour pathway from scratch. Selection finds the toolbox. The toolbox is finite.

A self-taught hosier's son spent eleven years in a flood-forest watching the same wing patterns appear on the wings of unrelated butterflies, and called the phenomenon mimicry. A 2026 genomics consortium, working from his specimens and from descendants of his specimens still flying along the Solimões, found the two genes that have been doing the work for a hundred and twenty million years.

A bird on a branch, faced with a black-and-orange wing in 2026, sees what a bird on the same branch saw when T. rex was a young species: do not eat that one.

Bates would have approved.

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STEM 1848 to 1862, the Bates and Wallace Amazon expedition and the Linnean Society of London On 2 May 2026 an international team led by the Wellcome Sanger Institute and the University of York published in PLOS Biology 'Genetic parallelism underpins convergent mimicry coloration in Lepidoptera across 120 million years of evolution.' Working from whole-genome sequencing of seven species of Heliconius and Ithomiini butterflies and a day-flying Chetone moth, the team showed that across 120 million years of independent evolution Lepidoptera have re-used the same two genes, ivory and optix, to produce convergent warning-colour patterns. The protein-coding sequences are conserved; the evolution sits in the regulatory switches. One moth species deploys the genes via a chromosomal inversion identical in orientation to one independently evolved by a butterfly lineage millions of years earlier. The space of viable genomic solutions to the Batesian-mimicry problem is small, and lineages 120 million years apart reach for the same tools.

Sources & Verification (12 claims checked, 6 searches)

Henry Walter Bates (1825-1892) was an English naturalist, born in Leicester to a middle-class hosiery-trade family, who taught himself entomology and met Alfred Russel Wallace in 1844 when Wallace took a teaching post at the Leicester Collegiate School.

en.wikipedia.org — "Henry Walter Bates was born in Leicester to a literate middle-class family. He became friends with Wallace when the latt"
www.linnean.org — "Henry Walter Bates (1825-1892) was born in Leicester to a middle-class family and developed an early interest in entomol"

In April 1848 Bates and Wallace sailed together from Liverpool for the Amazon, planning to support themselves by sending specimens to their London agent Samuel Stevens; they arrived at Pará (now Belém) at the end of May 1848.

en.wikipedia.org — "In 1847 Wallace and Bates discussed the idea of an expedition to the Amazon rainforest, the plan being to cover expenses"

Wallace returned home from the Amazon in 1852; on the homeward voyage his ship the Helen caught fire in the mid-Atlantic and his entire collection was lost.

en.wikipedia.org — "Wallace returned in 1852, but lost his collection on the return voyage when his ship caught fire."
en.wikipedia.org — "On 6 August 1852, the Helen caught fire in the middle of the Atlantic Ocean. Wallace was forced to abandon ship and lost"

Bates stayed in the Amazon for eleven years, returning to England in 1859. He had sent home a total of approximately 14,712 species, of which approximately 8,000 were new to science. He sent his specimens via three separate vessels to insure against loss.

en.wikipedia.org — "When Bates arrived home in 1859 after a full eleven years, he had sent back over 14,712 species (mostly of insects) of w"

On 21 November 1861, Bates read a paper before the Linnean Society of London titled 'Contributions to an Insect Fauna of the Amazon Valley: Lepidoptera, Heliconidae,' which was published the following year in the Transactions of the Linnean Society of London (vol. 23, 1862, pp. 495-566).

en.wikipedia.org — "On 21 November 1861, Bates expounded his ideas on mimicry in his paper 'Contributions to an Insect Fauna of the Amazon V"
en.wikipedia.org — "Bates published his findings on mimicry in 1862 in the Transactions of the Linnean Society of London, having read the pa"

Charles Darwin, on reading Bates's mimicry paper, described it as 'one of the most remarkable and admirable papers I have ever read in my life.'

www.nhm.ac.uk — "Charles Darwin described Bates's article on mimicry as one of the most remarkable and admirable papers I have ever read "
en.wikipedia.org — "Charles Darwin commented that Bates's article was 'one of the most remarkable and admirable papers I have ever read in m"

Gregor Mendel began his pea-plant hybridisation experiments at the Augustinian abbey of St Thomas in Brünn (Brno) in approximately 1856 and published 'Versuche uber Pflanzenhybriden' in the Proceedings of the Natural History Society of Brünn in 1866; the paper went largely unread for thirty-five years until Mendel's work was rediscovered in 1900.

en.wikipedia.org — "Mendel conducted his hybridization experiments on pea plants in his monastery garden between 1856 and 1863. His paper Ve"

On 2 May 2026 a multi-institution team led by the Wellcome Sanger Institute and the University of York published in PLOS Biology a paper titled 'Genetic parallelism underpins convergent mimicry coloration in Lepidoptera across 120 million years of evolution.'

journals.plos.org — "Genetic parallelism underpins convergent mimicry coloration in Lepidoptera across 120 million years of evolution. PLOS B"
phys.org — "Researchers led by the University of York and the Wellcome Sanger Institute published in PLOS Biology that butterflies a"

The 2026 paper sequenced seven species of Heliconius and Ithomiini butterflies and a day-flying Chetone moth and found that all of them produce their convergent mimetic wing-patterns by re-using the same two genes, ivory and optix, with the differences between lineages located in regulatory elements rather than the protein-coding sequences of the genes themselves.

www.sci.news — "The study examined convergent evolution in multiple mimetic neotropical lepidopteran lineages including seven species of"

In one of the moth species the regulatory mechanism was a chromosomal inversion (a large chunk of DNA physically flipped backwards) that closely mirrors an inversion strategy independently evolved in one of the butterfly species.

www.sci.news — "In the moth, scientists found a surprising twist. It used an inversion mechanism (a large chunk of DNA flipped backwards"

Batesian mimicry, named after Bates, is the phenomenon in which a palatable species evolves to resemble a chemically defended (unpalatable) model species, gaining protection from predators that have learned to avoid the model.

en.wikipedia.org — "Batesian mimicry is a form of mimicry where a harmless species has evolved to imitate the warning signals of a harmful s"

Bates published his book 'The Naturalist on the River Amazons' in 1863, recounting his eleven-year expedition; it became one of the most widely-read natural-history travelogues of the Victorian period.

en.wikipedia.org — "Bates wrote up his findings in his best-known work, The Naturalist on the River Amazons (1863). It was widely praised as"