Celebrating Bates

Henry Walter Bates gave the first known scientific account of mimicry in biological systems. To mark the bicentenary of his birth, we present a collection of content that reflects on his life and legacy.

This year marks the 200th anniversary of the birth of Henry Walter Bates, an English naturalist who formally introduced ‘mimicry’ as a scientific concept. We asked a range of researchers working on mimicry across biological systems to reflect on emerging questions in the field.

Mysterious cephalopod's fragile arms lure its food close enough for killing.

For Christine Huffard, the bipedal octopus walks a fine line.

Joana Meier is fascinated by the diversity and mimetic colour patterns of glasswing butterflies.

It is unclear how birds differentiate their own eggs from cuckoo’s eggs that parasitize their nests. Here, the authors develop a computer vision tool that simulates how brains process pattern information and show that cuckoos’ hosts have evolved unique egg patterns to distinguish their own eggs from a cuckoo’s.

Female common cuckoos often make a hawk-like call after parasitizing a host’s clutch. Here, field experiments show that this call increases the chances of parasitic success by diverting host parents’ attention.

Female cuckoos use predator-like calls to manipulate their hosts and reveal a new world of deception.

Ground-nesting birds actively choose backgrounds for their nests that enhance their camouflage, refining this choice across spatial scales.

Amy Eacock et al. examine the sensory input mechanism for slow colour change in the twig-mimicking caterpillars of the peppered moth. They find that this camouflage process does not require the use of eyes, relying instead on extraocular colour sensing.

Samuel Green, Rafael Duarte et al. use models of fish vision to quantify camouflage in green and red chameleon prawns against seaweed backgrounds. They find that while color change occurs over longer periods of time, prawns modify their behaviour in the short term to select color-matching backgrounds.

Radford et al. monitored cattle marked with artificial eyespots in non-commercial cattle farms in northern Botswana, and demonstrate that cattle with these eyespot markings were more likely to avoid predation by large carnivores. Their findings have applications as a cost-effective tool to reduce livestock predation by ambush predators.

The cuttlefish Sepia officinalis uses high-dimensional skin patterns for camouflage, and the pattern matching process is not stereotyped—each search meanders through skin-pattern space, decelerating and accelerating repeatedly before stabilizing.

Functional characterization and modeling of a mimetic butterfly’s trichromatic visual system sheds light on the cues used for mate detection in the context of mimicry.

A diverse range of pathogens produce molecules that mimic host cell components to subvert host cell functions. Elde and Malik highlight the various types of mimicry used by pathogens and the measures that host cells use to counteract the mimics' effects.

Although batesian and müllerian mimicry were identified 100 years ago, the dynamics of mimicry between unequally defended prey remain unresolved. This paper experimentally tests the contrasting theories, demonstrating that unequally defended (even edible) mimics gain survival benefits from their association with one another.

The latest turn in studies of mimicry in the animal world involves great tits as predators and almonds as prey. When it comes to being unpalatable, it seems that some mimics may neither flatter nor deceive.

Müllerian mimics have convergently evolved similar warning colouration because of the advantage of strength in numbers. However, it is not clear if this effect is sufficient to maintain coexistence when competitive exclusion would be expected to favour one mimic at the expense of the others. Here, Müllerian mimicry in catfish is characterized, and it is shown through morphometric and stable isotope analysis that mimics do not occupy identical niches, so are not in direct competition, thus explaining their coexistence.

Mutualism can be a double-edged sword if the animals concerned also compete for food. This may explain the discovery that catfish mimics in the Amazon rarely engage in mimicry with related species. See Letter p.84

In hoverflies with a small body size, even imperfect Batesian mimicry suffices to limit predation because they are not subject to particularly intense selection.

Some species evolve to resemble another species so as to protect themselves from predation, but this mimicry is often imprecise. An analysis of hoverflies suggests why imperfect imitation persists in the face of natural selection. See Letter p.461

In Müllerian mimicry two or more harmful species share a similar appearance for mutual benefit. This study identifies a large Müllerian mimicry complex in North American velvet ants, where 65 species mimic each other through shared colour patterns gained as the result of independent evolution.

It is unclear how mimetic radiations, the evolution of a species to resemble different model species, contribute to speciation. Here, the authors show patterns of mating behaviour and genetic divergence, suggesting that mimetic divergence has promoted incipient speciation in a group of Peruvian poison frogs.

The coexistence of alternative antipredatory strategies is poorly understood. Here, the authors show that warning colours lose their effectiveness when passerine birds, their main predators, fledge their young, which suggests that predators’ learning impacts selection for conspicuous warning signals.

Toxic and venomous species often have conspicuous warning colouration that is mimicked by harmless species. Here, Davis Rabosky et al. combine phylogenetic and biogeographic analyses to reveal that mimicry of venomous coral snakes has been a major driver of snake colour evolution in the New World.

Deadly coral snakes warn predators through striking red-black banding. New data confirm that many harmless snakes have evolved to resemble coral snakes, and suggest that the evolution of this Batesian mimicry is not always a one-way street.

Many insects mimic plants in order to avoid detection by predators. Here, Garrouste and colleagues describe a katydid fossil that extends the record of leaf mimicry to the Middle Permian, more than 100 million years earlier than previously known fossil specimens of plant mimicry.

Olivia Walton and Martin Stevens revisit the classic example of the peppered moth, objectively quantifying moth camouflage and predation risk. With bird vision models, pale individuals more closely match lichen backgrounds, and survive better, providing support for this iconic example of natural selection.

Many abiotic and biotic factors shape the macroevolution of phenotype, but these factors are rarely disentangled across large radiations. Here, Miller et al. investigate plumage evolution across woodpeckers, finding influences of habitat and climate, but also convergence apparently driven by mimicry

Kathleen Prudic et al. examine the persistence of mimicry in viceroy butterflies in locations with low model abundance. They show that when queen butterflies are less abundant, viceroy butterflies become more abundant, but also increase their chemical defenses to gain protection from predation.

Around 20% of female hummingbirds have plumage that is characteristic of the males of the species. Evidence for why this happens offers a surprising perspective on how evolution helps to maintain colour variations.

Using a 50 year time series of photos of cuckoo finch eggs and those of its host, prinia, the authors document that cuckoo eggs evolve towards prinia eggs, but progressive evolution of prinia eggs away from cuckoo eggs results in no detectible increase in mimetic fidelity.

This study revealed that cuckoo hosts coordinated two evolutionarily successive but opposing behaviours by reshaping the instinctive egg retrieval reaction to different flexible reactions during their coevolution with parasitic cuckoos.

Selection is expected to act differently on aposematic and cryptic species. Analysis of wing images revealed that camouflaged moths exhibit higher wing pattern variability than aposematic moths, supporting the theory that camouflaged species display more variability, consistent with anti-predator strategy.

Birds have an excellent ability to learn to discriminate harmless insects from those that they mimic on the basis of subtle differences in appearance.

Sequencing of the genome of the butterfly Heliconius melpomene shows that closely related Heliconius species exchange protective colour-pattern genes promiscuously.

Little is known about the genetic basis of convergent evolution in deeply diverged species. Here, the authors show that variation in the WntAgene is associated with parallel wing pattern variation in two butterflies that diverged more than 65 million years ago.

The phenomenon of sex-limited mimicry is phylogenetically widespread in the swallowtail butterfly genus Papilio — now, a single gene, doublesex, is shown to control supergene mimicry, a finding that is in contrast to the long-held view that supergenes are likely to be controlled by a tightly linked cluster of loci.

Variation in an evolutionarily conserved sexual-differentiation gene, doublesex, has been found to explain how females of one species of butterfly mimic the colour patterns of several toxic species to avoid predation. See Letter p.229

The evolution of genetic dominance in polymorphic traits remains poorly understood. Here, the authors show that distinct dominance mechanisms have evolved in association with supergene inversions controlling wing pattern in Heliconiusbutterflies, in response to strong selection favouring mimicry.

Viral apoptotic mimicry, defined by the exposure of phosphatidylserine on the pathogen surface, is emerging as a common theme used by enveloped viruses to promote infection. In this Progress article, Amara and Mercer discuss how viruses acquire phosphatidylserine and how this mimicry might facilitate cell entry and evasion of the immune response.

The common cuckoo lays its eggs in nests of a variety of species and their eggs mimic the ones of their hosts. Here, the authors show that blue egg colouration in the common cuckoo is maternally inherited, originated in Asia and then expanded to Europe.

Wing colour patterning of multiple species in the butterfly genus Heliconius is controlled by differential expression of the gene cortex, a member of a conserved family of cell cycle regulators.

The mutation responsible for the black carbonaria morph of the peppered moth is identified as a transposable element within the cortex gene.

Wing pattern mimicry in the butterfly Papilio polytes is controlled by a single Mendelian locus, the mimicry supergene doublesex. Here, Zhang and colleagues reconstruct the complex evolutionary history of the doublesex supergene and mimicry in the Papilio polytes species group.

Vavilovian mimicry is the phenomenon whereby weeds evolve to resemble co-located crop plants through unintentional human selection. Here the authors compare mimetic and non-mimetic populations of Echinochloa crus-galli (a weed mimic of rice) to characterize the genomic underpinnings of this case of Vavilovian mimicry.

Takuro Iijima, Shinichi Yoda, and Haruhiko Fujiwara investigate gene networks controlled by the mimicry-associated allele of doublesex, dsx-H, in butterflies that mimic an unpalatable species. They find that dsx-H has a dual function: it induces mimetic gene networks and represses non-mimetic gene networks, explaining its key role in the switch between mimetic and non-mimetic female forms.

Polymorphic mimicry in Papilio swallowtail butterflies is thought to have had multiple independent origins. Here, the authors show that the gene doublesex controls mimicry across multiple species, but with distinct alleles that may have originated from an ancestral polymorphism.

Camouflage is a widespread phenomenon in nature, and the orchid mantis is a particularly striking example. Here the authors use evolutionary genomics to uncover the genetic mechanisms behind the colour and morphology that produce innovative camouflage in the orchid mantis and dead leaf mantis.

The authors investigate the genetic basis of inter-sexual mimicry in Ischnura elegans damselflies, where females are polymorphic and one female morph mimics males. By combining genomic, transcriptomic and phylogenetic evidence, they identify a causal locus and structural variants associated with the evolution of female polymorphism and male mimicry in this species.

Venomous animals typically disrupt nervous, locomotor, and cardiovascular systems to incapacitate prey, but certain fish-hunting cone snails evolved toxins that specifically target glucose homeostasis. Here, the authors show the combinatorial nature of weaponized insulin and somatostatin mimetics, exemplifying the use of combinatorial chemical mimicry for prey capture.

Viruses often evolve molecular mimicry with host proteins for immune evasion. Here the authors assess short linear mimicry of 134 viruses to find abundance of such mimicry in herpes and pox viruses, while overlaps between Epstein-Barr virus antigens and auto-antibodies from patients with multiple sclerosis hints at a crosstalk between viral infection and autoimmunity.

Multi-omics analysis reveals that a 254-bp transposon induces defensive camouflage in an alpine plant and reduces herbivory by caterpillars of a specialist butterfly. Protective effects of this camouflage are reflected in the long-term dynamics of co-evolving plant and butterfly populations.

Genomic and demographic analysis of an alpine plant–insect herbivore system shows that plants can use defensive camouflage to escape herbivores in an eco-evolutionary game of hide-and-seek that has been playing out for millennia.

First-instar orchid mantis nymphs avoid predators by mimicking black-red assassin bugs, whereas those in later instars avoid predators and attract prey by camouflaging themselves as lighter-coloured flowers. Here the authors use developmental transcriptomics, evolutionary genomics and predation experiments to reveal that this ontogenetic colour change is regulated by a pigment transporter called Redboy that emerged in Polyneoptera 284–197 million years ago.