Episode 126 – Mimicry

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Communication is key among organisms. Various signals – sights, sounds, smells – can serve to warn, attract, or manipulate others. So it’s no surprise that many organisms have evolved to copy the signals of others for their own deceitful purposes. In this episode, we discuss the diversity and evolution of Mimicry.

In the news
Bryozoans in the Cambrian!
Early mammal-cousins and the origins of tusks
These Cambrian worms appear to be the earliest known ‘hermits’
Condors caught producing babies without mating!

Nature’s plagiarists

We’ve discussed convergent evolution on the podcast before, where two unrelated groups of organisms evolve similar traits for similar purposes. Mimicry also involves similar traits evolving in different organisms, but mimicry is about communication … or more accurately, miscommunication. Mimics copy the signals of other organisms, effectively pretending to be something they’re not, because that deceit is beneficial.

Here’s a classic example of mimicry.
On the left is Micrurus tener, a venomous Texas coral snake, whose bright colors are a warning of danger to any would-be antagonists. Image by LA Dawson, CC BY-SA 2.5
On the right is Lampropeltis triangulum, a non-venomous milk snake, whose similar colors have evolved to fool would-be antagonists. Image by LA Dawson, CC BY-SA 2.5

Mimicry typically involves at least one mimic species, at least one model (the species the mimic is mimicking), and at least one dupe (the species the mimic has evolved to fool). Not all mimicry is visual; mimics can resemble their models in terms of appearance, sound, smell, or other characteristics. And not all mimicry is defensive; mimicry can be useful for evading predators, fooling prey, or even convincing other species to do ones’ bidding.

There are many forms of mimicry, but the two most famous are Batesian and Mullerian, depicted here. Batesian mimics are harmless species that copy the warning signals of harmful species. Mullerian mimics are harmful species that share similar signals for mutual benefit. Image by Ian Alexander, CC BY-SA 4.0
Mimicry can be beneficial for securing food or even reproduction.
Left: A fly orchid’s flower resembles an insect and exudes chemicals similar to insect pheromones. These features attract pollinators. Image by Ivar Leidus, CC BY-SA 4.0
Right: A spider-tailed horned viper has a tail that looks remarkably like a bug. This lure draws in prey such as birds. Image by Omid Mozaffari, Public Domain.

Mimicry can involve the entire body, part of the body, or even features separate from the body, as in the case of cuckoo birds whose eggs mimic those of other birds, making it easier for the cuckoos to hide their own eggs in other birds’ nests.

Similar to mimicry is a phenomenon called masquerade, where an organism mimics an uninteresting object, as in the case of stick insects and leaf insects. This isn’t quite the same as mimicking another organism’s signal, so it is sometimes considered separately from mimicry.
Image by Fir0002, CC BY-SA 3.0
Mimicry can be difficult to identify in the fossil record, but it’s not unheard of!
Left: Artist’s reconstruction of Permotettigonia gallica, a leaf-mimicking katydid from the Permian Period, an example of ancient masquerade. Image by Garrouste et al. 2016.
Right: Amber-preserved fossil of Bersta, a predatory hemipteran insect from the Cretaceous Period whose striking similarity to harmless beetles might have allowed it to approach and attack unsuspecting prey. Image by Tihelka et al. 2020.

Mimic evolution is superficially easy to understand. If a species benefits from resembling another, natural selection might gradually improve that resemblance, whether the benefit is related to avoiding predators, nabbing prey, securing reproduction, or otherwise. But the details can get very complex.

The evolution of mimcry has been intensely studied and discussed, but can be very difficult to sort out because of its complexity. It can sometimes be difficult to identify exactly what benefit some mimicry provides, what organism is supposed to be fooled, or which organism is the model and which is the mimic. There are many cases of convergent evolution among mimics and many cases of imperfect mimicry.

Learn more

Mimicry in plants, 2016

The evolution and ecology of masquerade, 2010 (technical)

Evolutionary origins of vocal mimicry in songbirds, 2018 (technical)

Imperfect mimicry and the limits of natural selection, 2013 (technical, paywalled)

If you enjoyed this topic and want more like it, check out these related episodes:

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