One main playing field of speculative biology concerns life somewhere else than Earth, such as my Furaha project. Another describes how life on Earth might have evolved if some event in the past had taken a different turn, such as Dougal Dixon’s book The New Dinosaurs, and the third, the subject of this post, deals with life on Earth in the future.
Well-known examples are Dixon’s After Man and the French book Demain, les animaux du futur (see posts A, B, C, D and E). While these projects discuss various animal clades, one group of animals receives less attention than it deserves, based on ecological clout, numbers of species and of individuals: insects!
That changed with a new speculative biology book about future insects. Before you run to the nearest bookshop, you should realise that it is in French. At the time of writing the authors do not yet know whether there will be versions in other languages. The book is called Les insectes du futur, a title that should be understandable without knowing French. The subtitle is Petite entomologie post-effondrement, which means ‘small entomology after the collapse’. The book was published last September by Belin in France. The first author is Lucas Etienne, a researcher who designed the arthropods and made the illustrations. You may already know the second author, Jean-Sébastien Steyer, as he was one of the two authors of Demain, les animaux du futur ; he is a palaeontologist (see his book Earth before the dinosaurs) and has published various books popularising science.
The book counts 163 pages and describes a large variety of insects and other arthropods, as told by two human researchers who make their way from Paris to Monaco in the year 2499. The protagonists make this journey after leaving the underground collection rooms of the Muséum d’Histoire naturelle where they sat out a nuclear war. They encounter many species of arthropods that are as new to them as they are to the reader. The book is divided into chapters that describe ecosystems and various biological principles, such as camouflage, symbiosis, parasitism, flight and adaptations to aquatic life. Let’s have a look at a few organisms.
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| Click to enlarge; © Belin Éditeur/Humensis, 2025 |
Nepa dendrobates
This animal may look like a tropical frog, but it is in fact an insect of the clade Hemiptera. The bright dazzling colours of the frog it mimics are a warning to would-be predators that these frogs are poisonous. The insect mimics the frog in colour and shape, so predators should mistake the tasty insect for a poisonous frog and stay clear. This is a nice example of Batesian mimicry, something than can be described as a sheep in wolf’s clothing. I wondered what happens if some predator that never eats frogs comes across such an insect. That predator would not be warned off by the colours because it never eats frogs, poisonous or otherwise. It would still not eat the insect as it wouldn’t recognise the insect as an insect, but as something inedible. Does that turn the effect into simple camouflage rather then Batesian mimicry? That sounds like a nice subject for a biology examination.
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| Click to enlarge; © Belin Éditeur/Humensis, 2025 |
Aquatic ants
Quite a few insects adapted to a life underwater, but never ants, or so I thought. I was wrong: there is an ant that dives into the fluid of pitcher plants to steal animals that fell in, and there is a mangrove species that allows its nest to be inundated by the tide. Etienne and Steyer developed their own aquatic ants. They developed gills, have grown considerably larger than any terrestrial ant and have become good swimmers. These ants are still colonial and still build their own housing, which in this case resulting in underwater ant cities. These marine ants developed symbiosis with corals, which is a very interesting idea, so altogether they paint a very intriguing picture.
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| Click to enlarge; © Belin Éditeur/Humensis, 2025 |
Abyssal wasp
This wasp descendant can grow to an astonishing length of 60 centimetres. It is bioluminescent thanks to symbiosis with luminescent bacteria. Unfortunately, the book provides little detail how it lives, although it is clear that it has lost its sting.
The story takes place in the year 2499, almost 500 years from now. That may be long enough for mankind to further change the climate and to damage or destroy many ecosystems, bringing about an overall collapse. But how much biological evolution can take place in that time? In other words, what is the maximum speed of evolution? That is probably complex. Factors that must play a role are how large the pressure to change is, such as due to a quickly changing environment and mixing species that were previously separated. The amount of genetic variability and the mutation rate would also be important modifiers of change. The morphological changes in the insect book are so large in such a short time that evolution here has jumped, something known as ‘saltation’.
One theory of saltational evolution by Goldschmidt described ‘hopeful monsters’ that came about through very large mutations, large enough to explain the advent of new species. This concept of saltational evolution was never wholly discarded and new papers keep on appearing on the subject. I do not know enough about it and cannot therefore afford a strong opinion on the matter. Readers of this blog will know about ‘punctuated equilibrium’, a theory stating that species do not change for a long time but may then suddenly undergo a major change. At present, there is evidence for both long periods of stasis as well as for evolutionary jumps. In short, the speed of evolution can vary.
But the future insect book still forces a closer look at that speed. The fossil record does not exactly have a nice temporal resolution, with a complete fossil every hundred generations or so.
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| Click to enlarge; source: wikipedia |
This Wikipedia graph neatly explains that gradual change over 10,000 years will show up as a qualitative jump if you only sample the record once every 10,000 years. But the graph is quite hypothetical. Very well, let’s hypothesise a bit ourselves. Making an insect look like a frog must involve changes to a great many genes. It seems extremely unlikely for all genes involved to mutate in the correct direction at the same time (but if this does happen, you might get an evolutionary jump). It seems more likely that weeding out any variant that reduces ‘frogginess’ requires untold encounters between predators, the insect and the frog. How many generations would that take? Likewise, adapting insects to water is likely to go through successive stages, perhaps starting with short dips to get food. From there, you can expect changes allowing the animal to last longer under water. I would not be surprised that breeding under water would be one of the last changes to take place. Again, it seems unlikely that all features would change in the correct direction at the same time.
I understand the style figure of using human guides to show these new animals. The alternative would have been to move forward a few million years and to depict the animals as they are, without human interest. Would that have been better? That depends on what you want from such a book. The authors must have had great fun using their new arthropods to illustrate various biological principles such as Batesian mimicry. They did not in fact use the term Batesian mimicry; instead, they chose to teach by example, making their book highly accessible. That is an advantage and does not harm the fun. Come to think of it, showing how biology works is, for me, the essence of why speculative biology is fun.
