Evidence exists that Hymenopteran eusocial insects possess higher social and logical intelligence than most other insects (i.e. facial recognition in wasps, limited self-awareness in ants), suggesting that the two traits have some correlation, which inspires this question.

I am working on a species of eusocial creature that supposedly evolved from a Hymenopteran-like arthropod. An increase in size and body mass allows the species a degree of higher intelligence. However, the creatures still retain their strict biological caste system with single reproducing queens and large numbers of specialized (and expendable) non-reproductive workers, who act only in the interest of the colony.

Colonies rarely cooperate with one another, and most of the species’ lifespan is spent collaborating only within their own hive, which (I think) would limit the development of communication and exchange of ideas that would result in greater intelligence. Also, the expense of growing larger creatures with complex brains may conflict with a biological system that constantly produces/replaces hundreds of short-lived, self-sacrificing workers.

Could it stand to reason that a eusocial caste system described above could survive a spike in intelligence?

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    $\begingroup$ Not clear why you consider that a spike in intelligence would afftect the basic biology of the species. Ffor example, humans are highly intelligent, yet pregnancies still take nine months, and our infants are born helpless and require extensive care. $\endgroup$
    – AlexP
    Jul 18, 2022 at 13:42
  • $\begingroup$ @AlexP To clarify, the main factors I’m thinking about are the implications of increased intelligence (I.e. increased brain and body mass might decrease the population of a colony dramatically enough to alter social structure) or that the basic biology might prevent an intelligence spike in the first place (I.e. limited freedom to innovate). $\endgroup$ Jul 18, 2022 at 13:51
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    $\begingroup$ Worldbuilding as an art isn't bound by any concept of possibility. Anything you can imagine you can build a world where that is the case. A lot of science fiction is build around the idea of exploring fantastic, and impossible what ifs. The authors didn't ask "is it possible?" but "what would it be like if it was?". In you world it may be possible for a eusocial caste to become intelligent, in your world it may be not. As written this question isn't really answerable, since as worldbuilder you get to decide what the answer will be. $\endgroup$
    – sphennings
    Jul 18, 2022 at 14:51
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    $\begingroup$ I try not to vote to close Qs from new users. Are you asking us for permission to use the idea? Biological caste issues have been explored before (e.g., Star Trek). If there's no way around the biology, it will remain in some form. The problem with intelligence is your parenthetic, "(and expendable)." No intelligent creature perceives itself as expendable. So, do you have a specific question? Because from a worldbuilding perspective the answer is, "yes, if you want it to. No, if you don't. Depends on how you write your story." $\endgroup$
    – JBH
    Jul 18, 2022 at 15:32
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    $\begingroup$ I can't help but think of the Zerg and Kerrigan's path to becoming "Queen of Blades". $\endgroup$
    – hlongmore
    Jul 18, 2022 at 23:33

7 Answers 7


TL;DR: Yes, it already exists.

Note: @Daron pointed out that variations in insect development actually are called castes. I had the misconception that the original question was attempting to anthropomorphize non-biologically enforced castes, but the entomologists already did that for him.

There are a couple of cases you have to consider, based on speciation. In the first the two creatures belong to different species, for instance humans and dogs. We've basically bred dogs to be subservient, and even if they achieved human-level intelligence, we kill off any dogs that try to get above their place. When a dog bites a human, the dog is killed. That's a hard rule of dog breeding.

In that case, your question is, "Is there an intelligence level at which dogs will no longer accept their subservience?" This is a serious question. The smarter dogs are more teachable, but they're also more prone to deciding that they don't need to obey you after you've left the room.

In this case I believe it can be maintained, but only at the cost of increasing cruelty as the subjugated race gains intelligence.

The other case is where some chemical or physical process adjusts the phenotype during development. This is what happens when a worker honey bee is fed royal jelly. I don't know the specifics of it, but it makes the bee capable of laying eggs, but less capable of foraging for food.

The question here is whether or not the workers would chafe at not being able to lay eggs, and seek out a method of inducing the development later in life.

Humans are currently running into a similar issue with our male/female caste system. We socially assign roles based on whether a person has expressed male or female secondary sexual characteristics. All one race, but we decide that those with boobs are less capable of making authoritative decisions.

With that example in mind, then, yes, an intelligent species can evolve with such a caste system, because we have done it. Humans like to think that they're too intelligent for such things, but that's mostly hubris on our part.

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    $\begingroup$ Quick honeybee fact dump, drones are male bees, so they are never fed with royal jelly and can’t develop into queens. You are probably thinking of (female) worker bees. Even they need to be fed royal jelly as larvae; by the time they eclose as adults they have already committed to one morphology or the other. $\endgroup$
    – Ottie
    Jul 18, 2022 at 20:13
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    $\begingroup$ Thanks, @Ottie. I edited my answer based on this. The "already committed to one morphology or the other" doesn't seem to be stopping humans from looking for a solution. $\endgroup$ Jul 18, 2022 at 20:54
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    $\begingroup$ To say nothing of systems like slavery in the US based on race. $\endgroup$
    – s3raph86
    Jul 19, 2022 at 0:32
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    $\begingroup$ Ants have many biological castes. For example worker and soldier ants are different castes. This terminology is standard. When referring to ants there is no confusion caused by how the ant castes are different from the Indian social castes. $\endgroup$
    – Daron
    Jul 19, 2022 at 13:52
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    $\begingroup$ @Odalrick: That was the prevailing view - Hamilton's hypothesis that haplodiploidy makes eusociality more likely - but it turns out that haplodiploid species aren't more likely to be eusocial, see journals.uchicago.edu/doi/full/10.1086/677283. Examples of non-haplodiploid eusocial species include termites and naked mole rats. $\endgroup$ Jul 19, 2022 at 15:30

A lot depends on the “type” of intelligence you are talking about. Human intelligence will be the easiest to write, but you are essentially creating insect-shaped humans for you story. You could always break the mold and explore other types of intelligence. For example, your bugs could have the ability to recognize usefulness in potential applications. They find a prey species they enjoy eating, recognize it thrives near certain plants, transplant said plants to near their colony, and have domesticated animals after a few generations. There wouldn’t need to be any actual communication, just recognition and mimicry. Copying what others did before you works fine. There are limitations to this type of intelligence, but it can allow for rapid environmental adaptation without the need for communication or self-awareness.

I think one issue you are having is that you are thinking about it from the perspective of a human. Try and shift your viewpoint to that of your intelligent insects. You are born into a caste system which has existed in similar form for millions of years. This caste system is literally programmed into your DNA. Fighting against your ingrained genetic programming would indicate insanity, or some other genetic deficiency. Societal culture would likely work to encourage the continuation of such a system. As your insects grow up, they are taught that this is the way the world works. This becomes an ingrained worldview backed by genetic drive. Your world works this way from the moment you are born, so why would you fight it? The world operating differently from what you expect would cause significant stress.

This doesn’t mean that your intelligent insects are unable to conceive of what life would be like if they had been born differently. A worker might wax poetic about how much he/she could accomplish in service to the hive if he/she lived as long as the queen. They could ponder the meaning of life, and have their religion provide the answer that service to the hive is the highest form of holy worship. An intelligent mind might even ask questions about other hives, and if they have similar beliefs. That is the thing about intelligence, it lets us explore beyond what we can see immediately around us. It can also help lead to longer lifespans as risky behavior is recognized and methods of decreasing the risk are determined.

One issue with a short lifespan, is the limiting of time needed to learn complex information and/or skills. This is not an issue in an organism operating on instinct, as there is little/no need to learn information. It becomes an issue when you are trying to advance technology beyond simple pointed sticks and clubs. How can you teach a being with a lifespan of a few years enough to let it improve upon what it has learned? A stick might be better for digging as it can be replaced when it breaks. Adding a hard rock to the end of the stick improves it a bit. Eventually you run into a wall where the information needed to make a steel shovel is more than can be learned before an organism dies. It is hard to imagine all of those steps being taken with organisms, who each know a small portion of the process, resulting in something complex. This would lead to your bugs turning levers for the good of the colony and the results being starships. You can hand wave this by cheating and giving your organisms eidetic memories which allow them to instantly memorize anything they see and hear, but that is tacky.

As for communication and cooperation, intelligence can allow organisms to overcome knee-jerk instinctive reactions. A worker who finds a wounded worker from another colony could overcome an urge to kill the “enemy” worker, as it is no threat. Intelligence can also mean empathy. Feeling bad about the condition of the injured worker could lead to the uninjured worker providing aid. This aid might open doors and allow for the exchange of ideas.

A lot depends on the purpose of your story. Your bugs will need to have the type of intelligence which is best suited for getting the message of your story across to the reader. If the purpose is to simply explore this new world and the implications of it, then pick the aspects of intelligence you find most interesting to explore. If you want to examine overcoming genetic drives, then make those aspects of your species a primary driving factor and pit your main characters against them. They might want to kill the neighboring colony, but if doing so will result in their own destruction then that is not an option regardless of their feelings. The world exists as a medium for telling your story in the way you intend. All of its aspects should reflect that.


Long-lived, long-distance forager honeybees

I'm not 100% sure I've understood your question, but I'll take any opportunity to go on about bees, so.

Honeybees are eusocial insects capable of abstract thought, mental navigation maps and social exchange of complex foraging information. One aspect that many of these papers don't necessarily highlight is these experiments are all carried out of foraging bees.

The caste system in honeybees is peculiar compared to, for example, ants, in that all bees except queens and drones go through the various castes as they age - starting out close to the "core" of the colony with jobs such as tending to the eggs and pupae, and then moving closer to the surface, handling food and waste, then guarding the boundaries of the hive, until, at the end of their life, they start to leave the colony to forage. Foragers actually grow new neural pathways in preparation for this step. In particular, they build up their mushroom bodies[1] which are the learning and memory structures of the insect brain and generally considered the "higher order processing" computational centre in invertebrates.

But forager bees are doomed. They typically only live 2-3 weeks after leaving the hive. During this time, they are able to feed themselves on nectar while on a forage (they consume a stupendous amount of energy!) but they are still shackled to the hive for other nutrients, since the ability to digest protein is restricted to a specific, hive-bound caste. Interestingly, if the hive experiences a collapse, some foragers will move back in and "revert" to the indoor types[2] that have been depleted; if they do, then their life expectation can increase to even several months.

As they reach the end of their brief outdoor life, their brains rebuilding themselves for the beauty and complexity of the natural world, these foragers become more and more adapted to the outside world. Their accumulated experience makes it easier for them to navigate and their foraging strategies more effective. I wonder what would happen if they didn't have to die so soon?

Maybe the landscape that your bees forage on requires very long trips, so the foragers can't reliably come back to the hive between forages. Maybe this leads them to retain their own protein-digesting enzymes. Maybe, with time and nutrients, their brain can keep growing, the pruning of experience offset by fresh new connections. Maybe the additional range they gain leads them to develop intermediate "cache stations" for pollen. Maybe these become local hubs where foragers who have ventured far afield waggle dance to the new explorers about their adventures. Maybe they compete to gain "followers" - more foragers on the same route means a better chance at an unbroken supply line back to the hive. Because as much as they know that they can never go back, the hive is still home.

[1] yeah, not a good name, I mean they are very vaguely mushroom-shaped if you squint, I guess
[2] I can't seem to find the ref to this, I wonder if it's a beekeeper myth? But my pubmed-fu is rubbish lately.

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    $\begingroup$ This addresses my concerns precisely- Apologies for vague phrasing. I was thinking of basing the critters off of wasps, but honeybees may be a better alternative! $\endgroup$ Jul 18, 2022 at 20:02
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    $\begingroup$ This is particularly interesting because most eusocial sci-fi aliens go the route of "the queen is the only sentient one" and this answer makes a strong case for the workers gaining sentience first! $\endgroup$
    – codeMonkey
    Aug 9, 2022 at 16:10

One example of an intelligent species that keeps a caste system is humanity. Over large parts of the globe and huge spans of history, women where pushed to work in the domestic sphere, and where often pushed out of certain castes (warfighting beeing the prime example). Never uncontested, never to 100% effect but the push was and is there. But that's not what you are asking about.

I think your concept faces several big questions:

  • How did it come about?
  • What is the relationship between queen and hive?
  • How does it work energy wise?

I think Otties answer contains an excellent idea that I will borrow, distort, and build upon - long lived foragers who learn and aquire some intelligence. At one point in their life, they become to frail to go on forageing, language developed partially through imparting experiences on the younger flock. The elders (as I will call them from now on) mostly sit at the nest. Not every member, not even a majority, reaches this age. If need be the elders allow some culling among their young ones (and possibly among themselves). This is one solution to the energy puzzle. The other one is that these beasts are very efficient foragers and activly terraform (to a greater extent than even beavers or certain ants do so) their environments.

Because all worker castes are essetnially the same animal they share the same capability to learn and think. Also, more brainpower turns out to be useful in nest building or rearing the young (for example only foragers need language but the language skills develop faster when the specialized nursing cast also has language capability). So at first, the more capable brain is about as useful as male nipples for these non-foraging castes, but once language enters the game, these capabilties become useful and are selected for.

The queen is not necesarily as intelligent, because laying eggs does not require much thinking. If intelligent, they could be one of the elders. Or they would be the egg laying machine, adminstered by the elders.

In this answer I treat the elders as a homogenous group. What social structures they give themselves is pretty open. There could be ruling clique of relativly youg, strong elders or even one strong'man'. There could be an athenian style democracy. There could of course be a roughly egalitarian society, this is even likely. One thing that was very important in early civilizations, possession (or right to use land) that could be passed down through the generations, would play no role in a hive. It will be an interesting question what, then, the chief conflicts ithin such a society will be about.

  • $\begingroup$ It was my impression that castes separate otherwise biologically identical species so a male/female split is not a caste system. Considering we have actual caste systems in history (e.g. class systems, servants, slaves) based on arbitrary factors (lineage, nationality, and race, respectively)I find it odd that you would use such an incorrect example. $\endgroup$
    – uberhaxed
    Jul 19, 2022 at 17:54
  • $\begingroup$ Humans are very prone to creating in/out groups and thus castes based on appearance and behavior. This is often fear/dominance based and becomes more and more prominent when puberty hits. Just look at any junior high or high school. Despite our intelligence, we are very, very driven by our biology. Those drives are just interpreted through the lens of our society's culture. Economics didn't really get off the ground on strong predictability until it finally acknowledged that we are far from the cold, logical creatures they originally modeled us as. $\endgroup$
    – user53931
    Jul 20, 2022 at 14:37

Intelligence is always tricky... as humans, we tend to think of it as something it isn't. You imagine that there is this being (and that it's an individual), and that it can communicate with you and hold something you'd call a meaningful conversation. That it has a self-awareness and some innate drive to do things some of which at least won't pertain to its survival, prosperity, and reproductive success. You know, that it has hobbies or curiosity, that it responds to novel stimuli in a manner that would make sense to you (or at least could make sense to you if you tried to make sense of it).

That's not intelligence. It's a trait or group of traits we'd call "human-like" for lack of a better term.

If we explore a much more limited definition of intelligence, it might be helpful in answering your question. Imagine a biological organism (or member of a super-organism in your case). It has a large and developed brain/brain-analog (some organ that computes). This species is capable of high technology or will be capable of it soon (in the real world, ants invented agriculture 4 million years ago, so even mindless beings can have some technology). This species responds to novel threats and environments at a speed beyond which evolution is capable of.

The species very well might have metallurgy or something comparably remarkable (something humans might be envious of). It has or soon will have machines capable of multiplying work (levers, pulleys, etc). It has or soon will have machines capable of performing work (steam engines, electric motors, etc). If humans were to show up with a "take me to your leader" sign held in their hands, they'd recognize it as a situation that has never occurred before and one in which a quick mindless reaction would be undesirable.

Are these beings even individuals? Would they think of themselves as conscious like we do? If communication was established, would they think of consciousness as a valid concept at all? Would they bother to communicate beyond that which was necessary to solve communication? Are they capable of deliberate deception? Are they capable of imagining a need for deception?

If you sat down with one and tried to have a conversation and supposing it responded, would it even seem intelligent to you or would it be like talking to malfunctioning software?

Such an intelligence as this would allow the species to deal with novel threats (or even form symbioses perhaps). It would allow them ever greater levels of technology. And it wouldn't interfere with the traits that we like to think of as "hive-mind" in our favorite fictions. I assert that this isn't incompatible with your species and its biological caste system.


In a Eusocial organism, selection operates at the hive level†, and it's at that level you should be looking for intelligence. It's not that every worker is going to be intelligent, but that the hive itself is. That could operate through specialised thinker castes, it could operate through emergent intelligence in the collective (think how ant scent trails work, allowing the hive to find complex near-optimal solutions while each ant is individually operating only simple rules), or it could be that only the Queen is really high intelligence. However it works, if you have high intelligence then hives are going to be communicating with each other, and that communication is going to be key to both the development of intelligence and the development of technology and culture.

†In the main, but there's actually a whole load of really interesting evolutionary conflict cases here which can undo eusociality but they're not relevant to the question.


Yes most certainly, you can't entirely get away from your biology.

Look at humans, the gender binary can be look at as soft biological cast system. While much of the gender divide is social, yet it has a biological component which is why the role for men and women in different societies are so similar dispite differences in distance, environment, culture and religion.

Even today this still effects us this is why female presidential candidates have such difficult competing against there male counter parts.

Let's not forget pheromones, in most hives the queen omittes pheromones to control the hive. If the hive were more intelligent they might be able to figure out that the queen is controlling them, but that doesn't mean they will be able to do anything about it.


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