Do insects have brains – Ranked by Size

The discussion over whether insects are sentient beings has evolved with cutting edge research and observations in the past few decades.

The discussion is no longer merely philosophical. Scientists have shown adequate proof that insects do possess the ability to, and demonstrate, higher functions common to beings that possess certain elements of a functioning brain.

Before we review some of the findings, though, let’s first begin with our understanding of how the neurons and synapses fire in an insect, contrasting with what happens in an insect’s brain.

It should be noted, as further expounded upon below, that the concept of a brain is radically different for an insect – which means that they should not be judged by our standards.

Having said that, we present ten distinct behaviors and responses that point to insects being capable of higher functions that would not be possible through reflexes and physical instincts alone.

What Does It Mean to Have a Brain?

From the point of view of us humans, our brain is the organ that controls our bodies. A database that stores not only how to move, breathe, and survive, but also allows us to feel emotions, thoughts, decisions and other finer feelings. 

Humans use the knowledge of what they’ve learned before, along with some inherited traits hardwired into our neural and physical pathways, to help make decisions in the present moment.

With the help of memory, a human can apply previously learned skills to get through their life as needed.

Thanks to emotion and ego, the human can comprehend when a situation isn’t going along as desired and can change their behavior to achieve their desired results.

The dictionary defines “smart” as having or showing quick-witted intelligence. “Intelligence” is the ability to acquire and apply knowledge and skills.

With these definitions, it’s rather easy to assume that these two words could also be applied to insects.

That would mean that for insects to show intelligence, they would have access to memories, they would possess the emotions to recognize which actions would fulfill their needs, and then be able to commit those actions.

The Human Brain vs. a Typical Insect Brain

Humans, and all creatures with a backbone and/or spinal column, have a midbrain, giving us awareness of our world from a singular perspective.

Recent research findings suggest that an insect’s central nervous system is capable of taking care of some of these higher functions.

To summarize, we could say that while our large neocortex definitely gives us a better perspective, it does not mean insects do not possess a certain level of consciousness. 

It’s important to note that insects typically have three lobes to their brain, all located in the head. These lobes are called the protocerebrum, deutocerebrum, and tritocerebrum.

This area holds all the insect’s neurons, but in far smaller amounts. For example, a bee has about one million neurons, while the average human has about 86 billion.

These three sections work together to bring in stimuli from the outside world to other sections of the brain to react accordingly. 

The protocerebrum has mushroom bodies within it. These bodies control the input of information through the eyes, a transfer section, and an output section.

Studies are finding that there is a link between the size of these mushroom bodies and the insect’s memory.

Flies can remember traumatic experiences from the recent past, for example, and they won’t return to that food source for a time because of it. 

Does Size Matter? How Do We Gauge Higher Brain Functions?

Of course it does, but only to a degree. We are not expecting an ant or a fruit fly to write an opera or debate logic.

In the context of how they have evolved, insects did not need to possess large and complex brains like we humans possess. 

The point, though, is that insects do exhibit certain traits and behaviors that speak to a higher brain function than they may normally get credit for. In no particular order, they include:

• Memory
• Ego
• Emotion
• Communication
• Recognition
• Problem Solving
• Decision Making
• Quick Response, prompt
• Awareness

We will discuss examples of each of these behaviors next.

1. Memory

The butterfly is an unlikely thought when it comes to memory, as they carelessly glide through flowers. However, their memory is beginning to get some attention.

Studies have established that butterflies do remember which flowers they have been to, and what color flower is the most abundant to feed on.

So far, research has shown they can remember these flowers for a few days at a time and will keep returning to them. If they perceive predators along their established routes, they may choose a different path or find new flowers.

The bee has the butterfly beat in memory, it too can remember which flowers it visited and in relation to distance from the hive.

Bees also are taught at a young age how to do their job in the hive, showing the bee has a memory to work from.

As bees do live as a community, having to work together means having to remember what others need to accomplish the goal. 

2. Ego

Ego is the perception or sense of self that a person possesses about him/herself. Studies now show that insects also have an ego. 

An insect’s ego is very different from a human. We may have an ego that crops up and colors our behavior regardless of the circumstance and persists through a majority of our existence.

An insect, on the other hand, is egocentric only about what is relevant in the present moment. This is due to the midbrain we previously discussed. 

An insect is concerned about a predator in its feeding location or coming home with food for the winter to find their home destroyed. Quite simply, the concern is about survival – first and last.

Therefore, we must look at ego in insects carefully. Ego as humans know includes narcissism, insects are not at that level.

This can be explained by the example of ants. This is a community of many working parts, if a handful of ants became egocentric the way humans understand, the system would not work.

Because ants can work together for the good of all, they are not considered to have an ego; yet if there is an intruder the ant is egocentric in the way that he understands all his work could be for nothing. That’s devastating for the ant.

Researchers agree that insects do have a rudimentary ego. However, that ego is used to focus on what is important to them. Insects use their midbrain, same as us, to trigger a basic capacity for subjective experience.

That experience is then used to help the insect ignore other impulses and/or stimuli and hone in on a task at hand that allows them to fully participate and execute tasks that end up advancing their interests and helping their group and species to survive.

3. Emotion

An excellent example of an insect with emotion would be the common fly. The fly can feel fear and remember it, especially when a traumatic event happens close to their food source.

One study by William Gibson (Post-Doctoral, Caltech) found that flies feel fear similarly to humans. Using overhead shadows as the flies flew to their food, he found that they would display behaviors like other animals.

Some flies would speed up their pace, while others would freeze in place. Over time, with more shadows, the flies would take longer to return to that food source. 

Emotion is essential for survival, understanding danger, feeling fear, and responding to it, matter. Therefore, emotion is relevant to intelligence as it is a source of what one must do next to remain safe.

If flies can feel fear, they may be able to feel other emotions as well. This is a rather new topic being researched in insects, but to understand that a fly can feel fear could help humans to understand how to better deal with our own trepidations.

4. Communication

Teamwork takes effort and communication. Bees have a particular way of communicating to their hive mates, using the “waggle dance”.

This form of language allows the bees to tell each other where the pollen is, exactly. The message spreads to each individual bee that needs to know.

Communication is seen as a form of intelligence because such a facility is necessary to achieve a common goal. 

Another example in this regard are ants. Depending on the species, ants can use pheromones, touch, body language and/or sound to speak to each other.

They communicate anything they need to, from the location of new food to passing on the message if a butterfly is calling for help.

Along those lines, here is another interesting fact. Butterflies will call out to nearby ants for help if they find a predator to be nearby.

Under any definition, the ability to communicate to another species in order to work together cooperatively is rather smart.

5. Recognition

Recognition is important to intelligence as it pertains to the ability to know who can be trusted; thus aiding in survival. 

Wasps are intriguing in this regard. They have unique stripes and markings that are distinguishing features, similar to human fingerprints.

When one wasp returns to the nest, he may be met with aggression at first. However, scientists believe that the colony eventually remembers his scent, as evidenced by the fact that the painted wasp is rarely kicked out.

Wasps maintain a hierarchy, further establishing that they rely on signs of recognition. The wasps with lesser stature will even lower their antennae in respect to those above them. 

Insects that live more solitary existences, such as beetles and cockroaches, can communicate with their own species but do not seem to care who is who.

This does not make them unintelligent, though. Given their specific lifestyles, recognition in terms of recognizing their peers isn’t as important for them to survive. 

For those insects in communities such as bees and ants, recognition amongst themselves leads to better teamwork and also the ability to perform tasks according to an established hierarchy.

6. Problem Solving

When problem solving is concerned, there are a multitude of possibilities. A single person can be solving a problem, or a group of research scientists could do the same for a doctoral thesis or a development project.

Perhaps it’s a corporate team that is working in tandem, under directions from an overseer.

In the case of insects, planning and communication are harder for us to discern. However, researchers have traced specific instances of how insects use collective intelligence to solve problems that arise in their everyday lives.

Ants are great at finding the shortest path to and back from food (think your picnic basket or crumbs) or charting out paths between their nests.

Many times, the individual species are not known as being particularly intelligent, but there is a collective “swam intelligence” that prevails. Bottom line, ants are very good at sharing intelligence with each other. 

As an example, the invasive Argentine ants communicate with each other by tapping their stomachs on the ground to release pheromones which lay out a trail for others.

The reason this is important is that Argentine ants are not considered smart, but somehow they always seem to solve the shortest-path problems as a group even when they are not very good at solving problems individually.

7. Decision Making

Ther are many studies demonstrating how insects are capable of processing information and making decisions.

For example, an American Scientist article depicts how apple flies perform on virtual reality studies that provide insights on how they process stimuli and make decisions. 

The results show that the files respond definitively to a visual world that can not present visuals, wind and odors on a 360 degree basis, and can change based on how flies perceive their surroundings as they flap their wings and further penetrate into the environment.

8. Quick and Prompt Reaction

There are plenty of studies that show that insects are capable of quick and prompt reactions

9. Awareness

The concept of awareness in insects has been debated between various parties.

There are studies that show insects have self-awareness, consciousness and ego, and there are other scientific views that reject such concepts – often citing the fact that insect brains have a million or so neurons, compared with the human average of 86 billion.

According to this view, insects are “dark inside”, mainly being led by a collection of reflexes. 

With further research, scientists have begun to focus on not just the human neocortex, an extremely impressive and complex organ, but also on our more primitive midbrain – the simpler structure that helps synthesize sensory data into a unified, egocentric point of view that steers us right as we navigate the world.

Researchers from Macquerie University, following through on the above basis, argue that insects have midbrain-like structures with a “central complex”.

This central complex seems to allow bugs to model themselves as they move through space in their lives.

Evidence cited includes what they found from fly brain activity, as well as some macabre research that shows that cockroaches that get venom injected into their central cortexes by jewel wasps allow themselves to be led by the antennae into their predator’s lair.

In Conclusion … What’s the Verdict?

Insects do not have a brain similar to us humans. They simply do not need something as complex to survive and evolve.

On the other hand, when we look at some of the specific characteristics of how we define “brainiac” behavior, we find plenty of evidence that even with their rudimentary systems, insects demonstrate singular or collective behavior that shows clear evidence of brain activity that cannot be ignored.

All things considered, insects definitely seem to demonstrate the ability to perform tasks and otherwise behave in ways that would be aligned with brain functions above and beyond just a “collection of reflexes”. 

Alright, that’s it for this article, here are a few hand-selected articles that you might also find interesting reads:

Do Spiders Always Have Eight Legs? The Curious Answer

Do Insects Feel Pain? The Deep Dive Answer

Do Ants Hibernate in the Winter? Let’s Find Out