During a conversation I was having with someone on insects, something I do a lot, we got into the topic of insect behaviour. One thing I remember from the conversation was them saying “you mean mosquitoes have a brain”? Yes, all insects have brains. In fact, they have more brains then we do (I’ll explain later what I mean by this). Some biologists have written articles dealing with what are the smartest insects. Defining what we mean by smart or intelligence can be a bit subjective, but it makes for good discussion. In this edition of Incredible Creatures we will explore what are some of the smartest insects.
Before discussing what are our smartest insects, it is helpful to take a walk through the basics of an insect’s brain, and be warned they are quite weird, not at all like us. The easiest way to understand an insect’s nervous system is that an insect has many different sub-brains in different parts of its body. These feed into and can be controlled by a slightly larger central brain but can actually also operate separately. The antennae of an insect has its own brain. So does each leg, the mouth and the eyes. Even if the central brain of an insect stops working, its legs still have their own sub-brains, and can keep walking.
Insects have, even considering their small size, a comparatively smaller central brain than we do, and with a very much smaller neural count. A bee has under a million neurons in its main brain. Humans have about a hundred billion. Whether the amount of neurons or the size of the brain is related to intelligence is not really clear. Researchers still don’t know what humans are doing with all those neurons. In an insect, the key thing is a pair of structures in the main brain called mushroom bodies that are responsible for learning, memory, and intelligence. Generally speaking, the larger the mushroom bodies, the smarter the insect.
There’s another thing to consider though when we speak of intelligence. It’s more complicated than saying “big brain equals big smarts.” Biologists studying insect behaviour claim that insects referred to as “generalists” tend to be the most intelligent. What they mean is that insects, and animals in general, demonstrate more intelligence when they are equipped to adapt to all kinds of food sources and habitats. An animal that only eats one kind of leaf in one kind of tree doesn’t have to have as highly functioning a brain as one that has multiple food sources. And needing to work with others takes the need for intelligence to a whole other level. So back to our original question: what are some of the smartest insects?
Social Insects are Smart Insects
There have been some interesting studies recently on various invertebrates demonstrating complex learning and memory. In a recently published study, shore crabs were able to learn the quickest way through a maze to get to a source of food (a crushed mussel), and remember this quickest route two weeks later when put through the same maze.
Crustaceans, such as crabs, have a brain roughly 10 times less than the size of a bee’s in terms of neuronal count. When it comes to studies on learning in insects, bees, ants and termites are three groups that tend to get special recognition. These three groups are what we refer to as social insects. They all live in colonies. They have to recognize nest mates, and communicate with them often. The challenges of living within a large community require intelligence.
One group that is very well studied is bees. Honey bees are able to recognize and distinguish between human faces. This is a surprising trait given that it’s not really necessary for their survival. And bees can count, at least to some degree. In an experiment, honey bees were rewarded for stopping at the third in a series of landmarks, and proved able to remember this location and to thus count. The distance was altered, while keeping the same number of landmarks, to discourage the bees from using their sense of distance.
Bees are capable of observation, learning, and memory to solve problems. When bees start going to different flowers, they initially have no knowledge about how good a source of nectar and pollen each provides. Through trial and error they can learn and remember which are good sources of food.
Bees can also learn new strategies for getting food from watching other bees. If a flower is difficult to get inside to get at the nectar, they may use a technique called nectar robbing. The bees figure out that it can be easier to bite a hole in the base of the flower to suck out the nectar rather than figuring out how to get inside the flower. It’s been shown that other bees are able to observe this strategy, understand its purpose, master it themselves, and remember it for future flowers. That’s pretty smart!
Communication Through Dance
There are a lot of other examples of learning, memory, and intelligence that I could discuss about bees, ants, termites, and many other insects. But that would be a book and not an article. So I am going to end with what I think is one of the most impressive examples of intelligence in insects, communication through dance. If you could not talk (say a bad bout of laryngitis) and were challenged to explain to someone how to get from your house to the grocery store through nothing but interpretive dance, how well do you think this would work?
Perhaps the best-known and most incredible bit of intelligence from honey bees is communicating flower location with special dances. There are two types of dances; the round dance, which a bee does to tell other bees there is food close to the hive (within about 100 metres or closer), and the waggle dance, which they will use to tell other bees about more distant food sources. In the round dance, after distributing some of her new-found nectar to waiting bees, the bee will dance in a circle, turn around, then dance the same circle in the other direction. The bee may repeat this several times.
The waggle dance is more complicated. It tells the bees that are watching two things about a flower patch: the distance and the direction away from the hive. Here’s how it works: to communicate distance from the hive the dancing bee waggles back and forth as she moves forward in a straight line. She then circles around to repeat the dance. Distance is indicated by the length of time it takes to make one circuit (longer to do a circuit for food further away). For example a bee may dance 8-9 circuits in 15 seconds for a food source 200 meters away, and 3 circuits in 15 seconds for a food source 2000 meters away.
But how is direction communicated through dance? Bees know which way is up and which way is down inside their hive, and they use this to show direction. Bees dance with the waggle at a specific angle away from straight up. The bees observe this angle, and once bees leave the hive the bees will look at the position of the sun, and fly at the same angle away from the sun as communicated in the waggle dance. For example, if the bee waggles while facing straight upward, than the food source may be found in the direction of the sun. If she waggles at an angle 60 degrees to the left of upward, the food source may be found 60 degrees to the left of the sun. This communication enables the bees to quickly mobilize a large number of foragers to gather nectar and pollen that may only be available for a short period of time.
Honey bees are capable of language, facial recognition, number use, observation and mimicry, the understanding of rules, and high-level problem-solving. How’s that for amazing. And there are other insects that we could easily make similar case for having amazing levels of intelligence.
One ecological publication makes the case, and is titled, “Every animal is the smartest”. After all, they all need the traits that help maximize their survival in the environment that they are living. Picking the smartest can be subjective. But even the smallest of insects do have brains (or more properly many brains). It’s amazing how much information and intelligence can come from even a tiny brain.
Incredible Creatures is a monthly contribution to provide information on some of the common yet often not well known creatures that we share space with in Manitoba and abroad.