Insects cognition brain size and structure

Question 1

Describe the cognition of insects.

Answer 1

• Show some sophisticated cognition.
• Effective and distributed cognitive decisions: their decisions are not random.
• Group cognition is present: one insect acts one neuron within a group.
• No social learning.

Question 2

Describe the life history and ecology of insects.

Answer 2

• Short life span (varies between species but is typically a few weeks).
• Take up at least 20% of the Earths biomass.
• Have small brains.

Question 3

Describe the main structure of the insect brain.

Answer 3

Mushroom bodies

• Groups of neurons up to x15 more densely packed than mammals.
• Often multimodal and receive many different inputs.
• Interpret information from the environment.

Question 4

What is the function of the mushroom body?

Answer 4

• Associated with more developed cognitive and social functions.
• Integrate and process information from different senses.

Question 5

What is the evolution of the mushroom body like?

Answer 5

• Has evolved independently across different groups of insects, e.g. cockroaches are different to bees.
• Some are non-multimodal, e.g. Drosophila.
• Evolution has occurred due to demands of the social group/spatial behaviour/navigation, e.g. there is safety in numbers so evolution has occurred to allow for that.

Question 6

Describe the brain of a honeybee.

Answer 6

• Approx 950,000 neurons.
• The mushroom bodies make up half of the brain volume. These are made up of Kenyon cells (type of neuron) and associated fibres.
• There are small fibres and a high density packing.

Question 7

What are the 2 forms of cognition seen in insects?

Answer 7

Individual and collective.

Question 8

What is an example of collective cognition in bees?

Answer 8

When scouting for nest locations.

• Scout bees make up approx 5% of the swarm. These are the bees that leave the colony and assess potential locations.
• The swarm must make a rapid, collective decision on the location of their colony.

Question 9

How do bees decide what site to relocate to?

Answer 9

They make a consensus decision. This is based off the waggle dance.

• Scout bees come back and do a waggle dance - this is a navigational resource which tells the other bees where to go.
• As more scout bees come back, there is usually a winning waggle dance, and that leads to the chosen site.

Question 10

How is the swarm comparable to neurons in a brain?

Answer 10

• Individual scouts are sensory neurons.

- Waggle dance is a neuron firing.

Question 11

How does the swarm decide that the waggle dance is leading them to the best site?

Answer 11

More recruited scouts follow the waggle dance and look at the site for themselves. Only if they like it will they join in with the dance.

Question 12

What happens if a consensus is not reached?

Answer 12

e. g. if 2 nests have equally strong waggle dances.
- An inhibitory stop signal is deployed.
- This is a vibrational sound (150ms long) which causes the bees to stop doing the waggle dance.
- It is formed by 2 bees headbutting each other.
- It increases the reliability of the consensus decision.

Question 13

What are the phases of making a decision on nest site?

Answer 13

1. Piping - where the stop signals are deployed.
2. Implementation - where some bees are inhibited and a winner is emerging.
3. Decision - a winner is clear and a decision is made to go with this nest.

Question 14

Compare what happens when there is one possible nest site vs 2.

Answer 14

2 possible nest sites:

• Stop signals are deployed until bees from one group are reduced greatly.
• Decision is made once it is clear enough.
• The decision can be made even if the 2 competing groups are close.

1 possible nest site:

• There is less stimulation of the colony and less competition; piping phase is shorter.
• However, can still take a long time to make a decision .

Question 15

When do ants display collective cognition?

Answer 15

When searching for new colonies.

- This is done via forward tandem running.

Question 16

What is forward tandem running and in which insect is it seen in?

Answer 16

It is where scouts train other ants to become scouts. It is only seen in ants.

• Scout ants go out to look for colonies.
• The scouts train other ants to be scouts.
• Learned routes are followed by the trainee and then they lead other ants to the colony.
• When the quorum threshold in the new colony is reached, ants stop moving over.
• Both old and new colonies are functional.

Question 17

When else is tandem running seen in ants?

Answer 17

When finding food.

Question 18

How do ants behave as teachers when finding food?

Answer 18

Ants train follower ants even if it means that they miss out on food. This leads to an increase in overall food intake.

• The teacher slows down up to 4x.
• The teacher stops and waits while the follower is learning the route (by practising).

Question 19

Is teaching seen in bees?

Answer 19

No, only ants.

Question 20

What are the 6 types of individual cognition shown by insects?

Answer 20

• Configural.
• Contextual.
• Categorisation.
• Delayed match or non-match to sample.
• Using map-like information.
• Communication about an absent stimuli (abstract reasoning).

Question 21

What is configural cognition? Example

Answer 21

Knowing that different stimuli combinations give different rewards.
- e.g. if bees wait longer for a flower to refill nectar, they will get more food.

Question 22

What is contextual cognition? Example

Answer 22

Adapting their response to the stimuli based on the context.

- e.g. ants and bees show different behaviour when searching for a new colony or food.

Question 23

What is categorisation cognition? Example

Answer 23

Recognising different stimuli and responding differently.

- e.g. finding food.

Question 24

What is delayed match/non-match to sample cognition? Example

Answer 24

This is using memory to complete tasks.

- e.g. finding flowers with nectar in bees and finding food in ants.

Question 25

What is abstract reasoning? Example

Answer 25

Carrying out tasks when the stimuli or object is absent.

- e.g. scouts explaining the new colony to the swarm.

Question 26

How was it tested if bees use abstract concepts individually?

Answer 26

Their ability to recognise if something is above or below a bar was tested.
- This was done in a Y maze.

The bees were trained to go either above or below the bar with use of a reward.

• It was seen that once the bees went to where the reward was during training, the following bees went to the same place much faster.
• This shows contextualisation and imagination.

Question 27

How was the flexibility of bees behaviour tested?

Question 28

How was the flexibility of bees behaviour tested?

Answer 28

A novel problem which they don’t have an adaptation for was presented.

• The bees were trained to move balls to a target.
• Showed flexibility as they knew that the ball didn’t have to be a specific colour to get the reward.

Question 29

Why can insects be referred to as superorganisms?

Answer 29

They show cognition individually as well as through interactions with a group.

Question 30

What is colony level cognition?

Answer 30

Making decisions based on what is best for the colony.

- This is done by evaluating information and boosting/inhibiting signals until the threshold is reached.

Question 31

How are insects able to vary their behaviour?

Answer 31

The threshold for decisions is able to be varied.

- Allows quick inaccurate decisions, and slow accurate decisions.