Locust phase change

Question 1

When does locust aggregation occur?

Answer 1

When food is scarce

Question 2

What happens in the gregarious phase?

Answer 2

Locust crowding
Locusts are no longer repelled by each other
More active
Develop warning colours
Awake during the day
They feed on toxic plants to suppost their warning colours

Question 3

What do locusts use to smell?

Answer 3

Their antennae

Question 4

What can cause gregarisation?

Answer 4

Sight/smell of other locusts
Presence of other locusts
Hind leg touch (outside of the femur)

Question 5

What is the DCMD?

Answer 5

Descending Contralateral Movement Detector
A large visual inter-neuron that responds to looming objects. As the object increases in size in the eye this neuron increases firing
In the solitarious phase it habituates much more rapidly

Question 6

What are the consequences of aversive odour learning in the different phases?

Answer 6

When given the choice between poisonous vanilla and lemon:
Solitary phase locusts begin with vanilla but quickly switch to lemon
Gregarious phase choose lemon for a significant amount of time before switching to lemon. This is because their taste-testing ability is off and instead they use post-ingestive feedback so they don’t know to switch until after the food has had a negative effect on the body. Toxic intake is monitored
Newly gregarised stick with vanilla as their taste and post-ingestive feedback are both off because they need to compensate for their lack of warning colours