1. Neuronal and hormonal control of behaviour
BIOL 3100

2. Why is this bee making sweet lovin’ to John Alcock’s thumb?

3. Tinbergen noticed that chick feeding behaviour in gulls is highly ritualized.
- chicks peck at the red dot on the gull’s bill
- parents regurgitate food
- chicks get fed
The question is: How close must the stimulus be to initiate the begging behaviour?
video

4. Model of gull head without dot
Cardboard cutout
Fake bill – stick with contrasting bars at the end
Model of bill alone

5. Sign stimulus (releaser): a signal from one individual to another
Sensory messages from the releaser are processed by innate releasing mechanisms (neuronal clusters) higher in the nervous system
Fixed action pattern: A pre-programmed series of movements that constitute an adaptive reaction to the releasing stimulus

6. Tinbergen’s Geese Video
Greylag geese will automatically scoop and retreive eggs that roll <1m from the nest
However, will also roll back anything roughly resembling an egg
If the egg is removed while the goose is in the process of rolling it back, the action will continue
Video

7. FAPs can be exploited...

8. FAPs can be exploited….
video

9. FAPs can be exploited...
Tongue orchids mimic the pheremone by Lissopimpla excelsa wasps Wasps land on the flower, expecting to find a mate, but instead find a flower structure that looks like a female wasp – which is close enough for the male wasp Pollen is then stuck to the wasp and transferred to the next tongue orchid

10. FAPs can be exploited...
Alcon butterfly larvae smell almost exactly like the larvae of two ant species (Myrmica rubra, and M. ruginodis). Ant workers will retreive the butterfly larvae and bring them back to the next, where the other workers will feed and protect the butterfly.
Not surprisingly, the story gets more complicated...

11. What are the neural mechanisms that underlie Fixed Action Patterns?

12. The use of ultrasound by bats wasn’t discovered until the 1930s
Donald Griffin suggested bats may use ultasonic echoes to detect prey
Designed an experiment where he hung prey were hung on strings in a room with obstacles all around a dark room
When loud sounds were played, bats navigated perfectly
When bombarded with ultrasound, bats began to collide with obstacles and crash to the floor, until the sound was turned off.
Kenneth Roeder realized that moths may also be able to hear in the same frequency of bats to avoid being eaten

13. Noctuid moths have two ears, one on each side of the thorax
Each ear has a thin cuticle, or tympanum lying over a chamber on the side of the thorax
Two neurons (A1 and A2) are attached to the tympanum, which are deformed when the sound pressure waves hit the moth (and hence the tympanum)
A1 and A2 receptors work like neurons – respond to energy in stimuli by changing the permeability of their cell membranes to positively charged ions
For moths, movement of the tympanum is the stimulus, which mechanically stimulates the receptor cell

14. Once channels in the cell membrane are opened, positively charged ions flow in, changing the charge inside the cell relative to the outside
If the movement of ions is large enough, an abrupt local change in the electrical charge difference across the membrane occurs and spreads to neighboring portions of the membrane sweeping around the cell and down the axon, creating an action potential – the signal that one neuron uses to communicate with another neuron

15. A1 is sensitive to ultrasounds of low-med intensity; A2 produces action potentials only when ultrasound is loud
As sound increases, A1 fires more often, with shorter delays
A1 fires more frequently in response to pulses of sound than steady sound
Response of both A1 and A2 is the same over a broad ultrasound range
No response to low-frequency sounds that we can hear

16. How moths locate bats in space
When the bat is to one side of the moth, A1 on the side closer to the predator fires sooner and more often than the shielded A1 in the other ear
When the bat is above the moth, A1 fluctuates synchronously with wing beats
When the bat is behind the moth, both A1 receptors fire at the same rate and time

17. Normally, a praying mantis holds is forelegs close to the body (top left), but when it detects ultrasound, it extends its forelegs (bottom left), causing it to loop and dive down. Lacewings (right) also use an anti-interception dive when detecting ultrasound
Video

18. Moths can do more than just evade

19. Tiger moths produce ultrasonic clicks in response to attacking bats
Experiment
Trained 3 juvenille and 1 adult big brown bat to capture tethered moths in a flight room
On each of the 9 consecutive nights presented:
4 tiger moths
4 tiger moths that were silenced (damage to sound-producing organ)
8 wax moths, which do not emit ultrasonic clicks

20. If the clicks act as a warning signal (venemous, unpalatable), bats should capture moths then drop them, then later abort attacks
If bats are startled, they should habituate
If clicks are a jamming defense, they should deter bat attacks when emitted, but that’s it

21. Bats contacted wax moths 400% more often than clicking tiger moths
Tiger moths without clicks were eaten each time they were encountered
Contact rates with clicking moths did not change throughout the experiment (thus, no learning or habituation)

22. Usually when brown bats capture prey:
1) approaches the target
2) increases frequency and amplitude of echolocation signals
3) captures prey
Video footage shows that clicks led to unusual echolocating behaviour.