Cricket Sound

Question 1

How does the cabbage moth caterpillar process sound? Why is it important for their survival?

Answer 1

• wasps lay eggs on caterpilars
• caterpillars detect sound with 4 hairs
• they will drop if the sound has a large amplitude otherwise they will stay still
• must detect sound through displacement because female wasp beats her wings at 150 hz with a wavelength of about 2m making pressure the same on both sides

Question 2

How do crickets sing?

Answer 2

• wings have a file with rigid teeth and a scraper
• one complete closure of wings equals a pulse or syllable
• use M99 to open and M90 to close

Question 3

What is the carrier frequency?

Answer 3

• how long it takes the wings to close and do one stroke

Question 4

Where are the cricket’s ears located and what are their structure?

Answer 4

• located at elbows of front legs
• have a posterior and anterior tympanum
• ears are connected by a series of tracheal tubes

Question 5

How do crickets differentiate sounds to avoid hybridization?

Answer 5

• they respond to a specific carrier frequency ranging from 3-5 khz
• also respond to a specific rate (30 syllables per second)

Question 6

Why does the cricket zigzag to track the sound?

Answer 6

• moves until she is perpendicular to the sound, as soon as she goes past perpendicular she zags back
• at perpendicular she has ispilateral ear maximal displacement and hardly any input to the contralateral ear

Question 7

How does ipsilateral ear maximal displacement occur while the contralateral ear has hardly any input?

Answer 7

• the contralateral ear is receiving input from the outside and the inside, the distance traveled by both is about the same so the input occurs at the same time and cancels each other out
• for the maximal ear, pressure on the outside and inside are ‘out of sync’ meaning it is pulled and pushed in the same direction

Question 8

What does the auditory nerve do? Where does it travel?

Answer 8

• auditory nerve carries information from sensory neurons in ears up leg and terminates in auditory neuropil of prothoracic ganglion

Question 9

What are the omega neurons? How do they function?

Answer 9

• omega neurons are prominent auditory interneurons in prothoracic ganglion
• ‘copy’ song resulting in a burst of action potentials and simultaneously inhibit the contralateral side (reciprocal inhibition)
• sharpens sensitivity

Question 10

What are the ascending neurons? What do they do?

Answer 10

• ascending neurons receive excitatory input from the auditory receptors ad inhibitory input from the contralateral omega neurons
• copy song and are sensitive to 5khz frequency producing directional sensitivity
• involved in phototaxis

Question 11

Where do the brain neurons class 1 receive input from and how do they respond?

Answer 11

• BNC1 receive input from one of AN-1

- “low-pass” cells that respond to syllable rates of 30 syllables/s or below

Question 12

Where do the brain neurons class 2 receive input from and how do they respond?

Answer 12

• BNC2 receive input from one of BNC1, AN, or BNC2
• some respond as “band-pass” cells and respond to 30 syllables/s
• others respond as “high-pass” cells and respond to 30 syllables/s or more

Question 13

Specifically where does input come from to BNC band-pass cells?

Answer 13

• get input from “low-pass” BNC1 and “high-pass” BNC2

- “AND gate”: (coincidence detector) respond best to simultaneous input from both

Question 14

What were researchers able to find in the field and not in the lab?

Answer 14

• environment (grassland vs bushland) had an effect on the maximum hearing distance differing by about 20 m

Question 15

What interesting adaptation does the mole cricket have?

Answer 15

• have low frequency and high frequency neurons tuned to detect ultrasound
• avoid bat predation

Question 16

What interesting adaptation is seen in the cabbage moth?

Answer 16

• cabbage moth can detect ultrasound

- causes neurons that drive wings to stop firing or to doublet fire