Echolocation in Bats

Question 1

What suborder of bats mainly use echolocation?

Answer 1

Microchiroptera

Question 2

What suborder of bats use mainly visual perception?

Answer 2

Megachiroptera

Question 3

What genus of bats in Megachiroptera uses echolocation, and how is it different from ones in Microchiroptera?

Answer 3

Rousettus

create audible pulses by tongue clicking

Question 4

How is echolocation an important adaptation for bats?

Answer 4

1. Nocturnal insect catching abilities
2. Nocturnal fruit/nectar eating
3. Dominate aerial zone during darkness, to avoid clashing with birds

Question 5

Around what era was birds and bats known to divide their diel cycle?

Answer 5

Cenozoic era

Question 6

How are echolocation pusles created in Microchiropterans?

Answer 6

High intensity pulses produced in the larynx via cricothyroid muscles, then emitted through the mouth/nose

Question 7

Which families of Microchiropterans emit the highest intensity through their mouths?

Answer 7

Vespertilionids, Molossids, and Noctilionids

Question 8

Which family of Microchiropterans emits the highest intensity through their nose?

Answer 8

Rhinolophids (horseshoe bats)

Question 9

Which families of Microchiropterans emit low-intensity pulses (whispering bats)?

Answer 9

Nycteridae, Megadermatidae, and Phyllostomidae

Question 10

What types of food do high intensity & low-intensity bats eat?

Answer 10

High intensity bats = flying insects

Low intensity bats = fruits/nectar/small vertebrates/ground insects/vegetation

Question 11

What is the purpose of the horseshoe-like structure surrounding the nostrils of horseshoe bats?

Answer 11

Acts as a megaphone to concentrate short wavelength pulses emitted into a beam - thus detect/scan their environments

Question 12

Which inner muscles are extremely well developed in bats?

Answer 12

1. Tensor tympani (changes tension on tympanic membrane)

2. Stapedius (changes angle at which stapes contacts the oval window)

Question 13

What is the time difference between APs that activate cricothyroid muscles and inner ear muscles?

Answer 13

3 milliseconds

Question 14

What is an additional structural refinement of the ear?

Answer 14

Middle and inner ear are insulated from the rest of the skull

Question 15

How are the middle and inner ear insulated from the skull?

Answer 15

By blood-filled sinuses/fatty tissues

Question 16

What is the major advantage of using high frequencies?

Answer 16

A balance between prey size and wavelength of echolocation pulses (usually most efficient for detecting small-mid sized insects)

Question 17

What is the frequency range of ultrasonic pulse in bats?

Answer 17

210-20 kilohertz

Question 18

What is frequency modulation (FM)?

Answer 18

Change in frequency according to the modulating signal, but amplitude remains constant

Question 19

How are some nocturnal moths adapted against the predation of bats?

Answer 19

Contain an ear on each side of the rear part of the thorax - each is a small cavity with a transparent membrane, that detects ultrasonic pulses of foraging bats

This allows them to alter their flight level and adopt various erratic flight patterns

Question 20

What families of moths have sensitive cavities for detecting ultrasonic pulses of foraging bats?

Answer 20

Noctuidae, Ctenuchidae, Geometridae, Arctiidae

Question 21

How do some bats remain inconspicuous to moths during foraging?

Answer 21

1. eg Megadermatids - listen for sounds made by prey instead of using echolocation
2. eg Australiana insectivorous bats use frequencies that partially avoid detection of moths