Behavioral Neuroscience (Bats and Electric Fish)

Question 1

Two main bat groups (chiroptera)

Answer 1

Microchiroptera (microbats)

Megachiroptera (megabats)

Question 2

Two types of formes

Answer 2

Pteropodiformes

Vespetillioniformes

Question 3

From the two groups which is capable of laryngeal echolocation?

Answer 3

Microchiroptera (yangochiroptera)

Question 4

How did bats evolve?

Answer 4

interdigital webbing hypothesis: the ancestral bat exhibited interdigital webbing prior to powered flight ability

Powered flight may have evolved multiple times within the chiroptera- convergence

Yangochiroptera, Pteropodidae, and Rhinolophoidea evolved parallel trajectories from this common ancestor.

Question 5

What was the role of flight and active

echolocation during evolution?

Answer 5

Prey detection and identification in the dark
allows them to have different foraging habits- open spaces or dense vegetation

flight an ecolocation inextrcably linked

Question 6

What are bat wing characteristics?

Answer 6

strong but fine and delicate bones
reduction of ulna and carpals (maneuverability)
fusion of cranial bones (bird-like)
sesamoids- bone embedded in tendon

Question 7

Bat life cycle

Answer 7

Spring born
summer they brood and grow
fall reproduce
winter hibernate

Question 8

How do bats adjust their foraging strategies to urban environments?

Answer 8

Urban bats more exploratory: visit more sites per hour and switch foraging sites
diversified their diet
many bats roost in countryside but commute to forage in urban environments

Question 9

special bat diets:

Answer 9

fish
frog
mammals (small rodents)
blood licking

Question 10

What is active echolocation used for?

Are bats the only ones to use it?

Answer 10

Orientation and Prey detection

No, flying foxes
cave swiftlets
oilbirds
dolphins and whales

Question 11

How do birds echolocate?

Answer 11

click-type Biosonar signals

syrinx, the vocal organ specific to birds and found near to where the trachea forks into the lungs.

Birds use their syringes to produce broadband click-type biosonar signals that allow them to nest in dark caves and tunnels

echolocation found in at least 16 species- evolved convergently

Question 12

Types of echolocation

Answer 12

CF-FM signals - hunt in dense vegetation-single frequency, then dip

FM signals- hunts in open space- extensive range of frequencies

Question 13

What can be recognized from echolocation?

Answer 13

Distance: time btwn call and echo
Velocity
Flutter information
Size of prey
Horizontal localization
vertical localization
surface structure - (temporal and spectral structure of echoes)

Question 14

How does echolocation influence foraging behavior

and habitat use?

Answer 14

Bats in open and edge spaces - aerial hawking - detect localize prey by evaluating pulse-echo trains , prey echo is unmasked

Bats in narrow space - solve pattern recognition task - flutter detecting strategy and/or active gleaning and/or passive gleaning strategy

Question 15

How are bat ears different?

Answer 15

typical mammalian ear with some specializations

CF-FM (bats dense vegetation) high frequency slightly above end of spiral

Question 16

How can moths respond to foraging pressure by bats? What is

the ‘evolutionary arms race’ between bats and moths?

Answer 16

Insects can:
Avoidance behaviors:
fly away, diving, turning, zigzag
Produce ultrasonic clicks
Isolate from spaces where bats live

Bats in response
Shift frequency range
reduce intensity of emitted sound
cease echolocation and use passive hearing

Question 17

What are the ampullae of Lorenzini?

Answer 17

electroreceptor organs

Question 18

Which animals are capable of electro sensing?

Answer 18

Some amphibia
osteichthyes
chrondrichthyes
agnatha
bees are also capable of electroreception
mammals like platypus, echidna, dolphins

Question 19

How do bees electro recept?

Answer 19

detect by deflections of many tiny filiform hairs on head and body

bees are positively charges, flowers negatively

Question 20

How do mammals electro-recept?

Answer 20

They have specialized mucus gland electroreceptors (monotremes: platypus and echidna)

Dolphins have vibrissal crypts on the rostrum

Question 21

What are types of electroreceptors?

Answer 21

ampullae of Lorenzini
modified mucus electroreceptors
modified vibrissal crypt electroreceptors

Question 22

How do freshwater sawfish and shovelnose rays detect

natural electric fields?

Answer 22

in aquatic environments organisms emit weak dipole electric fields

They use ampulla of lorenzini

The elongation of the sawfish’s rostrum clearly expanded their electroreceptive search area into the water column and enables them to target free-swimming prey.

Question 23

How are electric fields used?

Answer 23

Finding prey
mates
environmental navigation

Question 24

How are natural electric fields created?

Answer 24

muscle potential of animals
potentials from wounded animals
potentials from body openings
potentials from gills of aquatic animals

Question 25

How can gene duplication contribute to electric organ evolution?

Answer 25

independently gained myogenic electric organs underlying electrical communication

voltage-gated sodium channel gene (Scn4aa), which arose by whole-genome duplication, was neofunctionalized for expression in electric organ and subsequently experienced strong positive selection.

Question 26

What are the two types of electric signals?

Answer 26

Pulse and wave

Question 27

What is an EOD?

Answer 27

Electric Organ Discharge

Question 28

Are weakly electric fish diurnal?

Answer 28

NOOO! Nocturnal

Question 29

What is a Mormyromast?

Answer 29

A tuberous receptor organ
for active electrolocation
perceive own EOD

Question 30

What is a Knollenorgan?

Answer 30

A receptor organ
for electro-communication
perceive others EOD

Question 31

How can predation and crypsis contribute to the evolution of

electric signals?

Answer 31

EODs can attract electroreceptive predators such as catfishes and electric eels
Weakly electric fish respond by shifting either high or low with masking signals
females and subadults emit no low frequency energy
males in areas of high predation emit few low energy signals-expressing their signals in less risky ways
these changes can be costly but have provided basis for subsequent selection and to differentiate between species.

Question 32

What are IDIs?

Answer 32

Inter-discharge interval

behavioral state and motivation

Question 33

What can weakly electric fish perceive during active electrolocation?

Answer 33

Objects are detected by - electric images which project onto the animal’s electroreceptive skin surface.

resistive and capacitive components of an object’s complex impedance

distance
3D shape of objects

Question 34

What can weakly electric fish perceive during active electrolocation?

Answer 34

Objects are detected by - electric images which project onto the animal’s electroreceptive skin surface.

can distinguish between resistive (how hard it is for an electric current to flow) and capacitive objects (amount of charges an object w/o discharging)

 peak amplitude, 
maximal slope, 
image width, and waveform distortions. 
distance
3D shape of objects

Question 35

How do weakly electric fish detect capacitance?

Answer 35

A cells respond to amplitude changes
B cells respond to amplitude and waveform
both inputs are compared in the brain

Question 36

How do fish quickly identify prey items?

Answer 36

concept of electric color