VL 4

Question 1

What is sensory ecology?

Answer 1

Sensory ecology is the study of how organisms obtain, process and respond to information from their environments

Question 2

What is a proximate cause?

Answer 2

An immediate underlying cause based on the particular features of an individual organism and its environmet

Question 3

What is an ultimate cause?

Answer 3

The evolutionary, historical reason why the insect is the way it is and has a particulat set of behaviors

Question 4

two types of directed response to a stimulus

Answer 4

Endogenous: arisin gfrom within

Exogenous: arising from the external

Question 5

Innate or inheritedd behaviour

Answer 5

consist of more or less predictable, genetically programmed responses (or sequences of responses) to different types of stimuli

Question 6

Learned behavior

Answer 6

Behavior that is acquired as a result of the experience of an individual

Question 7

Orientation Behavior

Answer 7

Processes that an insect uses to organize its behavior with respect to spatial features of the environment

Primary (positional) orientation: Body position, posture control, e.g. dorsal light reaction

Secondary orientation: translational processes: kinesis, taxis (movement)

Question 8

Primary Orientation

Answer 8

The dorsal light reaction

Dragonflies maintain their vertical orientation by turning their bodies until the immatidia of the two eyes are equally illuminated

Important in flight

Backswimmers (notonecta) have a ventral light reaction

Question 9

Secondary Orientation

Answer 9

Kinesis: random or undirected locomotor reaction in which the speed of movement or the frequency of turning depends on the intensity of stimulation

Taxis: non-random movements directed toward or away from a source of stimulation

Question 10

How can Kineses be classified?

Answer 10

By type of Stimulus
Hygrokinesis: to humidity or moisture
Photokinesis: to light
Stereokinsesis: to contact with surfaces
Chemokinesis: to a chemical gradient

By type of movement
Orthokinesis: speed of movement depends on stimulus intensity
Klinokinesis: frequency of turning depends on stimulus intensity

Kinesis allow th einsect to randomly search the environment but to slow down or stop moving when it encounters desirable conditions

Question 11

Taxis

Answer 11

A movement of orientation in response to a source of stimulation

positive: if orientation is toward the stimulus source

negative: if orientation is away from the stimulus source

Question 12

Phototaxis

Answer 12

Negative phototaxis - movement away from a light source

Positive Phototaxis - movement toward a light source

Question 13

Why do moths move towards light sources?

Answer 13

Moths use the moon as positional indicator in order to maintain bee-line flight at night

Lamps are mistaken by moths to be no more than small moons

moths fly round and round a lamp, at each turn getting a bit closer to it

Question 14

Menotaxis
Astrotaxis

Answer 14

Menotaxis: Constant angle to stimulus

Astrotaxis: Sun or moon (can take into account movement of light source - navigation)

Question 15

Phonotaxis

Answer 15

oriented movement of an organism with respect to a sound

Female cicadas orient to the sounds made by male cicadas who have special vibrationg structures, tymbals on their abdomen

Question 16

Rheotaxis

Answer 16

Aquatic insects often orient themselves with respect to a water current; this is rheotaxis

For instance, a black fly larva will situate itself where the current is fastest, so that it can capture the maximal of floating detritus in its labral fans

Question 17

Chemotaxis

Answer 17

Odors also provide a cue for insect movement

In a typical scenario, insects reorient their direction of movement toward something that smells attractive

Question 18

Overview over different taxes

Answer 18

Phototaxis: light
Chemotaxis: chemical oor
Phonotaxis: sound
Rheotaxis: water current
Thermotaxis: temperature
Skototaxis: darkness

Question 19

What factors can influence a basis taxis?

Answer 19

Below 16°C honey bees are negatively phototactic, above 16°C their response is positive

Ips (Coleoptera) are positively phototactic when flying. When feeding their response is negative

Taxes can be influenced by the physiological state of the insect (hunger, mating condition)

Question 20

Types of learning behavior

Answer 20

Avoidance behavior - avoid negative stimulus

Habituation - prolonged exposure to stimulus lead to an eventual loss of response

Conditioning - capacity to associate a stimulus with a reward or punishment

Locality learning - learning the position of food or nest; “homing” behavior (e.g. Ammophila, honeybees)

Question 21

Preimaginal conditioning

Answer 21

Carry over of learned information from an immature to the adult stage. Most common with feeding behaviors, involving inducible preferences

Question 22

Chemical ecology

Answer 22

Chemical ecology explores the role of chemistry in mediating interactions among organisms and between organisms and their environments

Question 23

What do organisms use chemicals for?

Answer 23

Lure their mates
Associate with symbionts
deter enemies
fend off pathogens

Question 24

Semiochemicals: Infochemicals

Answer 24

Pheromones: within species
Allelochemicals: between species

Question 25

Types of Allelochemicals

Answer 25

Synomones: Sender + Receiver +
e.g. Floral scents attracting pollinatiors

Kairomones: Sender- Receiver +
e.g. Plant feeding stimulants

Allomones: Sender+ Receiver-
e.g. Plant & insect defensive chemicals (repellents, plant toxins)

Question 26

What is a Pheromone?

Answer 26

defined chemical signal between members of the same species, eliciting a particular behavior or physiological change

broader definition:
any chemical signal conveying information between members of the same species

Question 27

When are Pheromones used?

Answer 27

Mate choice
Sexual maturation
successful fertilization (aquatic animals)
Kin Recognition
Caste and reproductive status (social animals)
maternal-infant bonding
dominance hierarchy
aggression
territory and trail marking
deception (plant -> animal)
Deception (animal -> animal)
Aggregation
intruder alarm

Question 28

Sex pheromones

Answer 28

Readiness to mate
attraction pheromones: long distance to attract mates

Previous to mating
emitted by males and/or females at a short distance/high concentration persuade females/males to mate

After mating: defence of reproductive investment
dissuades rival males from mating with the same female
e.g. Benzyl cyanide in P. brassicae transferred during copulation

Question 29

Alarm pheromones

Answer 29

released in response to predator attack

e.g. Aphid alarm pheromone (E)-beta-farnesene
causes aphid dispersion: walking away or dropping from the plant
Plants also produce (E)-beta-Farnesene, it disappears within about 10 min

Question 30

Pheromones in social insects

Answer 30

nestmate recognition

trail-following & recruitment: foraging for food

Caste determination

territorial

Question 31

Primer pheromones

Answer 31

physiologically active
change in insect development
slow onsetg
long persistence

Question 32

Releaser pheromones

Answer 32

Behaviorally active
Rapid response
Quick degradation

Question 33

Aggregation pehromones

Answer 33

mate finding & mass attack

aggregation pheromones used to control stored product insects

Question 34

mimicry

Answer 34

pheromines subverted for deception

Question 35

What are the problems?

Answer 35

Making chemical signals that convey information and broadcast/distribute them

Detecting & discriminating signals among the noise

Responding to signals quickly and learly and making the right decisions

Question 36

Sex pheromones in crop protection

Answer 36

Pheromone traps
wide-area mating disruption
Sex pheromone become ubiquitous, thus males are confused & not able to find female

Question 37

Allelochemicals

Answer 37

Chemcials that trigger a response in members of a different species

Mediate vital insect behaviors

• host habitat discrimination
• host detection
• host recognition & acceptance
• Feeding behavior: stimulants or deterrents
• social interactions

Question 39

Allelochemicals - Host detection, finding, recognition & acceptance

Answer 39

olfaction: smell (detections of odors-long & short range

taste: contact chemoreception (detection of chemicals in solid or liquid form - short range)

Question 40

Allelochemicals - Insect chemical defence

Answer 40

Sequestration = acquisition of toxic chemicals from foods consumed by an insect

More than 43 spp. of insects are known to sequester chemicals: grasshoppers, aphids, beetles, wasps, butterflies & moths
True ssequestration requires the toxic to be systematically translocated from the gut to other body tissues

See example on page 57, monarch butterfly