Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Insect Ecology > VL 5 > Flashcards

VL 5 Flashcards

1
Q

Insect mouthpieces

A

Mandibles - chewing
Proboscis - piercing-sucking or siphoning Labelllum - sponging

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Feeding strategies - how are herbivores categorized

A

Feeding guild - how and where do they eat

Diet breadt - what do they eat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Feeding guilds

A

Where on the plant dies the insect feed?
- roots, stem, seeds, fruits, leaves
- exophage vs endophage

How does the insect feed?
- Mouthpart type? Chewing or sap feeding
- Gall inducing? Leaf rolling?

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Endophage

A

Feeds inside the plant, such as stem boreres, leaf miners or gall forming insects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Exophage

A

Feed on exposed locations such as leaves, flowers, pollen, seed heads
e.g. caterpillars, beetles and grasshoppers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Sap feeding

A

Needle-like mouthparts puncture plant tissue

Manly hemiptera (e.g. aphids)

Can transmit viruses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Diet breath categories

A

Monophagous: single plant species
Oliphagous: several species in the same family
Polyphagous: species in different families

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Coevolution

A

Two (or more) species which have reciprocally affected each other’s evolution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Speciation due to specialization on a specific host plant can be caused by:

A

Interspecific competition - niche food resource
Abundance of plant species
High offspring performance
defence against natural enemies
- toxins
- mimicry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Optimal defence hypothesis

A

Plant defences are costly, taking resources from growth and reproduction. Allocation of resources is therefore in relation to risk of attack, value of the plant tissue and the cost of the defence

Long lived and short lived plants, or plants of the same species in different environments, may invest differently

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Types of plant defences against herbivore attack

A

Nutritional constraints
Mechanical
Chemical
Indirect defences

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Nutritional constraints

A

Maintaining balance of C:N:P is essential for metabolism and cell function

Slow growth, high mortality hypothesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Counter adaptations for nutritional constraints

A

Manipulate nitrogen content
- N-rich sites
- Symbionts
- Life cycle sync
- Storage + excretion
- Nutrient sinks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Mechanical and structural defence

A

Toughness / hardness (dense cell wall or high silica content)

Waxy surface

Crypsis (camouflage) and Refuges

Spines and Trichomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Trichomes

A

Mechanical barriers to feeding or oviposition (non-glandular trichomes)

Produce silky substances or toxins that trap or harm herbivores (glandular trichomes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Counter defence - mechanical and structural

A

Hardness:
- morphology - larger/specialised mandibles. Extra molts to replace worn mandibles

Trichomes:
- Modified tarsal claws to grasp non-glandular trichomes
- No tarsi to avoid triggering glandular trichomes
- Long proboscis or chewing mouthparts

Waxy:
- Tarsal adaptations like clasping feet, hook structures, suction cups
- Behavioural strategies

17
Q

Chemical defence

A

Directly affect insect growth and development

May interfere with insect metabolsim - toxins such as pyrethroids or nicotine. These are cheaper for the plant to produce but lower effectiveness against co-evolved insects

Or can be indigestible or sticky, e.g. tannins, resins and latex. These larger compounds are more costly to produce, but offer better protection as they are difficulta to evolve tolerance for

18
Q

Chemical - constitutive and iduced

A

Plants may have constitutive (always present) and induced (produced when attacked by herbivores) defences

Constitutive = baseline protection before herbivores detected

Induced = high levels produced in affected tissues - targeted
Regulated by phytohormones jasmonic and salicylic acid

19
Q

Constitutive defence

A

Always present

Provide protection before attack detected

resource costly to grow / continuously maintain

Godd against generalists

E.g. spines, cellulose, alkaloids, trichomes, resins, tannins

20
Q

Induced defense

A

Activated by herbivore feeding

Temporarily costly, but only activated when needed

Plant takes damage before defence response

Targeted: Localised to affected tissue and may be specific to insect species

Regulated by phytohormones jasmonic and salicylic acid

E.g. Trichomes, Phenolics, Alkaloids, Natural enemies, Terpenoids, Digestive inhibitors

21
Q

Jasmonic acid

A

p. 27
Chewing herbivore damages plant
-> Local production of jasmonic acid
-> Plant produces volatiles to repel herbivores or attract natural enemies
or
Local production of toxins and digestive inhibitors
-> Generalists move to new part of plant / new plant
or
Specialsits counter

Alternate pathway: salicylic acid mainly involved in pathogen defence, but can also produce defences against sap feeding insects. Reduces defence against chewing herbivores
Mutually antagonistic: some insect (including generalist) can induce one pathway to shut down the other

22
Q

Chemical - priming

A

Plants receive volatile signals from neighboruing plants under herbivore attack

Priming effect allows activation of induced defence signaling pathways to ready them before herbivores arrive, giving fitness benefit. Priming acts like a vaccination, so that defence will trigger more quickly and strongly on herbivore attack

This can be used in pest management to increase defences against herbivores

23
Q

Chemical - counter defence

A

Detoxification enzymes
These can be included in the insect after consuming alkaloid rich food

Filtering and excretion - e.g. Manduca sexta moths eliminate nicotine with a specialized alkaloid transport system in Mlpighian tubules

Sequestration - specific and selective uptake and accumulation of plant toxins. The insect is then toxic to predators. Costly mechanism

Behavioursal deactivation ot avoidance - can deactivate latex / resin channels by clipping veins (common in milkweed plants), trenching or mass attack

24
Q

Indirect defences - natural enemies

A

Induced defence - volatile emissions triggered by feeding or oviposition will attract natural predators / parasitoids which will attack the herbivores - mutualism

25
Q

Indirect defences - natural enemies - counter defence

A

Some herbivores can suppress volatile emission to prevent natural enemies being recruited

26
Q

Indirect defences - predator rewards

A

Plants produce energy rich foods to attract predators of herbivores - extrafloral nectaries and protein bodies

May also have structures that act as domiciles for predators insects - do not attract predators but make it more likely visiting predators may remain

27
Q

Enemy free space

A

Insects under high predation / parasitoid pressure -> shift to new local plant -> lower enemy pressure

28
Q

Host-shifting theory

A

Herbivore fitness isadversely affected in the presence of enemies

Fitness is greater on a novel host in the presence of enemies

In the absence of predators, insects may still have greater fitness on the ancestral host

29
Q

Enemy free space

A

see slides 39 - 44

Insect Ecology (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions