Brainscape's Knowledge GenomeTM

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


See full index

Entomology > insect interactions - herbivory > Flashcards

insect interactions - herbivory Flashcards

1
Q

what is meant by the term ecosystem service

A

benefits from resources and processes which have been supplied by ecosystems

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

what is the UN2005 Millennium Ecosystem Assessment

A

an analysis of the state of Earths ecosystems and provides a summary and guidline for decision makers

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

list the ecosystem services which are split into four categories

A

1) provisioning
2) regulating
3) cultural
4) supporting

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

outline what is meant by the ecosystem service - provisioning

A

the production of food and water, raw material, medicinal resources and genetic resources

= products obtained from ecosystems

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

outline what is meant by the ecosystem service - Regulating

A

the control of climate and disease, purification of water, pollination, erosion and soil fertility, natural hazards regulation

= benefits obtained from regulation of ecosystem processes

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

outline what is meant by the ecosystem service - cultural

A

recreation and tourism, information and education, cultural heritage, mental wellbeing and aesthetic value

= non-material benefits obtained from ecosystems

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

outline what is meant by the ecosystem service - supporting

A

ecosystem process maintenance, biodiversity maintenance and protection, life cycle maintenance = underpins all other services

= services necessary for the production of all other ecosystem services e.g. primary production, soil formation and nutrient cycling

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

argued that time to put more effort into developing integrated research on the ecosystem services provided by insects as they may result in sustainable development goals
= provide evidence of ability to adress global challenges
= propose framework to shift perception of insects from enemies to allies and eventually soltions

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

what is an ecosystem function

A

something which maintains an ecosystem service including physiochemical and biological processes which occur in an ecosystem
= higher biodiversity stabilises and diversifies ecosystem functioning
= composition and diversity of functional traits which appear to be the best predictor of ecological processes

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

what is meant by a functional trait

A

morphological, physiological, phenological or behavioural characteristics of organisms which influence performance or fitness through effects on growth, reproduction and survival

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

outline how insects act as ecosystem service providers

A

they affect nutrient cycling both directly and indirectly
= reduce net primary production through herbivory and the breakdown of litter via detrivores
= important roles as ecosystem engineers
= indirectly –> may affect species composition

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

outline how insects can perform ecosystem functions via interactions with plants

A

interactions will have a signififcant effect on ecosystem functioning
= herbvivory and mutualisms (pollination)

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

give some examples of insect orders which are phytophagous (feed on plants)

A
  1. Orthoptera
  2. Phasmatodea
  3. Lepidoptera
  4. Coleoptera
  5. Thysanoptera
  6. Hemiptera
  7. Pscocoptera
  8. Hymenoptera
  9. Diptera
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

how are herbivorous insects categorised

A
  • diet breadth = host plant range
    = mono/oligo/polyphagous
  • feeding guild = chewers/sap feeders, free living/concealed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

outline the category of herbivorous insects which are free-living chewers

A

eat exposed plant parts such as leaves, flowers or seeds
= most numerous mandibulate insects are coleoptera and lepidoptera (larvae)
Orthoptera, Hymenoptera and Phasmatodea
are next numerous

17
Q

outline the category of herbivorous insects which are concealed chewers

A

include lepidoptera, coleoptera, diptera and hymenoptera
= lead tiers, rollers and miners feed internally between the upper and lower leaf epidermis
= wood and steam borers feed on bark, cambium, sapwood or heartwood of branches and trunks
= fruit and seed boers

= mandibulate herbivores also cause gall formations bu oviposition and feeding

18
Q

outline the category of herbivorous insects which are free-living sap feeders

A

insects which insert stylets into various plant tissues
= phloem feeders e.g. aphids
= xylem feeders = cicadas, frog hoppers
= epidermis/mesophyll/parenchyma feeder = thrips, heteroptera

19
Q

outline herbivory in the aquatic system

A
  • Aquatic systems use functional groups
  • Mandibulate herbivores
  • Sap feeders, e.g. lesser water boatman
    (Corixidae)
  • Shredders feed on living or decomposing
    plant tissues – some stoneflies
  • Collectors feed on plant fragments and small
    bits of organic matter
  • Divided into gatherers (mayfly larvae) and
    filter feeders (Blackfly larvae – Simuliidae)
20
Q

how can insects use additional indirect injury during herbivory

A

salivary or other toxins may be injected that can cause infection e.g. european wood wasp injects venom into conifer hosts causing lethal fungal infections

= sap sucking and root/shoot feeders may increase transmission of viruses, bacteria and fungi

= HAS A BIG ECONOMIC SIGNIFICANCE

21
Q

what are some ways plants defend themselves from herbivory

A

1) plant nuttrition = N and P limited
2) mechanical and structural barrier = toughness and hardness, trichomes and surface waxes
3) allelochemical barriers = secondary metabolites

22
Q

outline how plant nutrition can be used to defend against herbivory

A
23
Q

outline how mechanical and structural defences can be used to defend against herbivory

A

Toughness and hardness
– Hardness = initial cracking/splitting of tissue
– Toughness = resistance to crack growth
* Cellulose microfibrils in hemicellulose / lignin
matrix
* Amorphous silica in leaves, spines or trichomes
* Deter from feeding but also cause abrasion and
mandibular wear
* Sap feeders likely less affected by tissue
toughness
Trichomes have a diversity of forms, sizes and
densities – non-glandular and glandular
* Also insulate leaves, reduce evaporation and
aid water and nutrient absorption
* Reduce oviposition, alter movement -> reduce
growth and fecundity
* Hooked trichomes cause injury to Lepidoptera
larvae leading to loss of haemolymph,
desiccation and deat
Surface waxes protect against
desiccation and pathogen invasion
* Slippery surface prevents attachment in
some Lepidoptera larvae and aphids
* Some herbivores can maintain
attachment, e.g. Phyllotreta cruciferae
* Interactions between surface wax
structure and tarsal morphology
prevents certain species attachin

24
Q

how have insects evloved to counter mechanical plant defences

A

Relative head size of chewers of grasses (silica)
e.g. grasshoppers, caterpillars
* Extra moults to replace worn mandibles and chiseledged incisors
* Specialised tarsal claws or long proboscis for
trichome-bearing leaves
* Tarsal modification for waxy leaf surface e.g.
chrysomelid beetles
* Empoasca leafhoppers produce suction cup with
tarsal pads

25
Q

outline how allelochemical barriers can be used to defend against herbivory

A

Insecticidal properties of plants long known,
e.g. rotonene (Fabaceae) - 1848, tobacco -
1690, pyrethrum (Asteraceae) - 1880
* Action of secondary metabolites more
recently discovered (1940s – 1970) – play
little/no role in plant growth and
reproduction
* Thousands isolated from plants – clear
defensive role, but also other functions e.g.
protection from UV, storage and signalling

Allelochemical diversity → difficult to
categorise
* Qualitative / quantitative or toxins /
digestibility reducers
* Qualitative / toxins interfere with
metabolism, e.g:
* Alkaloids – Deadly nightshade (atropine),
tobacco (nicotine)
* Pyrethrins - chrysanthemum
* Cyanogenic compounds – Prunus sp

26
Q

what is meant by volatile organic compounds

A

secondary metabolites which are emitted by plants as a consequence of interaction with biotic and abiotic factors
= very important role in plant evolution
= floral VOCs ofetn invloved in defence or pollination attraction
= act as repellents or for indirect defences such as attracting parasitoids or predators

27
Q

how have insects evloved to overcome allelochemical barriers

A
  • Detoxification – most frequent mechanism
    uses enzymes to degrade allelochemicals
  • High pH, surfactants or redox potential can
    reduce effect of tannins
  • Development of alternate proteinases not
    affected by inhibitors
  • Excretion – Malpighian tubules remove
    nitrogenous waste including toxic alkaloids
    Sequestration of plant toxins as non-toxic form
    in haemolymph or toxins, e.g., cardelonides in
    monarch butterfly and milkweed bugs
  • Stored in cuticle, specialised glands or organs
  • Selective force may be defence as insects =
    aposematic
  • Specific transporters allow insect to control
    where and when toxins accumulate
  • Certain herbivores possess specific enzymes to
    boost bioactivity of the sequestered toxin
    Behavioural
    deactivation and
    avoidance – mass
    attack, vein cutting
  • Host-plant location –
    allelochemicals used
    as oviposition or
    feeding stimulants,
    used to identify
    weaker plant
28
Q

what are the effects of herbivory on ecosystem services on nutrient cycling

A

direct and indirect effects on nutrient cycling via
1) changes in carbon storage = induction of leaf fall, production of honey dew, defoliation

2) plant-plant comp - influence competitive interactions and affect plant composition

3) plant resource allocation - allocation to root, shoot, seed or flowers changes after attack

4) alteration of food webs - impacts microbial and mycorrhizal interactions

29
Q

what are the effects of herbivory on ecosystem services on decomposition and soil formation

A
  1. Available resources
    ‒ Quantity and quality of dead/decaying plants
    entering soils depends on plant species present
    ‒ Above-ground consumers can affect decomposer
    communities and plant nutrients available
  2. Effects on leaf litter quality
    ‒ Herbivory increases chemical defences which may
    persist in litter and affect rates of decomposition
30
Q

what are the effects of herbivory on ecosystem services on carbon and nitrogen cycling

A

o Termites and ants
1. Increasing surface area for microbial attack
2. Methane and carbon dioxide
‒ Termites can recycle carbon (as CO2 and methane)
to atmosphere via gut microbes
3. Nitrogen and Phosphorus
‒ Insects play a key role in cycling nitrogen via
consumption
‒ Most plant communities occur where there are low
levels available nutrient

Entomology (16 decks)

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