GCPM

Monocultures are good for specialized species —> higher densities in simple environments;

Herbivores, specialized on a certain crop species, are more likely to find and remain on their host plants in larger monocultures resulting in higher pest densities.

Example : pollen beetle

Natural enemies are more abundant in more diverse crops resulting in higher predator pressure and lower pest densities.

Usually small scale farms have a higher crop diversity.

Example pollen beetle

Species richness can buffer against fluctuations in ecosystem functioning;

seemingly redundant species can become important in the maintenance of biological control following disturbance

Accessibility of host trees: resource concentration, ability to locate hosts

Impact on natural enemies: alternate hosts, food for adults, shelter; but also reduced foraging efficiency in complex situations

Pest shift among host species

-> resource concentration hypothesis

Larger animals in colder environments

Low surface area to volume ratio

Less body heat loss per unit of mass

Stay warmer in cold climates

Dark coloration increases solar radiation absorption

Speed up heat gain

The higher the trophic level the lower the biomass

Natural enemies: more mobile and larger than prey/host

Pest species well adapted to climatic stress, natural enemies not

Potential decoupling of prey-natural enemy interactions

Brassica

-> CO2 increase -> higher glucosinolate level (secondary metabolite)

B. brassicae aphids

Lower body size of aphids (host - pest interaction)

D. rapae

Pest - parasitoid interaction

Parasitism is size-dependent: small aphids are not suitable as host -> decreased because of reduced host body size

M. Trunculata

Higher biomass (elevated CO2)

Pea aphid

Host plant and pest species dependent on genotype

Parasitoid Aphidius avenae

Pest and parasitoid

Depending on genotype

Lower parasitism at eCO2 induced by size shifts

no significant effects alone on predation

Direct host-prey interaction

B. Nigra (B. napus) CO2 increased chemical plant defense

—>M. persicae higher predation (generalist feeder)

-predation rates not effected by CO2

—>B. brassicae reduced predation (specialist feeder) —> sinigrin content

Direct prey-predator interaction

Predator E. ealeatus

-predation rates of B. brasssicae decreases with increasing CO2

Indirect effects on insects:

increases survival and fecundity

pest outbreaks are more likely in well fertilized cultures

faster juvenile development, lower juvenile predation risk

Stressor is the predator (bird)

the coulour shifts from green to brown

the beetles are no longer easy to distinct —> no/less food

chemical pesticides: lead to resistances —> only the pests which aren´t sensitive to the chemical will survive

consequences: different management methods are needed; more multi-side pesticides

field species is resistant ageinst Bt

the Bt producing maize in b has a different Bt strain —> field species is not resistant against that one

the field population might have a cross resistance because it is a bit more resistant against the second strain but not enough

D. suzukii: broad food range,

abiotic resistance: adaptive phenotypic plasticity increases winter survival,

biotic resistant against native parasitoids because of activated immune response

selective advantage against native food competitiors (saw-like ovipositor)

H. axyridis: broad food range,

abiotic resistance: dark winter morphs increase survival (winter suvival),

biotic resistance: strong immune response against pathogens and parasitoids strong IG predator (intraguild predation IPG)

Causes for faild invasions:

Propagule pressure

Abiotic resistance of native ecosystems

Biotic resistance of native species communities

Propagule size: released individuals per introduction

Propagule number: number of introductions

Phenotypic plasticity: ability of an organism (genotype) to shift its phenotype in response to environmental cues.

D. suzukii: temperatue and photoperiod

high

-> augmentative = more introductions = frequent releases

-> biocontrol agent -> high numbers of agents

D

bigger in winter, longer wing length, (more dark morphs) darker in winter

females > males (Winter>summer)

B):

Heat balance hypothesis

->Low surface area to volume ratio

->Less body heat loss per unit of mass

Thermal melanisation hypothesis (?)

Lower nutritional value for herbivores, not compensated by higher pest feeding rates

Higher plant biomass: dereased levels of primary metabolites

Increased mechanical defense

-> increased levels of secondary metabolites

Lower performance of herbivores

larval development nedds more time with higher CO2 conc.

pupal weight reduces with higher CO2 conc.

2) No

->Decreasing survival probabilities

->Mortality increases with progressing development

3)

Altered nutritional value of host plants (plant is not as nutritious; need of higher biomass intake)

Changes in plant defense mechanisms (plant produces more secondary metabolites)

A)

M. persicae generalist feeder —> excretion of sinigrin (detoxification)

B. brassicae specialist feeder —> accumulation of sinigrin in the body (immun agains it)

B) M. persicae because B. brassicae uses the sinigrin as a defences against predators

Life history:

growth, maturation, reproduction, survival

Juvenile development:

juvenile survival, age at maturity (developmental time), growth, size at maturity (body size)

Adult phase:

reproduction: egg number and size; survival

Temperature change:

Increase of Tmean

More mild winters —>permanent establishment

More hot summers/heat waves —> increases the capacity for population increase (high fecundity)

high propagule pressure

Abiotic resistance of native ecosystems: the thermal sensitivity of an alien biocontrol agent

Faster juvenile development at high temperatures: beneficial

Smaller body size at high temperatures: possibly a disadvantage

Seasonal establishment, no winter survival: very likely

occasional winter survival in years with very mild winters: open question

Permanent winter survival and establishment because of climate warming: openquestion

expansion of the pine processionary moth (Thaumetopoea Pityocampa)

less cold temperatures

higher temperatures help them to digest their food

winter larval feeding now possible in more regions

A)

CTmin 10°C

CTmax 30°C

Topt

Age at maturity: 20-30°C

Size at maturity: 10-15°C

B)

rapid development, small size and vice versa

aphid white bars has the highest abundance

aphid grey bars the lowest abundance

White bar aphid lower abundance at high EHTs frequency

grey bar aphid lower abundance at any EHTs frequency

black bar aphid higher abundance at high EHTs frequency

—> black is the most heat resistant species

WGP: plastic response to environmental stress within a generation (in the figure: plastic response of F1)

TGP: environmental stress experienced by parents affects offspring phenotype (in the figure: parental modification of F2)

More beneficial with heat waves —> faster adaption

increase of the mean temperature —> slower adaption (genotyp differences)

A)

females larger

males didn´t change in size

B)

The female response is adaptive because they change in their size depending on the outcome of the parents (parents had experients with heat wave conditions —> child bigger under hear wave condictions than th summer conditions child)

Long-range localization of spider mite infested plants by P. persimilis under heat stress

Does heat stress alter herbivore induced plant volatiles(HIPV‘s)? Yes

HIPV concentration at 30°C: higher than at other temperatures

HIPV production: negligible at 40°C

Does heat stress influence the localization performance of P. persimilis? Yes

Unability of P. persimilis to perceive HIPV‘s and localize spider mite infested plants at +35°C

Unability of infested plants to produce volatiles at +40°C

->host had higher increase of RMR rates under thermal stress

->S. avenae increased its defense behavior under thermal stress

->the oviposition success of A. rhopalosiphi was lower under thermal stress

->thermal stress can disrupt the interaction of S. avenae and A. rhopalosiphi

->Climate warming may result in lower control success of S. avenae by A. rhopalosiphi

Conclusions

38°C

Clear negative effects on predation success by predator-prey body size ratios, predator and prey were not affected by each other, predator, but not prey suffered from high temperatures by decreased VeloMax

Potential effects on biological control

Female prey might be superior over predator at 38°C

But the periods of daily high temperatures during heat waves are short (about 6h), predator may predate on prey when the daily temperatures are lower

a) higher metabolic rate -> higher capacity to react

b) the host has a higher RMR and has therefore the advantage

A) the mites chose the infested plants

at 35°C there is no significant difference in choosing

B) herbivor induced plant volatiles (HIPV´s)

C) either the plant can´t produce the volatiles under heat stress

or the mites can´t smell the volatiles

A) The predator exhibited no preference because of similar HIPV’s

B)Predator is perceiving the higher concentration, because of the preference of plant volatiles produced at +30°C

drought stress supports herbicor insects

->good development conditions

->plants suffering from drought stresss can have better nutritional quality

->severe drought stress reduces defense mechanisms

Prevention would be best

early detection -> early recognition

Lists of quarantine pests, priority pests etc.

protection against introduction. surveillance, control

Risk-based controls

->risk activity

import and storage of non-squared wood

import of goods with wood packaging material

—>storad or traded, nurseries, garden centre

->risk location

storage facilities of wood processing industries

locations where goods with WPM are

plants for planting

Supports both

Enemy hypothesis: Natural enemies are more abundant in more diverse crops resulting in higher predator pressure and lower pest densities.

Resource concentration hypothesis: Monocultures are good for specialized species —> higher densities in simple environments

high propaglue

adaptive phenotypic plasticity induced by climate

heat balance hypothesis

thermal melanization hypothesis

Natural enemies: more mobile and larger than prey/host

Pest species well adapted to climatic stress, natural enemies not

Example:

predator - prey relationship: P. persimilis - T. urticae (prey location)

host - parasitoid relationship: S. avanae - A. rhopalosiphi (host overwhelming)

precipitation

bark beetle is negativly affected by high precipation rates

host tree might be positivly affected

temperature

bark beetle is positivly affected by high temperatures

host tree might be negativly affected

topography is extremly important

daytime is depending on north/south —> no sun -> temperatures go down

Green genotype: larger at elevated CO2

Pink genotype: smaller at elevated CO2

Green genotype

Larger body size at elevated CO2

Higher plant biomass, nutritional value not affected by CO2, no induction of chemical plant defense

Pink genotype

Smaller body size at elevated CO2

Higher plant biomass, nutritional value not affected by CO2, but the induction of chemical plant defense resulted in smaller body size

a) permafrost core sampeling

b)

Change in water availability (precipitation amount or temporal distribution)

Temperature increase (thawing of permafrost, shift of tree line

Acidification of the ocean (coral bleaching, … )

Neobiota including pests and diseases

Natural dispersal

Transportation by human activities (e.g. Hitchhiking)

Lists of quarantine pests, priority pests etc.

protection against introduction

surveillance, control

Risk-based controls