Entomology Final

What insect order seems to be the most affected?

Hymenoptera

Which of these is not a factor discussed in class in a changing world?

New weather patterns

List and describe both mechanisms of mating disruption confusion

False-trail following (male moths would spend time and energy following pheromone trails to false sources), masking/camouflage. (fill air with pheromones to lose trail of any females)

What is a period of dormancy in DIRECT response to adverse environmental conditions?

Quiescence (a short period of dormancy directly induced by adverse conditions that can be quickly reversible when favorable conditions return)

What does water limitation do to plant physical defenses?

Decreases plant physical defenses, increases chemical defenses

What is a pest?

Organism that reduces the quality/quantity/value/availability of some human resource.

Name and describe two ways insects deal with adverse conditions.

Quiescence- period of delay development in direct response to adverse environmental conditions

Diapause- period of delayed development in response to recurring period of adverse environmental conditions

How has insect biomass changed since 2024 as a percent?

-78%

What were the factors that lead to DDT being banned

Pests evolving resistance to DDT.

Long term persistence of DDT in the ecosystem, and it rising up the food chain (notably the Bald Eagle shell weakening)

Human adverse health effects (endocrine disruptor)

Low efficacy (only reached 1% of the target pests)

Secondary pest outbreaks due to either natural predators or competitors being killed

Negative perception (silent spring)

What is the best way of applying pesticides for maximum effectiveness?

Use pesticides only when scouting or damage shows a need.

Dispersal is movement away from the birth site. (T/F)

True

What is the difference between pest resurgence and a secondary pest outbreak?

Pest resurgence occurs when pesticides kill the natural predator of a pest so when the pest becomes resistant they recover in larger numbers. A secondary pest outbreak occurs when an insect that wasn't previously a pest sees a population outbreak and takes over the niche of the previous pest.

What type of natural insecticide works by removing the protective waxy layer that prevents desiccation in insects?

Soaps

How do insects deal with adverse conditions in order to survive?

Dormancy, dispersal

Which of the following is NOT a natural insecticide?
A. soap

B. organophosphates

C. botanicals

D. mineral oil

B.

What is a sugar producing gland outside of the flower, most commonly on leaf petioles, stems, or in proximity to reproductive parts?

Extrafloral nectaries.

Quiescence

A period of delayed development, slowed down body processes (dormancy), instead of senescence (death); done in direct response to adverse environmental conditions

Diapause

A period of delayed development (dormancy) in response to predictable/recurring adverse environmental conditions/events

What are the 2 things that decrease during plant drought stress?

Plant growth rate and Physical defenses

Which plant family produces Cardenolides?

Apocynaceae

Name problems we have discussed in class that are currently impacting insects /List factors that are leading to a decline in insect populations.

Temperature, CO2, water availability, invasive species, habitat loss/degradation, agricultural intensification, urbanization/suburbanization, light/chemical pollution.

Define LD50. Include the units by which LD50 is measured.

Abbreviation of lethal dose - 50%; the dose (mg of active ingredient/kg body weight) that kills 50% of the test population to which it was administered.

Name a common insectary plant discussed in class.

Sweet alyssum, dill, buckwheat, fennel, sunflower, basil, mighty mustard.

What is IPM?

A pest management strategy that integrates the use of multiple suppressive tactics for optimizing control of insect pests in an economically and ecologically sound manner.

Who lead the push to implement IPM nationally

President Nixon & Carter

What is the keystone of IPM?

Bioeconomics

Injury is how the plant responds to damage (T/F)

False. Damage is how the plant responds to injury

The EIL is a fixed amount of tolerable losses until it becomes economically feasible to intervene

False [it is a dynamic threshold, and, worth noting: the ET is the trigger for intervention (before EIL is met).

Define parasitoid

Feeds on or in hosts in immature stages, free living adult.

The economic injury level is a number that represents the reduction in crop yield caused by direct or indirect insect damage. (T/F)

False

Describe why combining HIPV lures and habitat manipulation might provide better results than either alone.

Combining both techniques is helpful because the HIPVs attract natural enemies, while the manipulated habitat gives the enemies the space and resources to grow their population. This is especially important because HIPVs alone can only redistribute enemies within an ecosystem, and habitat manipulation can help make up for this limitation.

What are the three main approaches to biological control?Briefly describe each.

Classical (importation): Introducing natural enemies from a pest's native range to control it in a new area.

Augmentation: Releasing mass-reared natural enemies to boost their populations.

Conservation: Modifying the environment to protect and encourage existing natural enemies.

Herbivore-induced plant volatiles (HIPVs) function as direct plant defenses by repelling insect herbivores.

False. HIPVs are indirect defenses that recruit natural enemies to the herbivores rather than repelling the herbivores themselves.

What is a chemical called if it is not discriminative against certain insects?

Broad spectrum

What is the purpose of an extrafloral nectary

A gland on a plant which produces sugar to increase the fitness of pest predators and parasitoids

EIL (Economic Injury Level)

(Cost)/(Value x Damage)

Higher survivorship during diapause, less snow cover for thermal protection, and diapause timing mismatches in insects are all consequences of what?

Mild Winters

What occurs when the value of yield lost is greater than the cost of management?

Economic Damage

When does economic damage occur?

When value of yield lost is greater than management costs.

Define biological control of insect pests and give an example of a type of biological control.

The purposeful support or manipulation of natural enemies to obtain a reduction in a pest's status. Examples: importation, augmentation (buy & release), conservation - insectary plants, indirect plant defense (maintain defensive force or call for help).

Poikilothermic

The inability to maintain body temperature using homeostatic mechanisms, or the inability to maintain a body temp that differs from ambient conditions.

When did the era of pesticides begin?

1939

Ectothermy

The inability to physiologically regular the body temperature relative to the surrounding environment 

What will happen to insects as things heat up? 

Faster generation times possible, egg to adult faster which could mean more generations in a year, possible higher abundance overall 

Higher survival (escape from enemies) possible, some insects are better at evading their predators/natural enemies. Slower development means more prone to predation.

Eggs, nymphs are vulnerable so the more quickly the adult stage is reached, the better an insect is off 

Predicted changes in plants from increased CO2

(UP) Faster rate of growth due to increase in photosynthesis 

(UP) Reduction of % nitrogen in leaves (~15% decrease in foliar N) 
(DOWN)Nitrogen dilution effect > if everything is equal and plants are growing more, the nitrogen is diluted in those larger plants 

(UP)Increase in carbon based insect defenses (tannins for example) 

General insect responses to elevated CO2  

Insects are eating more (compensatory feeding) 

More vulnerable to enemies, higher mortality rate 

Slow-growth, high mortality 

Higher rates of feeding even if not compensatory – concentration of other compounds such as sugar may affect this (sugars is a phagostimulant; eat more food!) 

Abundance of insects will decrease  

Fewer total insect and a trend towards lower survivorship 

Development time increases, slows down and performance declines 

Pupal weight goes down 

Conversion efficiency

How much energy in food translates to energy in insect.

Relative consumption rate

How much relative to body weight is eaten

Relative growth rate

How much mass consumed is translated to mass added in growth.

General responses to drought

Less water, decreased biomass due to less photosynthesis + restriction of photosynthesis 

Free amino acids increase (nitrogen) 

Plant chemical defenses will increase

Plant physical defenses decrease (resin, specifically)

Oranochlorines (ddt ect.)

DANGER

Broad spectrum, higholy toxic to insects

Mode of action = axonic poison

Concerns: environmental persistence

Fat soluble (biomagnification) -> concentrates in organisms higher up in the food web, doesn't get flushed out of system but instead resides in fat cells

Chronic effects to vertebrates

Organophosphates

WARNING

Broad spectrum 

Less persistent than organochlorines 

Less biomagnification 

Mode of action: synaptic poison 

Concerns: generally more toxic to mammals than organochlorines 

Carbamates

CAUTION 

Broad spectrum 

Persistence similar to organophosphate 

Mode of action: synaptic poison 

Concerns: toxicity to pollinators and parasitoids 

Allelochemical

A compound used by the plant to defend itself against herbivores 

Pyrethrum (Pyrethrin) 

Most widely used botanical 

Broad spectrum 

Low mammalian toxicity 

Low persistence (good and bad) 
mode of action: axonic poison 

Drawback: requires synergist to prevent detoxification by insect 

Pyrethroids

Synthetic analog of pyrethrum, more stable in UV 

High insect toxicity, low mammalian toxicity, broad spectrum, mode of action = axonic poison 

Concerns: toxic for fish and some non-target invertebrates 

How to avoid resistance to insecticides? 

1. Avoid prolonged exposure to a single insecticide 

2. Raise economic threshold recommendations 

3. Use insecticides with different modes of action