Entomology - Exam 3 Concepts

Why would one make an insect collection?

Fun?

Forced to for class

Work

Taxonomy and systematic studies

Agricultural pests

Biodiversity record (repeated surveys)

What are some active collection methods?

Hand picking

Turning rocks

Under bark

Lights

Nets (aerial, sweeping, aquatic)

Beating sheet

Aspirator

What are some passive collection methods?

Berlese funnel

Light traps (terrestrial and aquatic)

Sugar traps

Dung traps (Gainesville gold)

Carrion traps

Lindgren funnel

Attractants (pheromones)

What are lindgren funnels often paired with?

Pheromones

What are the different killing methods for insects for insect collections?

Injections (moths/butterflies)

Freezing

Ethanol (90-100% for DNA analysis)

Ethyl Acetate, cyanide (KCN)

What type of insects are lindgren funnels typically used to collect?

Wood-boring beetles

What is the label template for insect collections?

State: County

Location. Habitat

Date. Collector

Coordinates

What must a collection have to be properly maintained?

Pinned, ethanol via, or slide mounted (you can have all 3 for a single specimen)

Accurate label data

Database of collection data (may include images)

Maps

What percentage of insects are considered pests?

<1%

What are insects usually our most important competitor for?

Food

Wood

Fiber (Ex: Cotton)

Other Natural resources

What kind of impact do insects have on agriculture?

A direct negative impact

About how much do insects consume/destroy in populations?

Developed: 10% of gross national product

Underdeveloped: 25% gross national product

What are some insect related medical costs in the US?

Lyme disease: Around $1 billion

Mosquito-borne illnesses: Hundreds of millions of dollars

What is the global financial perspective of insect-related diseases?

$94.7 billion

What is used to help understand pest population dynamics?

GEP (General equilibrium position)

ET (Economic threshold)
EIL (Economic injury threshold)

When is treatment for pests required?

When the population density reaches its ET

What are the different categories for insects regarding pests?

Non-Pest

Occasional Pest

Perennial Pest

Severe Pest

What is the EIL affected by?

Weather

Pest’s predator populations

Neighboring Agricultural Activities

What is the equation for the EIL?

C/VDK

How is EIL used and developed?

It needs to be used and developed for each pest and crop under study

How do insects become pests?

When economic damage occurs at loss costs that exceed control costs

What are some factors that can lead to pests?

Monoculture of crops

Insect introductions where there are no natural enemies

Plant introductions to area where they have no defenses to the native insect fauna

What is the history of insecticides?

1858: First recorded use of pyrethrum in US

1867: Paris Green (copper (II) acetoarsenite) widely sold as insecticide and rodenticide 
1884: “Pyrethrum Soap” patented

1890: Mercury dust used as seed treatment

1948: Paul Muller won the Nobel prize in medicine for his discovery of insecticidal activity, which saved many soldiers’ lives during WWII

1972: The EPA canceled the use of DDT due to its adverse effects on the environment and human health

What are the unintended consequences of insecticides?

Genetic resistance

Death of beneficial insects

Pest resurgence

Secondary pest outbreaks

Environmental poisoning, biomagnification

Human health issues

What are the 2 types of resistance?

Cross

Multiple

What does insecticide resistance mean?

Ineffective chemical treatment

What are the different mechanisms of insect resistance?

Behavioral avoidance of treated crops

Physiological changes (sequestration, rapid elimination)

Metabolic resistance (detoxified by organism)

Target-site resistance (sensitivity decreases over time)

What is an example of biomagnification?

DDT

What are the goals of integrated pest management (IPM)?

Limit economic losses

Minimize killing of non-target species

Limit environmental degredation

What does the implementation of good IPM strategies require?

Research on the biology of the pest, the crop, and how environment conditions affect the pest and crop

What are the 4 control measures in an IPM strategy?

Chemical control

Biological control

Cultural control

Plant resistance improvement

What are some chemical control measures?

Attacking the most vulnerable stage

Contact, inhalation, and oral poisons

Insect growth regulators (juvenile hormone analogues)

What are some biological control measures?

Classical biological control

Neoclassical biological control

Conservation biological control

What are some biological control methods?

Nematodes (reared and spread on fields/forests)

Fungi (many fungi attack insects)

Viruses (expensive; some viruses only introduced to hosts via parasitic wasps)

Bacteria (Bacillus thuringiensis (Bt))

How does Bt work?

Ingestion

Activation in the gut (the alkiline environment of the gut breaks down the ingested crystal proteins into their toxic form)

Cell rupture (damages the midgut cells)

Stopping feeding and death (damage to the midgut paralyzes the insect’s digestive system)

Safety for other organisms

How is Bt safe for other organisms?

Highly selective

Toxic to insects that have the specific receptors in their gut that match the crystal protein

Protein breaks down quickly in the environment

What are some cultural control practices?

Crop rotation

Adjusting planting dates

Sanitizing soil

Choosing resistant varieties

Intercropping

Removing crop debris

Tilling

Using preplant herbicides

What are the functional traits of plant resistance?

Antibiosis

Antixenosis

Tolerance

How is resistance enhanced in plants?

Selective breeding

Genetic engineering

What are the main vectors of disease?

Adult Diptera

What are the casual agents of insect spread diseases?

Protists

Viruses

Bacteria

Nematodes

Parasites (cause damage without causing disease)

What are some examples of secondary cycle diseases?

Plague

Yellow Fever

What spreads malaria?

Anopheles sp. mosquitoes (only 30 species transmit malaria to humans)

What is the disease causing organism of malaria?

Plasmodium falciparum and 4-5 other Plasmodium species (eukaryotes in the phylum Apicomplexa)

What are the life cycle stages of plasmodium in humans?

Asexual reproduction

1. Mosquitoes transfer them via saliva

2. Sporozites travel via blood to liver, form schizont

3. Merozites release from liver to reinfect liver and WBCs

4. Trophozoites feed in WBCs

5. Trophozoites mature into M/F gametocytes, uptaken by mosquito when feeding

How do mosquitoes asexually reproduce?

Sporozites form in oocyte, transferred during feeding

What is the history of malaria in the US?

Common through the late 1800s

During the early to mid-1900s, the area where malaria cases occurred within the US shrank to southern states

By the 1950s, the US was declared malaria-free through improved sanitation and widespread mosquito control efforts

How are most of the cases of malaria in the US occurred?

Mostly travel-related

What are the factors important to spread malaria?

Vector distribution

Vector abundance

Vector survival rate (longer life increases transmission success)

Anthropophily of vector (how much do they want to feed on people)

Feeding interval (determines transmission rates)

Vector competence (correct host)

What is the vector of malaria?

Mosquitoes

What are the pre/post infection drugs that are used to control malaria?

Atovaquone/Proguanil (Malarone)

Doxycycline

Mefloquine (Lariam)

Chloroquine (Avloclor)

What are some ways to control mosquito populations?

Insecticides

Removal of larval habitats near habitations

Bed nets + Insecticides

Multiple insecticides to thwart insecticide resistance

What are some examples of arboviruses?

Yellow Fever (mosquitoes)

Dengue Fever (mosquitoes)

Encephalitis (mosquitoes) (no vaccine for mosquito-born, only tick-borne)

West Nile Virus (mosquitoes)

Zika (mosquitoes)

What is typhus?

Spread by body lice (blood feeders) infected with Rickettsia bacteria

Enters the body when lice feces are scratched or rubbed into the bite wound

What is the plague?

Spread by rodent-fleas caused by the bacterium Yersina pestis

What are some non-malarial protists?

Trypanosoma (kissing bugs and tsetse flies) (causes chaga’s disease and african sleeping sickness)

Leshmania (sand flies) (causes internal and external lesions)

What are the two main diseases that nematodes cause in humans?

Bancroftians filariases (elephantiasis)

Brugian filariases (river blindness)

What are the 3 main genera of mosquitos to be aware of?

Anopheles

Aedes

Culex