General Entomology

Question 1

Why are insects successful?

Answer 1

• exoskeleton
• ability to fly
• short generation time
• small size
• reprodutive capacity

Question 2

What is an exoskeleton?

Answer 2

Outer ‘shell’ of insect.

Provides structure, support, protection:

• keeps insect from drying out
• base for attachment of muscles

Question 3

What are the parts of the exoskeleton and what are they made of?

Answer 3

1. Epicuticle
2. Exocuticle
3. Endocuticle
4. Epidermis

Epicuticle: outer layer, non-cellular, secreted by epidermis… shed or reabsorbed during molt. Made from chitin (complex polysaccharide), protein (sclerotin), quinones, lipids, and wax

Epidermis: cellular, inner layer

Question 4

How can arthropods perceive their environment from inside a hard shell?

Answer 4

External sensory structures, sensory hairs

Question 5

How can insects benefit from being cold blooded? Give an example.

Answer 5

Thermoregulation - shortens generation time.

Ant mounds are solar collectors… immatures are up top to speed up development.

Question 6

What are positive influences of insects on humanity?

Answer 6

• products - silk, honey, wax, shellac
• services - pollination, decomposition, biocontrol
• food - termites, catepillars, honeybees
• research tools - fruit flies

Question 7

What are negative influences of insects on humanity?

Answer 7

• vectors - plant / animal disease
• contamination of food
• direct crop loss - feeding on products
• indirect crop loss - defoliation of plants
• impant of human possessions

Question 8

What percent of insects are pests?

Answer 8

Less than 1%!

Question 9

What are the seven ways that an insect can become classified as a pest?

Answer 9

1. Entry into new regions - Japanese beetle (no natural enemies)
2. Shifts in host-plant preference - apple maggot fly (hawthorn -> apples)
3. Changes in biology / genetics of host - dogwood (understory, full sun -> borer damage)
4. Change in cultivation - monocultures (CO potato beetle)
5. Changes in management / technology - insectide resistance, no till -> more OW
6. Changes in consumer preference
7. Changes in disease competence - Asian citrus psyllid (citrus greening)

Question 10

Is the classification of ‘pest’ primarily economic or ecological in nature?

Answer 10

Economic, based on:

• market value
• crop susceptibility
• environmental factors