Introduction and Taxonomy

Question 1

secrets to success?

Answer 1

1. small size
2. fast reproduction

Question 2

1. small size
   - benefits?
   - size? mm

Answer 2

use many microhabitats, reduce resources required and effect of gravity

most species between 2 and 20 mm

minimal resources required for survival and reproduction

predator avoidance

low body size:body mass means higher proportional muscle mass

size limited by rate of oxygen diffusion

Question 3

2. Fast reproduction
   - benefits?

Answer 3

high rate of evolution - adapt to new conditions

high fecundity - females produce a large number of eggs - e.g. highest fecundity = Australian ghost moth

African Driver Ant - 3-4 million eggs every 25 days

high fertility - most of the eggs hatch

fast life cycle - often 2-3 weeks

allows adaptation to changing environmental conditions

Question 4

insects importance for ecosystem services

Answer 4

• plant propagation, pollination
• nutrient recycling, decomposition (decomposers)
• maintenance of plant community structure (grazers)
• maintenance of animal community structure (predators, parasites, vectors)
• estimated in US to be at least $57 billion

Question 5

Insect importance for keystone species

Answer 5

loss of ecosystem functions would cause collapse of wider ecosystem

keystone species are those that:
1. control potential dominants (parasitoid wasps)
2. resources providers (symbiotic bacteria in termites break down cellulose; pollinator species)
3. mutualists (plant-pollinator co-evolution - fig wasp; Lycaenidae butterfly family and ants)
4. ecosystem engineers (termites and ants, caterpillars)

if lose keystone species then ecosystem may collapse

Question 6

economic importance of insects

Answer 6

• economic value of pollinators and dung beetles
• cause £ billions damage to crops, stored food and animals
• roughly 20% crops grown fro humans to eat are eaten by insects
• control spread of disease
• 1 in 6 people currently infected by insect-borne disease
• malaria transmitted by some mosquito species kills one person /12 seconds
• vectors of disease for animals and plants
• can be problems but also v beneficial