Butterflies and Moths

Question 1

Why are lepidoptera important?

Answer 1

Key component of many food webs - both adults and caterpillars (bats, birds etc)
As indicators to environmental health - short life cycles and thus react quickly to environmental change
- limited dispersal, specialised food plant and close reliance on the weather make many sensitive to fine scale changes
- declining more rapidly than birds
- Occur in all main terrestrial environments in the UK except dead wood and so can potentially be an indicator species for a wide range of habitats
- Well documented taxonomy, easily identifiable
Value in plant pollination
Approx 2500 species in Britain (150,000 global)
Cultural significance

Question 2

What methods are used to sample lepidoptera?

Answer 2

UK butterfly monitoring scheme - Transect on a weekly basis April to September
- 2-4km long, taking ~45 mins
- Transect fixed width band (5m wide)
- suitable weather, dry, not windy, warm
Moths
- sugaring, painting a sugar mixture onto tree trunks
- wine ropes
- light traps

Question 3

What has led to the decline in Butterflies?

Answer 3

Grassland butterflies have declined 50% from 1990-2011
- agricultural intensification
- poor/absent grassland management
Monarch butterflies
- milkweed plant disappearing due to use of pesticides
- overwintering habitat disappearing due to deforestation in Mexico

Question 4

Summarise moth populations

Answer 4

Twice as many moth species have declined as have increased
The number of larger moths in Britain has decreased by 32%
Southern Britain has seen a decrease in larger moth numbers of 44%
In urban areas the loss has been 50%
In Southern Britain 75% species are in decline
62 moth species became extinct during the twentieth century

Question 5

What are the key differences in butterflies and moths?

Answer 5

Antennas - moths have feathery antennae while butterflies have clubbed antennae
Resting posture - moths have arched wings while butterflies have upright wings
Lifestyle - moths mostly nocturnal butterflies mostly diurnal
Reproduction - Moths pupae often spin a cocoon, butterfly pupae form silken shelter, often with plant leaves