Why are lepidoptera important?
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)
What methods are used to sample lepidoptera?
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
What has led to the decline in Butterflies?
Grassland butterflies have declined 50% from 1990-2011
- agricultural intensification
- poor/absent grassland management
- milkweed plant disappearing due to use of pesticides
- overwintering habitat disappearing due to deforestation in Mexico
Summarise moth populations
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
What are the key differences in butterflies and moths?
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