Motorway Shut to Let Butterflies Swarm Past

In the history of road transport, there can rarely have been such a poetic excuse for a traffic jam: Taiwan will close a busy motorway section this week to allow butterflies to flutter by.

Drivers on the Linnei section of Freeway No. 3 have been warned to expect delays as up to 1m purple-spotted butterflies per day flit along the road during their annual migration.

The closure of a 600-metre section of the elevated expressway reflects a growing ecological consciousness in Taiwan, which is famous for the diversity of its lepidopteran species.

The insects - also known as Euploeini or milkweed butterflies - fly north each spring to breed. During their brief migratory peak, more than 11,000 pass the road every minute, creating a blizzard of wings.

No car accidents have been reported, but conservationists say countless thousands of insects are splattered on windscreens, crushed under wheels or sucked into a vehicle's slipstream.

As well as temporarily closing a lane for the first time, the local authorities have also erected a net along the motorway aimed at forcing the butterflies to fly higher above the traffic. Local media said ultraviolet lights would also be placed under the road to guide the light-sensitive insects to fly safely underneath.

The measures, which will cost about £20,000 to put in place, were suggested by Lin Tie-shyong, associate professor at I-shou University's department of civil and ecological engineering. Prof Lin told local reporters he was surprised that officials had followed his recommendations.

The National Freeway Bureau said the plan was worth doing even if it led to traffic jams.

Taiwan is home to about 400 species of butterfly, 40 of which are unique to the island.