Wall brown butterfly 'may be a victim of climate change'

Evidence suggests butterfly is dying out because warmer weather is causing generations to hatch out too late in the year to survive, scientists say

Patrick Barkham

Wednesday 24 December 2014 12.13 GMT

The dramatic decline of one of Britain’s butterflies may be because climate change is creating a “lost generation” according to research by Belgian scientists.

The disappearance of the wall brown (Lasiommata megera) from swathes of southern England has mystified conservationists for two decades but new evidence suggests that the butterfly is dying out because warmer weather is causing generations to hatch out too late in the year to survive.

In recent years, instead of the offspring of the wall butterflies found flying in July and August spending winter as a caterpillar before emerging as a butterfly the following year, warm conditions encourage the caterpillars to quickly turn into a butterfly by September and October.

By emerging so late in the year, these butterflies fall into what researchers, led by Professor Hans Van Dyck of Louvain University, call a “developmental trap”. By autumn, it is too cold and there are not suitable plants for their offspring to eat before winter. In effect, these autumn butterflies are a lost generation, leaving no caterpillars that can survive to become butterflies the following spring.

Continued ...