Butterfly numbers wiped out by last summer’s hot dry weather could take close to a decade to recover, fear experts.

Last summer’s record temperatures, heatwave and subsequent drought caused some plants the caterpillars feed from to wither and die.

Without sufficient food many caterpillars are thought to have died along with them, which will now hit hard the number of butterflies in subsequent generations.

Charity Butterfly Conservation says after record-breaking heatwaves in both 1976 and 1995 butterfly numbers ‘crashed’ the following year and took almost 10 years to recover.

Launching this year’s Big Butterfly Count, scientists say it’s more important than ever that they understand the effect extreme weather is having on our butterfly populations.

Dr Zoë Randle, Senior Surveys Officer at Butterfly Conservation explained: “This is a vital year for the Big Butterfly Count. We know that the previous extreme summer droughts in 1976 and 1995 took a heavy toll on butterflies and numbers crashed the following year, taking almost a decade to recover.

“The data collected during this year’s Big Butterfly Count will give us a valuable insight into what the effect of the most recent extreme weather has been, and how we might be able to better protect our beautiful butterflies. With climate change here to stay, we need people to take part more than ever before.”

Butterfly Conservation’s Big Butterfly Count is the largest citizen-science project of its kind and requires people to spend just 15 minutes looking for and counting the numbers of butterflies near to where they live.

It is open to anyone of any age in any part of the UK, providing logs are carried out before the August 6 deadline, with surveys from back gardens to balconies welcomed.

The information is then used to inform conservation projects, government policy and to help support experts with vital research into the health of the planet.

With so many British butterfly species thought to be hovering on the brink of extinction, the data people can gather is vital says Dr Randle.

She added: “We know 80% of butterflies in the UK have declined since the 1970s. Which means there are fewer butterflies to be seen than in years gone by. However, even if you don’t see any butterflies during your Count, we still want you to tell us.

“We need to know where there aren’t any butterflies just as much as where there are, so please still log your result and then pick another day or location and try again. There are no limits on how many times you can take part.”