Its good to see that hoverflies (pictured) are faring well this summer compared with last year when very few were around. A healthy population is good news for gardeners as along with the larvae of ladybirds and lacewing flies, hoverfly larvae eat large numbers of harmful aphids and greenfly.

In the insect world, any that show black and yellow or black and red colouration are instinctively left well alone by would be predators as they could be toxic or unpalatable and as miniature wasp lookalikes, hoverflies, although harmless, gain protection from their mimicry.

Hoverflies are strong migrants and frequently swell our native population by flying across the channel in hot weather.

Several years ago I was staying in a clifftop hotel on the south coast and throughout my ten day stay billions of hoverflies flew in from the sea, up over the cliff, across the road then onwards over the hotel, although many became trapped in open windows. The migration continued all day, every day and into dusk.

A few weeks ago in this column I expressed concern about white butterflies and their comparative scarcity in June, but hoped more would appear as summer progressed.

So, I'm pleased  to see that is indeed the case and many are flying in the hot weather. White butterflies are also strong migrants and our native population may well be augmented by many flying in from the Continent..