Leylandii: What is it Good For?

Well, it turns out that my neighbour’s not very attractive (IMO) non-native Thuja hedge is good for these two non-native Mediterranean moths! Blair's Shoulder-knot (Lithophane leautieri, #763) was first observed in UK in 1951 and is now established over most of lowland UK. It flies in one generation Sept-Nov; this being the first one I’ve recorded. Cypress Carpet (Thera cupressata) arrived in 1984 and so far its main range in UK only extends as far North as Birmingham. If has two generations, one in May-June and another in August-September.

#970 Blair's Shoulder-knot (Lithophane leautieri)

#763 Cypress Carpet (Thera cupressata)

Not a Bee - Narcissus Bulb Fly

It looks like a bumble bee, but the face and antennae are not quite right; in fact it is a type of hoverfly. The Narcissus Bulb Fly (Merodon equestris, #495) is another non-native garden pest, this time a long-term one, imported (no doubt with foreign bulbs) around 200 years ago, it lays its eggs on the dying leaves of daffodils and other bulbs, where its larvae burrow down to feed on the inside of the bulb. This one was in and among my daffs. Usually there is only one larva per bulb, but as it lives in the bulb for a year it has plenty of time to eat the heart of the bulb, including the developing flower bud. The emerging adults only live for a week or two, during May/June. Its bee-like appearance is thought to be a deterrent to would-be predators.

#495 Narcissus Bulb Fly (Merodon equestris)

Small Snails

Lots of snails made it through the winter and have come crawling out of garden waste in the composting bin. Strawberry Snail (Trochulus striolatus) on the left, is one of the commonest snails in the garden, but the Girdled Snail (Hygromia cinctella) on the right is a new one for the list (#428). Girdled Snail has a distinctive white stripe around its keel and the shell is smoother than on the similarly-sized Strawberry Snail. It is yet another non-native species, originating in Mediterranean Europe and only discovered in UK in 1950 in Devon. From there it has slowly spread over much of the England, as it has also crawled its way across much of Central and Northern Europe.

#243 Strawberry Snail (Trochulus striolatus)

#428 Girdled Snail (Hygromia cinctella)

Australian Immigrant

My first new moth for a while, a Light Brown Apple Moth (#317), is originally a native of Australia.  First found in UK in the 1930s it's now spread across much of England making a pest of itself in orchards and gardens.  Similarly, it's been accidentally introduced to New Zealand, New Caledonia, Hawaii and California.  In Australia the population is kept under control naturally by insect predators, especially parasitic wasps and flies, that eat the larvae.  However in other countries these predators are not present, so the moths can become a significant pest in orchards.  It's an interesting reversal of all the non-native plants and animals introduced (often deliberately) to Australia and New Zealand by European colonists, which now have to be controlled at great cost by local farmers and conservationists.  

#317 Light Brown Apple Moth