Bugged by the hugely under-recorded presence of earwigs

ANOTHER LIFE:THE SCIENTIFIC urge to know what's left of the planet's other species and where they all live has had to reckon with the ultimate and dazzling diversity of insects.

Darwin commented that God seemed to have an inordinate fondness for beetles, but the range of other creatures that walk the earth on six legs needs endless and painstaking sorting and tracking, even on these modestly accommodating islands. My drawing, for example, shows some of the 180 or so hoverflies in Ireland, many of which mimic bees and wasps.

A couple of large documents thumping into my letterbox have completed the basic checklist of all the insects in Ireland. One, with a giant bed bug on its cover, deals with 1,684 species, from mayflies to earwigs and dragonflies to cockroaches – “The Irish Hemiptera and Small Orders”, as the title puts it, remaining to be rostered. The other lists Irish insect research over the past 10 years – a document needing as many pages as covered the previous 20.

Both volumes come from the Irish Biogeographical Society, of which Dr Jim O’Connor, now retired as the Natural History Museum’s chief and indefatigable “bug man”, has been editor and mainstay since 1975.

Biogeography studies the distribution of plants and wildlife and reflects the fieldwork of hundreds of Irish botanists, biologists and entomologists.

But a new appeal from the National Biodiversity Data Centre, based in Waterford, shows how mapping the whereabouts of even common insects can need the help of anybody with a garden or other leafage in their lives.

The Irish centre’s counterpart in Britain, the Biological Records Centre (BRC) based at Wallingford in Oxfordshire, is developing an atlas of grasshoppers, crickets, earwigs and stick insects for the UK and Ireland.

What exactly groups these different families of insects together is, frankly, puzzling, but the need for a geographical fix of records has thrown up a gap in one, in particular – where are the earwigs? Well, everywhere, you might suppose. But supposition isn’t science, and their presence in Ireland is hugely under-recorded, especially in the west.

What’s needed is eye-witness accounts: an earwig crawling out of the cauliflower, curled in the stalk-cup of an apple on the tree, or descending from a vase of dahlias (all necessarily home-grown, not supermarket-bought). These are typical resting-places for the insect, which likes to press its skin against something smooth, but any encounter is notable.

In sending a record to iti.ms/Pyzp6n, you are free to assume that the insect is the common earwig, Forficula auricularia, and not one of another two, smaller, Irish species, which are rare and hard to find. Crickets, grasshoppers and stick insects are another matter and may well need the help offered at iti.ms/NAtIZt.

There are, for example, five native species of bush-crickets and cone-heads and another five of grasshoppers, together with assorted non-native camel crickets and true crickets. Where this leaves Acheta domesticus, the cricket that once chirped at many an Irish turf-fired hearth, is unclear.

The insect is now thought at least rare and possibly extinct, though one chirped at intervals in our house until about 1990 – the year that one also jumped out of a fireplace in a fairly new, centrally-heated house in Castleknock in Dublin. In Britain, A. domesticus is said to still thrive in the warmth of fermenting rubbish dumps, of which Ireland surely has a few.

As for stick insects – yes, Ireland has had them for a century, notably in the mild, moist, near-sub-tropical climate of the Kerry and west Cork coasts. The southwest of England has them, too, and the original source is the same: Treseder’s nursery in Truro, Cornwall, early specialists in bringing Australasian plants to Europe. Among Treseder’s Irish customers was Viscount Mersey, with estates around Kenmare Bay in Co Kerry, where several colonies of stick insects now flourish.

They are the “unarmed” stick insect, Acanthoxyla inermis, so called because they lack the spiny defences of the prickly stick insect that also occurs in Cornwall (as does the smooth stick insect, long thought to be the species in Ireland). And although the southwest’s balmy gardens are famed for tree ferns, in the roots of which its eggs arrived,

A. inermis is quite happy with brambles, rose-bushes, fuchsia or even wayside heather, which is where friends of mine saw one, near Rossdohan, in 1997.

A stick insect is a phasmid, a pleasant name, and even at the adult size of 12.5cm – the biggest leaf-eating insect in Ireland, by a long way – it can be invisible right in front of your eyes.

Being parthogenetic, which means it doesn’t need a male to produce fertile eggs, one insect can found a thriving colony all by herself, scattering some 200 eggs at random during her brief lifetime. These fall to the ground and hatch into little nymphs, food for birds and wasps. But those that survive have only to climb the plant from which they fell to start eating the right kind of leaves.

Eye on nature

When winged ants were in abundance on a balmy afternoon in Cork city on August 7th, why were flightless ants frantically criss-crossing the ground above their colonies at the same time?

John Mullins, Wilton, Cork

In summer, the worker ants rear males and queens, all with wings, but keep them underground until climatic conditions trigger the nuptial flight. The males die soon afterwards and the mated queens return to earth, rub off their wings and go back underground, where they lay eggs for the next 10 or 20 years. The workers remain earthbound and prepare nests for the newly mated queens.

While hill walking in Donegal I noticed numerous gelatinous, slightly green globes on the bed of a pool. They ranged from 1-7cm in diameter. There appeared to be debris trapped within them.

Michael Cunningham, Castletown, Co Donegal

They were a blue-green alga called Nostoc found in shallow water at the edge of lakes, ponds or pools. It also occurs on land where it swells up when it rains.

While walking along the north side of the Silver Strand in southwest Mayo, I saw a mink on the rocks above the sea.

Cathy Staunton, Lecanvey, Co Mayo

Michael Viney welcomes observations at Thallabawn, Carrowniskey PO, Westport, Co Mayo. Email: viney@anu.ie. Include a postal address.