So what's all the buzz?

July's creamy-white platters of hogweed seethe with hairy bluebottles, each with its shiny, peacock-glint of colour as it tiptoes, dipping for nectar (the males like flowers; the females buzz indoors, flesh-hungry).

I stay to watch: not so much the assorted flashy-arsed familiars of carrion and dung, but the more finely-wrought hoverflies among them, some pretending to be little wasps and others bees. Later on in the month, the hogweed nectar party will be infiltrated by soldier beetles, setting up carnivorous ambushes among the flowers.

Flies, moths, beetles, wasps and butterflies all have species that can be counted among the pollinators of the countryside. And there are close on 200 kinds of bees, most of them small, solitary and short-tongued but feather-legged enough to gather pollen. In the first rank, of course, are the big, social, long-tongued bumble-bees, nuzzling the deep flowers of clover and honeysuckle, French-kissing the difficult "snapdragon" lips of deadnettle, runner bean, sage.

I offer this in some reassurance that, whatever happens to the honey bee now that varroa has reached Ireland, plant life as we know it will continue undisturbed. No wild flower species is likely to die out for lack of pollination. Some commercial crops will yield less, honey production may fall and fruit orchards may eventually miss the services of quite so many hives. Varroa is a damaging plague, but not, perhaps, the ecological disaster proposed in some recent Sunday headlines.

The varroa mite, a bloodsucker, is a natural parasite of the Asian honey-bee, Apis cerrana, which has its own defences against it, the two insects having evolved together. Through movement of colonies and the trade in queen bees, it has spread through the European honey bee, Apis mellifera, since 1970, and has travelled on to America. The western bees have long been separated from their Asian origins and cannot cope with the mite's attentions: a heavily-infested colony may collapse within two or three years. It is reckoned that a quarter of North America's wild and domesticated honey-bees have disappeared since 1990 and that the costs to American farmers (growing almonds in California, for example) are heading for $6 million a year.

Managed closely in hives and treated with selective pesticides, honeybees will get by, pending the breeding of a mite-tolerant bee for temperate climates. Those in the wild will probably decline, or even disappear locally, until the tolerant strain appears. While Apis mellifera suggests a tidy, homogenous, European species of bee, a good many regional races have already been absorbed and refined for beekeeping, and most Irish honey-bees today stem from Italian stocks.

Honey-bees "go wild" when a proportion of workers in a crowded summer hive fly off in a swarm, with a newly-bred virgin queen, to start another colony. An attentive beekeeper will intercept the swarm and recapture it as the nucleus for a fresh hive. But many swarms go free, following their advance scouts to whatever promising cavity they have spotted.

Honey-bees, like bats, have owed a lot to the Big House demesne, with its old, hollow, broadleaf trees, undisturbed roofspaces and warm, dry cavities in masonry. But, with no-one to feed them in difficult seasons, only a small fraction of wild colonies can have reached a perennial equilibrium.

The great efficiency of honey-bees in pollinating food crops lies in their repeated, systematic visits to the same patch of flowers. They will work a single crop or species of flower until the nectar is exhausted, and pack the pollen baskets on their legs until they are bulging with food.

Bumble bees can be just as selective in the flowers they visit (tongue-length has much to do with this) and even more determined in their gathering, sometimes using a special, high-pitched buzz to shake the pollen from difficult anthers. They work faster than honey-bees, for much longer hours and in far worse weather.

But while the honeybee colony overwinters as a cluster of workers with their queen and a store of honey, the far smaller bumblebee colony dies out in autumn, leaving a young mated queen in solitary hibernation, ready to start a new colony in spring.

Getting on for 20 kinds of bumblebee live on this island, half-a-dozen of which are widespread and fairly common. They all evolved together with our native plants and climate, and serve the countryside in ways that the honey-bee, even after so many centuries, never will. If we worry about varroa, we should also be aware of the steadily dwindling supply of habitat for bumblebee nests, most of them in borrowed holes in fieldbanks or the top few inches of rough pasture.

The distributions of the various bumblebees in Ireland are still poorly known, but, group by group, our insects are at last being catalogued as they deserve. The latest are the Braconidae, one of the largest families in the Hymenoptera, the order that includes the ants, bees and wasps. Picture biggish ants with wings and long, long antennae and you have a rough image of them.

Beyond that, you may not wish to think too closely about them, since the braconids, like their brothers, the ichneumon flies, hold a vital job in controlling insect numbers, chiefly by parasitising the caterpillars of moths and butterflies (including, I am happy to say, the cabbage white). They stab the caterpillars with their ovipositors and lay eggs inside them. When the grubs hatch - perhaps 100 or more - they start eating, but are careful not to touch anything important until they want to get out.

The 529 species so far found in Ireland (there are many more to come) are now listed, with their places of collection, in a new publication from the Irish Biogeographical Society, sponsored by the Heritage Council.* An unexpected grace note to all the pages of species and places is a set of four exquisite 19th-century paintings of Irish braconids and accompanying flowers - worth the £5 price, including p&p, for framing in the loo.

Contact Dr Jim O'Connor, National Mu]seum of Ireland, Kildare Street, Dublin 2.