You might think that it is stretching a metaphor to compare any garden insect to a hippopotamus. But clearly, you haven’t seen the rose chafers on my patch of sun-drenched ground elder down here in the deep south.

It’s not so much that these solidly built beetles come to feed on the pollen and nectar from the delicate umbels, it’s more that they come to luxuriate. They land heavily upon the white, icing-sugar-soft florets and crawl around as if wallowing in a foam bath, all the while looking inappropriately large, like an adult human among the plastic balls at a soft play centre.

Rose chafers are brilliant, bejewelled, 2cm-long marvels that in summer fly from flower to flower and shrub to shrub like enormous bumblebees, far more at home in flight than the gangling stag beetle. When the sun catches their elytra (hard wingcases), the green shimmers and dazzles, as if the result of a long session of brass-rubbing – perhaps too hard, as the flaky white lines and dots that appear on the wingcases may suggest overzealous attention: the chafer chafed.

Rose chafers are the enviably good-looking relative of the dowdy but lovable cockchafer, or May bug. Or perhaps they are the midlife crisis May bug, trading a tired brown overcoat for an embarrassing flashy green suit. Either way, they look too “tropical” to be British insects, too sun-loving for a rainy nation. Perhaps it is no surprise that they are commonest in southern England.

These glorious insects provide definitive proof that every garden should contain rotting wood or a compost heap, or preferably both. The adult female lays eggs in such places, and the grub-like larva lives in the rich subterranean soup for two years before pupating. The adults emerge in autumn but remain underground until they emerge in the warmer months, diamonds from the decaying seams.

The adults have a brief summer of sex and sweet food. They have specially adapted mouthparts, which somewhat resemble a wet brush, and take up pollen easily. It is a life of ease, of revelling and revelry, balanced on blooms.