The Hu-Hu Beetle

Dominion, Volume 26, Issue 88, 7 January 1933, Page 16

The Hu-Hu Beetle

(By J. Drummond, F.L.S., F.Z.S., for “The Dominion,”)

MRS D. BLYTH, Derwent Street, Oamaru, has sent for identification an insect which, she states, is a Christmas visitor, or, at least, has entered her house during the past few years, usually in the Christmas holidays. Several members of the species enter, seek dark places, often under a bed, and leave trails of eggs. Her friends are interested in her entomological visitors, but as none seems to know anything about them, she has asked for their name and for information as to their habits. They are the adult form of fat and greasy hu-hu grubs, which formerly were eaten by Maoris, and which bore large holes in fallen forest timber, particularly white pine and Finns radiate. As adults, members of the species, Prionoplus reticularis officially, are the largest beetles in New Zealand. They are about two inches long. Their costume is dark brown, garnished with lighter markings in the pattern of reticulations. They have long antennae, or feelers, and they are longicorn beetles, of which New Zealand has no fewer than about 240 species. They are nocturnal, flying at night with powerful strokes of their wings. They are very plentiful in most parts of the Dominion in the summer. Hu-hu beetles are easily recognised, and they do not try to hide their identity, or pretend to be what they arc not. In this respect they are unlike some other longicorn beetles, which mimic other insects almost to perfection. Australia has a longicorn beetle, often found on a tea-tree, which has a colourscheme that gives it a resemblance to a wasp. Another Australian longicorn goes further. Its wing-cases are shortened, its long hind legs lie flat along its body without being folded at the tips, and its colour-scheme is remarkably like the pattern favoured by a particular family of wasps. These longicorns not only resemble wasps in appearance, but also visit flowers and move and flick their wings in a manner that characterises those wasps. Even collectors often mistake the beetles for wasps, and it may be presumed that bandit insects, afraid of wasps, think twice before they interfere with these wise and deceitful longicorns. Contrasting with the big hu-hu beetle, New Zealand has several species belonging to a family that contains the smallest beetles known. The largest is hardly two millimetres long, the smallest is one-fifth of a millimetre. The habits of New Zealand’s members of these Lilliputians have not been studied. Like their relatives in Australia, they probably are inquilines, beetles which, although not parasites, live as guests or tenants of ants and termites, sometimes called white-ants. Ants’ nests are tenanted by many species of small

beetles, which, according to Dr. G. 11. Carpenter, of Manchester, return the kindness by doing scavengering work for the ants, or provide them with luxuries in the form of sweet secretions. Australia is rich in ants and termites, and hosts of beetles live with them on that arrangement. Dr. R. J. Tillyard states that these Australian inquiline beetles range from species only occasionally associated with ants and termites up to highly-specialised’forms of beetles that; evidently depend on their hosts for their living. Some seen! to pass unnoticed, or to be merely tolerated. Others are cared (for by the hosts, probably for the sake of a secretion the hosts value. Tins is the-law of the inquilines, but. other species of beetles that live in ants’ nests may be robbers, whose practices are unknown to their hosts. Beetles are much less highly organised than butterflies, moths, bees, wasps ants and flies, but they are very plentiful.’ They send representatives of their order, the Coleoptera, to the uttermost ends of the earth. They are the dominant order of insects, distinctive on account of their forewings, which are not used for flight, but form hard cases that fit close to the body, and cover the hind-wings. Dr, Tillyard states that, in spite of the countless number of beetles, less is known of their life-histories than of the life-histories of any other large order of insects, and that comparatively few complete lifehistories of New Zealand or Australian beetles have been worked out. Almost 200,000 species of beetles have been described. This is about 42 per cent, of all species of insects known; the world’s total probably is about 1.000,000. As many as 17,000 species of beetles have been described in Australia, about -1200 in New Zealand. Australia’s beetle population is characterised by large, showy and beautiful forms. Except for the hu-hu beetle and a few other species, New Zealand's beetles are mostly small, inconspicuous and drab. A few beetles, notably ladybirds, are friends and benefactors of man. Most of them are his enemies, leading attacks on his fruit, grain, stored food and, particularly, his useful timbers. On manuka and tea-trees at this season, the manuka beetle, which favours the wearing o’ the green, usually is plentiful. It is one of the beetles that are troublesome in the adult form, devouring green leaves, sometimes entering orchards and taking fruit. Most destructive beetles do all their damage in their grubby stage. This is the ease with the grass-grub, Odonbria zealandica, which, like the manuka beetle, belongs to the cockchafer group, and with the borers. The grubs of some beetles spend several years underground, devouring roots all the time. Root-eating beetle grubs cause losses estimated at millions of pounds in sugar crops and other crops in the Tropics.