Beetles on Ivy
Common ivy, Hedera helix L, is generally abundant throughout the UK although rather less so in certain parts of eastern England and across Northern Ireland, there are several subspecies including ssp. poetarum (Bertol.) Nyman (Yellow-Berried Ivy), which is very rare and known only from southern and central England, and ssp. canariensis (Willd.) Cout (Canary Ivy) which is a colourful ornamental variety widely cultivated in parks and gardens but also occurs commonly in the wild. Several other species also occur in the wild; Atlantic Ivy (H. hibernica (G. Kirchn.) Bean) is widespread north to Orkney but sporadic and missing from much of southern and eastern England while Persian Ivy (H. colchica K. Koch) is widespread but very local, occurring mostly across central and northeast England and southern Scotland, and Algerian Ivy (H. algeriensis Hibberd) is known from a few scattered sites north to Glasgow. Because ivy is a very popular and versatile ornamental shrub which is also used extensively in floral decorations, and because it has been bred over the centuries to produce a very wide range of varieties, many of which are vigorous and invasive, a range of different species, subspecies and varieties may be found in the wild across the UK but, of course, especially in urban situations.
Common ivy, Cassiobury park, Watford
Common ivy may be identified by the small, deeply lobed palmate leaves which tend to be more rigid when mature than those of other species, and the colour and shape of the pubescence along the stems and petioles, but species of ivy in general are often difficult to identify because they have been extensively hybridized and bred for certain characteristics, many of these will be found in the field but apart from the bicoloured and (e.g.) deeply lobed forms-which are obviously artificial-all are instantly recognized as ‘ivy’ and most are worth investigating. In the wild ivy is essentially a woodland plant that is well adapted to climb trees and tolerate low light levels, it is vigorous and easily propagated from stems or roots and will thrive in a wide range of soil conditions, thus it also grows on cliffs etc and is ideally suited to the urban landscape. Ivy will be found on waste ground and trees almost anywhere, it produces abundant and luxuriant foliage from ground level to the very tops of trees, sometimes more than 30m from the ground, it is evergreen and the leaves persist through the summer even when extensively shaded by the host tree. Climbing is facilitated by the stems producing rows of numerous small aerial roots which are able to invade bark and other surfaces and provide a very tough anchor points, these also grow when the plant, or parts of the plant, become dislodged in storms etc. and fall to the ground, hence the soil around fallen trunks or boughs may become covered in a dense tangle of ivy stems and foliage. Growths continues year-round but is most obvious in spring and early summer when pale soft foliage is produced from numerous buds along the length of the stem and side shoots, stems and shoots are therefore rich in sap and attractive to certain insects. Flowering occurs in late summer and autumn, usually high-up on the plant where they are exposed to light but often easily accessible where the height of the plant is restricted as it grows on fences, walls and shrubs etc., they are small, 3-5cm across, but arranged in numerous umbels on long slender flower stems and so exposed ivy can produce spectacular flower displays. Small round fruits form in late autumn and ripen to dark purple or black during the winter, they are somewhat poisonous to humans but are an important food source for many birds and as each contains up to five seeds they are readily dispersed and fertilized over a wide area.
When sampling ivy for beetles it will soon become obvious that older specimens of common ivy with abundant foliage are the most productive, especially where these are growing on a series of adjacent trees and where at least some are exposed to the sun for part of the day. Plants may be swept or beaten but the best way to sample them is to hold a net or tray low down under dense foliage and run a stick up and down through the leaves, this produce beetles by day or night and will often produce species not specifically associated with ivy as the evergreen foliage provides shelter for a wide range of insects. Similarly the flowers, which are very rich in nectar, will attract a range of insects in the autumn that might otherwise be difficult to find. Beetles generally associated with ivy include polyphagous species such as the weevil Liophloeus tesselatus (Müller, O.F., 1776) as well as monophagous species such as the bark beetle Kissophagus vicinus (Comelli, 1837), aphid predators such as various ladybirds will often be found on ivy and one species, the small pubescent ladybird Nephus quadrimaculatus (Herbst, 1783), is strongly associated with ivy although it will occasionally be found on other trees and shrubs. A host of other species may be found when beating ivy; these may be saproxylic species associated with the host tree or simply species sheltering among the foliage e.g. tiny cantharids of the genus Malthinus Latreille, 1806 as well as various species of Latridiidae often appear in the beating tray, and if there is any fungus growing among the ivy an even larger range of species will be found.
Some of the beetles likely to be found on ivy are as follows:
Various aphidiophagous ladybirds, but among these often the Harlequin, Harmonia axyridis (Pallas, 1773), Seven spotted, Coccinella septempunctata Linnaeus, 1758, Two-spotted, Adalia bipunctata (Linnaeus, 1758) and Ten-spotted, A decempunctata (Linnaeus, 1758) will often be found on ivy, and various leaf beetles have been observed feeding on young ivy foliage. Beyond this a range of species might be found sheltering among the foliage or basking on its surface but the following species are more generally associated with ivy and at least some should be expected when sampling stems and foliage.
Anobium Fabricius, 1775 Two species occur in the UK and both are widespread and common across the south. Both are saproxylic with wood-boring larvae, A. punctatum (De Geer, 1774) is widely polyphagous while A. inexspectatum Lohse, 1954 is restricted to ivy.
Choragus sheppardi Kirby, 1819 This tiny fungus weevil is associated with a range of broadleaf trees but will often be found by beating ivy, it widespread across England and Wales though very local and rare outside the south east of England.
Clitostethus arcuatus (Rossi, 1794) a very local and generally rare ladybird, adults and larvae predate whitefly and aphids etc, they have been recorded from a variety of plants and have long been associated with ivy.
Kissophagus vicinus (Comelli, 1837) a local bark beetle of southern England, monophagous on ivy; adults from May until October, larvae develop under bark.
Liophloeus tesselatus (Müller, O.F., 1776) Locally common across England and Wales, adults feed on herbaceous vegetation while larvae develop among roots, often those of ivy.
Ochina ptinoides (Marsham, 1802) Locally common across the south and rarely found away from ivy, adults are nocturnal and may be swept from foliage while larvae develop in older stems.
Ocys quinquestriatus (Gyllenhal, 1810) A small carabid that sometimes occurs on ivy-clad walls in gardens and among ivy on trees etc in the wild, very local to the north of Scotland.
Oedemera femoralis Olivier, 1803 Local across the south, this nocturnal oedemerid often occurs on ivy blossom in the autumn.
Oomorphus concolor (Sturm, 1807) Adults and larvae feed on foliage and shoots of ivy as well as a few herbaceous plants and both stages have been found among litter around ivy-covered trunks. Widespread across the south though very local.
Species found on ivy
Ocys quinquestriatus (Gyllenhal, 1810)
Clitostethus arcuatus (Rossi, 1794)
Nephus quadrimaculatus (Herbst, 1783)
Oedemera femoralis Olivier, 1803
Choragus sheppardi Kirby, 1819
Phloeophagus lignarius (Marsham, 1802)
Kissophagus vicinus (Comelli, 1837)