Small coppers feed on the nectar of wildflowers such as fleabane, daisies, thistles and buttercups
The soldier beetle is a gardener’s friend, eating aphids and many other soft-bodied insect pests
Kew’s many and varied insect pollinators are out in force, as the summer’s flowering begins in earnest. Sandra Bell selects some of her favourites to look out for around the Gardens
In one of the special displays at Kew this summer to celebrate the International Year of Biodiversity, you’ll be able to enjoy tropical butterflies flying free in the north end of the Princess of Wales Conservatory. Insects are hugely important as pollinators throughout the world – moving pollen from one plant to another of the same species, enabling the production of healthy seeds.
Many plants bear pollen in abundance, sacrificing some as food for insects in the certainty that enough will be transferred as they travel from one flower to another. Pollen is also a rich food source for many other organisms unconnected with pollination, such as the communities of lichen on the brickwork of the Aquatic Garden at Kew (next to the Jodrell Laboratory) that benefit from the clouds of pollen from the nearby eucalyptus trees.
After you’ve enjoyed the tropical butterflies in the Conservatory, take time to step outside to find the wild native butterflies that abound at Kew. They are every bit as colourful and varied as their tropical relatives, equally important as pollinators and not too difficult to find if you know where to look.
The holly blue butterfly is a delicate powder-blue in colour, on both top and underwings, appearing almost silvery in flight. It is widespread in the Gardens, especially along Holly Walk during May and June, when it lays eggs on the buds or flowers of holly. Wait for one to settle and you may be able to approach quite closely and watch the eggs being laid among the flowers.
The small copper also flies in May and June and, although it’s a close relative of the holly blue, it looks very different, having bright orange upper wings and a wide,
scalloped margin of orange over the brown of the hind wings. They often feed on cow parsley (Anthriscus sylvestris), stepping through the profusion of pollen as they probe for nectar, and carrying the pollen to another umbel when they take flight.
The purple hairstreak is also closely related to the holly blue, and very different again. At first sight their wings appear to be an unremarkable lilac-grey, but when the sunlight catches them they flash iridescent purple. The underside of the wings is crossed by a thin, jagged, white line, from which all the hairstreaks take their common name. A great place to see purple hairstreaks is from Kew’s Xstrata Treetop Walkway, as they spend sunny summer days fluttering in twos and threes around the tops of the oak trees. They also descend to ground level to feed on bramble flowers in the Natural Areas (see p38).
52 l KEW Summer 2010 Bold red patterning warns predators that cinnabar moths are very unpalatable
Its large size and iridescent colouring make the rose chafer easy to recognise
Adult holly blue butterflies are on the wing during early and late summer
Like butterflies, beetles of many kinds also enjoy cow parsley and it’s rare to find an umbel without spotting at least one or two. Some come for the pollen or nectar, and others, like the soldier beetles, come to catch the pollen-eaters. These are colourful beetles with coral-red legs and head, and brown wing cases tipped with black. They stalk rapidly through the flowers, dragging the pollen with them as they search for smaller insects or their eggs, pausing only to devour their prey as they go.
With around 350,000 species worldwide, beetles come in many sizes and a dazzling array of colours and patterns. Most of our native species are relatively small, so the first appearance of the much larger rose chafer each year never fails to surprise. This beetle is 1–2 cm long, scarab-shaped and so bright that for a moment you might be fooled into thinking that a jewel has been lost among the plants. Its wing cases are usually a metallic emerald-green, but as the light catches them they flash the colour of brass or gold. In fact rose chafers are so improbably large, colourful and metallic that they don’t seem natural at all. By day they rest on tall grasses or lumber slowly among the flowers of hogweed (Heracleum sphondylium), dragging the pollen along under them. Adults can emerge as early in the year as May, but more are seen in June and July. As their name suggests, they are known to eat roses, but at Kew they’re more often seen on wildflowers.
Midsummer is alive with the hum of honeybees and bumblebees. As they busily fly from flower to flower, taking much-needed nectar and pollen to feed themselves and their young, they inadvertently move pollen between the plants, enabling them to set seed and complete their lifecycles.
Moths abound in the summer too, but most fly only at night and are not often seen by day. The day-flying species can be as brightly coloured and intricately patterned as any butterfly, both as adults and larvae. Look in the meadow near the Badger Sett for the cinnabar moth. The adult has wings of an iridescent greenish-black, barred and spotted with red, while the larvae, which feed on common ragwort (Senecio jacobaea), are striped in yellow and black. The bright colour combinations of adult and larvae serve to warn birds that they are extremely unpleasant to eat, since they absorb toxins from the ragwort and put them to good use to defend themselves.
The meadow is also home to the burnet companion moth, which flutters from underfoot when disturbed, revealing bright yellow stripes on the underwings below wavy lace-like lines of brown, white and grey.
As summer passes into early autumn, ivy will begin to flower and will be immediately alive with insects. The second generation of holly blue butterflies will lay their eggs among the buds, while hoverflies, bees, wasps and hornets will swarm noisily among the pollen, feeding urgently during the shortening days. They seem only too aware that the bounty of the summer’s flowers, and their work as pollinators, is almost at an end. n
Sandra Bell is the wildlife recorder at Kew
Find out more about Kew’s Natural Areas on p38, and see p60 and www.kew.org for details of all the events at Kew and Wakehurst this summer
KEW Summer 2010 l 53