HUMMINGBIRDS AND TIGERS
Away from the background of urban and transport noise it is still possible to experience this primaeval mix of chirrups and hums on moorland, in meadows or even a well-planted back garden. Moths are largely nocturnal, seemingly entering our world via the glare of night-time illumination and open windows. Just a few are active in the daytime with two of the most spectacular being the hummingbird hawk and tiger moths.
Like its namesake the hummingbird hawk moth feeds while hovering in front of a flower with the wings lost in a fawn blur. Fortunately for the viewer it will remain in position for some time, often at less than arms length away. Honeysuckle, petunias and especially red valerian (commonly seen growing in walls in the South-West) seem to be their preferred sources of food and we keep several valerian plants close to our patio for this reason. The nectar is stored in long protruding sacs well out of reach of most insects. Even with the naked eye it is possible to watch the moth uncoil its needle-like feeding tube and probe deep into nectar rich florets, working its way round the head of flowers before moving onto the next bunch and returning later as the plant replenishes the supplies. Plant and animal are thus ideally suited to one another. Once seen they are never forgotten and many of our friends now report seeing them in a variety of locations! They are resident in southern Europe and migrate to the UK during the summer, with the warmer summers of 2000 and 2006 being recent peaks.
The garden tiger moth in contrast should be far more familiar, being a resident known from the Middle Ages and with a 1930's plane of the same name! Its caterpillar is the 'woolly bear', 60mm long and covered in long hairs, chestnut below and black above. The adult is slightly shorter but with distinctive wings, brown with a creamy network on the fore-wings while the bright orange-red hind wings show large black warning spots as the insect prepares to fly off. With spots rather than stripes the 'tiger' label seems a bit inappropriate but a close relative known as the Jersey tiger, which has a more southerly distribution does indeed have cream stripes on the fore-wing and did make two brief appearances in our garden during recent summers. Garden tiger moths hibernate as half-grown caterpillars and need reasonably cold winters to avoid waking up too early. Climate change may be reducing their numbers while ironically increasing the number of visiting humming-bird hawk moths!
Even more tiger-like are the gold and black striped caterpillars of the cinnabar, the most common of our day-flying moths. The adults are the pretty pink and black moths that fly up when one is walking through rough grassland. Two common weeds, groundsel and ragwort are the food plants for their caterpillars, both of which have disappeared from our garden. While ragwort was systematically removed around 2003 in a panic reaction to reports of horses dying due to its consumption, in our garden I was able to watch the caterpillars strip these plants down to their bare stalks in a matter of days. Unfortunately early research into their use as a biological control method were inconclusive and the idea seems to have been abandoned. We really do need to learn more about the subtleties of the balance of nature rather than seemingly constantly at war with it!