At this time of year I love to watch the sun-oriented movement of my garden. By this I mean the way in which our oxeye daisies and cat’s-ear flowers turn in relation to the same source.
In what you might call their dormant state, at about 8am – when the day is bright but temperature neutral – the flowers of both, as well as most of my yellow rattle blooms, are all pretty much oriented north-east. Then, as the day fires up, the daisies and cat’s-ears drop their heads and tilt due east the better to catch the light.
Slowly, as the sun “rises” to its zenith, the two plants make completely separate responses. It’s most dramatic in the cat’s-ear, because, come 2pm, what was a swaying constellation of 100 golden spheres at the tea break at 10 have all closed. The oxeye daisies, meanwhile, are standing bolt upright as if each innocent open head were linked by thread to the star directly above them.
As I log this physical movement, so can I also chart a temporal odyssey during the same span. Because the flowers attract a perpetual awkward ballet of bumblebees, mainly early, tree and white-tailed. Among them are several hoverflies, including Volucella bombylans, known as bumblebee hoverfly, and Merodon equestris (large narcissus fly), which are both mimics.
V bombylans looks roughly like a white-tailed bumblebee and the narcissus fly looks something like a tree bumblebee. Essentially, by wearing the aposematic colours of unpalatable, sting-possessing bees, the defenceless flies gain a selective advantage.
Who knows how long the copycat colours have been helping hoverflies to avoid predation? We do know, however, that the earliest fossil records for bees are from the Cretaceous, when dinosaurs roamed. The lookalike traits in the hoverflies will have evolved afterwards but almost certainly you are seeing a heritage in those hoverflies that long predates a time when mammoths and woolly rhinoceros were hereabouts in Norfolk.
