Another native Colerne orchid for this week and another fabulous photo from Andrew Dawson who found it. It is on Wiltshire’s rare plant register so you will understand why I don’t mention location. They are plants of open woodland edges and limestone grasslands so scrub encroachment, closing of canopies as coppicing traditions lapse, and increased grazing by deer all threaten their survival.
The flowers resemble a fly sitting on a green flower, with thin upper petals mimicking antennae and a silver fly wing patch. Despite the name, pollination depends entirely on tricking two species of digger wasp, Argogorytes mystaceus and Argogorytes fargeii to visit by releasing scent mimicking female wasp pheremones. The male wasps emerge first giving time for multiple visits to transfer pollen before the “real thing” arrives. Sneaky!
This ancient, but very close relationship intricately links the plant’s survival to the fate of its digger wasps. They need bare ground to dig their nests and, it goes without saying, an environment free from the pesticides which will kill them. Adult digger wasps visit Apiaceae flowers such as hogweed and wild carrot for nectar whilst their larvae feed on nymphs of froghoppers and spittlebugs. How carelessly we disrupt these very ancient relationships leaving a legacy of loss we hardly take time to notice.