Bee Orchids have some of the most fascinating and wonderful flowers of all plants in Ireland. They are relatively rare, but have been recorded popping up in the most unlikely sites recently – e.g. on roadsides where regular mowing regimes have been changed (e.g. from Co. Cork and Kerry in 2020), and in sites managed according to the All-Ireland Pollinator Plan (e.g. in Waterford). In fact, my motivation to write this blog was a photo sent to me by former postdoc Ruth Kelly, who just found a specimen in a scruffy site next to a railway line in Co. Armagh, and my mum, who has them growing in her 1970s housing estate lawn!
The unusual looking flower that gives this plant its name (Ophrys apparently comes from the Greek for “eyebrow” and apifera from the Latin meaning “bee-bearing” or “bee-bringing”) has evolved as as a result of its pollination system, which relies on sexual deception. The flower looks, feels and smells like a female bee (to a male bee) who is attracted, and attempts to copulate with the flower. In doing so, he unwittingly picks up a packet of pollen (orchid pollen is packaged into pollinia), and when he gives up on the current flower, and moves on to be deceived by another, he transfers it. Hence the plant disperses its pollen to other bee orchids. This pollination mechanism is known as “pseudocopulation”.
Although the Ophrys apifera flowers doesn’t look, feel and smell like bee to us, it does give enough “female bee” signals to fool the males – the “furry” texture of the rounded lower petal that looks and feels like a bee’s abdomen whilst she forages from the pink bloom, and the iridescent patterns that catch the light in a similar way to the folded wings of a foraging bee. Each of these signals on their own may not fool a male bee, but the flowers also emit a scent that mimics the female pheromones (see the wonderfully titled paper by Florian Schiestl “Orchid pollination by sexual swindle“). And this is what seals the deal. In fact, research has shown that the scents emitted by a closely related species (Ophrys exaltata) are not a perfect mimic of the female bee pheromones, but are actually more attractive to the male bees than female bees themselves!
The genus Orphys contains a broad range of species across Europe, north Africa and western Asia, each of which has evolved specific signals to attract particular species of insect pollinator. The only other species from this genus present in Ireland is the Fly Orchid Orphys insectifera, which is found in a limited number of calcareous wetland sites (fens, peaty depressions in limestone pavements, and turloughs) in the midlands and west of Ireland (in England it’s found more often in woodlands and scrub) and, despite the name, attracts digger wasps to its flowers.
The Bee Orchid Ophrys apifera is widespread in central and southern Europe, but at their northern limits in Ireland and Britain. And here in Ireland, where flowers appear in June and July, we don’t have the bees that these orchids have evolved to fool (solitary long-horn bees, Eucera longicornis). So instead, this species has evolved the ability to self-pollinate in areas where the pollinators are not present. This occurs as the pollinia (the yellow blobs hanging from the top of the flower entrance) swing freely and either contract or bend as they age, or a gust of wind can blow them onto the stigmatic surface (as in the picture above).
Bee Orchids long been know from botanical hotspots like the Burren in Co. Clare and Bull Island in Dublin, and this perennial species tends to be found in open, semi-dry grasslands on limestone, and calcareous dunes. It’s a protected species in Northern Ireland, but not on the Floral Protection Order in RoI. Bee Orchids colonise sites disturbed by human activity, like roadside verges, old quarries, gravel pits and in urban settings. They prefers open habitats, and are out-competed by shrubs and trees if a site becomes overgrown. Thus to maintain populations of Bee Orchids, mowing or grazing needs to occur at the end of the season, and the cuttings removed.
Like many orchids, Bee Orchids form symbiotic relationships with mycorrhizal fungi, which extract nutrients from the soil and transfer them to the plant via its roots. The use of fungicides could reduce the prevalence of these mutualists, which may limit where the bee orchids can grow. Other pressures on Bee Orchid populations include ploughing of grasslands, and if mowing occurs during flowering or before the tiny, wind-dispersed seeds have formed and been released, populations can decline.
Despite their remarkable flowers, the plants can be easily overlooked unless you are looking for them. But because the flowers are so bizarre, and can’t be confused with anything else, Bee Orchids can excite even the least botanically minded people.
Edit: coincidentally this wonderful video by John Feehan was published on the same day as this blog – part of the Wildflowers of Offaly series.
About the author: Professor in Botany, Jane Stout leads the Plant-Animal Interactions Research Group in Trinity College Dublin, and teaches botany, entomology and plant-animal interactions to undergraduate students.