My favourite British orchids are the ‘insect mimics’ which dupe insects in to copulating with their flower heads as a method of pollination (some of the pollen sticking to the insects body being transferred when it visits other plants). The flowers not only mimic the physical appearance of insects but produce scent which resembles the sex pheromones released by the pollinators. In the Midlands the only widespread species is the Bee Orchid. As a safeguard mechanism the ‘mimics’ are able to self-pollinate and were they not the Bee Orchid would be absent from the UK as the bee species it exploits does not occur here. I am reliably informed by Brian Laney, the fount of all botanical wisdom (well mine at least), that they can often be found on mown areas where they frequently fail to flower in the short space of time between cuts. To locate them in such circumstances requires identification of the basal rosette, not to mention ample time and the inclination to scour the lawns bordering units on industrial estates. I will leave this to Mr. Laney but I do occasionally find flowering plants, usually in rough grassland which is not so dense as to ‘crowd’ everything else out. I discovered the plant in the photo below whilst conducting breeding bird surveys on an old colliery face near Measham in Derbyshire.
Bee Orchid, Measham, Derbyshire
In Warwickshire we are fortunate enough to have a colony of the Bee Orchid variant known as the Wasp Orchid which is scarce in the UK. There are structural differences between the ‘wasp’ and ‘bee’ flowers and I find it puzzling that both can apparently occur on a single plant.
Wasp Orchid, Warwickshire, by Martin Elliott
We are even more fortunate in that the county also has one of the few sites in the UK for the Bicolor Bee Orchid variant.
Bicolor Bee Orchid, Warwickshire
The population is a small one with 2-3 plants typically flowering on roadside embankments and traffic islands and this year only a single flowering plant has been seen. Fortunately the site is managed, though it is not a local nature reserve, and supports fairly large numbers of Common Spotted and Pyramidal Orchids and other species such as Yellow-wort which are far from common in Warwickshire.
Research detailed here http://www.sciencedaily.com/releases/2009/12/091217183442.htm has established that whilst the ‘insect mimic’ orchids reliance on ‘pseudocopulation’ reduces the number of insects which will visit them as they are attractive only to males of a particular species, the strategy pays off as the efficiency of pollen transfer is increased. More pollen is transferred from one flower to another by ‘psuedocopulation’ than is transferred by insects travelling between flowers to feed. Unfortunately, as is often the case in evolutionary biology, increased specialism may ultimately make life difficult, or even untenable. The Early Spider Orchid flowers a month or so before the Late Spider Orchid but research has shown that it is no longer flowering early enough. Flowering in the Early Spider Orchid is timed to coincide with the emergence of its principal pollinator the Solitary Bee. Research outlined here http://www.theguardian.com/environment/2014/nov/06/climate-change-is-disrupting-flower-pollination-research-shows used specimens held by the British Museum of Natural History (BMNH) to assess period changes in the flowering of the orchid and the emergence of its pollinator over time. It was found that whilst both showed evidence of a reaction to climate change which brought them forward they did not respond equally. The emergence date for the bee has come forward by more days than the flowering date for the orchid leading to a mismatch. The problem is compounded by the fact that female bees which used to emerge later than males now come out earlier reducing the likelihood that males will visit orchids.
To see either of the Spider Orchids in the UK it is necessary to visit the south coast and I recently had the opportunity when I accompanied Brian on a trip to Sussex.
Early Spider Orchid, Sussex
This trip made me all the more determined to see another of the ‘insect mimics’ which can be found closer to home. The Fly Orchid can still be found in Northamptonshire but recent records come from just two localities. Throughout the UK this species has disappeared from many woodland edges and it is interesting to note that it has done exactly that at one of the remaining sites in Northamptonshire where searches by Brian Laney found none along the roadside where it formerly occurred but a number of flowering spikes under the trees a short distance in to the woodland.
Fly Orchid, Northamptonshire
I had hoped to finish this piece off with an account of a trip to Kent to see the only full species of British insect mimic I have yet to encounter, the Late Sider Orchid. I now suspect that a late flurry of work and a commitment to a long cherished ambition to visit Salisbury Plain in search of Pheasant’s-eye mean that it will have to wait for another year. I will edit this post if I make it.