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The Fieldwork Edition

Having spent the winter months adjusting and refining my camera equipment and practicing using the software, I suddenly found myself in a whirlwind of fieldwork from the middle of March until the middle of July. While I expected the fieldwork season to be a little rushed (each Ophrys species provides a window of opportunity to collect data of only around 2-3 weeks), I was not expecting the combination of a late snow and a very hot, dry Summer to compress the flowering period quite as much as it was. I've been reliably informed that part of a PhD is learning to adapt to change and readjust plans. Probably more than once.

But I can hardly complain, being outside enjoying the beautiful weather at gorgeous sites like this:

The first species I became acquainted with was Ophrys sphegodes, the Early Spider Orchid. Apparently, the flower with its distinctive 'H' marking looked a lot like a spider to 17th century botanists. If I squint a little I can kind of see what they mean.

In my search for this orchid, I found myself at Samphire Hoe in Dover during a cold, windy March day. Then it started to rain. When it was forecast to be sunny all day. I was unprepared and got quite soggy! I was just about to give up my search when I spotted my first one, and was suitably elated. Then surprised. I was envisaging flower spikes as tall as the ones I'd seen on O. apifera, the bee orchid, the year before. Many of these were barely 20cm tall, and the flowers themselves are smaller than a 20 pence coin.

Once I had my 'eye in' I then started seeing them everywhere. Delighted, I made notes and returned a few times after that to collect data on them.

It was after this that the next three species all decided to flower in unexpectedly quick succession. The fly orchid, O. insectifera, was the most elusive of all, with far fewer than expected flowering at my field sites. However, perhaps simply due to how different they are from the other British species, they are my personal favourite so far! Their spikes are reasonably tall, but they are not much easier to spot than the ESO, owing to their tiny, dark blooms and propensity for growing in long grassy areas.

Again, their common name is slightly misleading, and they are not pollinated by flies at all but rather, look somewhat like flies nestling against the green foliage. This site, Dancersend Nature Reserve, was a wonderful treat for orchids and other wildlife in general, though I managed to stay focused for long enough to get the data I needed for my project!

The final two orchids present in the UK are occasionally confused with one another. And it makes sense that they would look similar when you learn that they share their main pollinator, a long-horned bee, Eucera longicornis. O. apifera, the Bee Orchid, has become predominantly self-pollinated though, and it is uncertain whether they are even still cross-pollinated at all in the UK. O. fuciflora, the Late Spider Orchid, on the other hand, are at the opposite end of the pollination spectrum and may be pollinated by up to 7 different pollinators. They flower at similar times, and LSOs are often found at the same sites as the Bee Orchid. This makes them my academic favourites, with delicious possibilities to unravel some awesome science.

LSOs are very rare and I was concerned that I wouldn't be able to find them at all, but luckily, I managed to find enough to collect some data. As with the Fly Orchids, I am still on the hunt for a second field site for next year. But I am happy for any win, and getting enough data to analyse, no matter how many sites are included, is definitely a win.

The Bee Orchid is the most common of the Ophrys species, and I am lucky enough to have a population of them growing on the Open University campus. This made for some relatively relaxed (if still rather busy) field work days in the sunshine this year. I was interested to note that not only are they more common across a large geographic year, they also seemingly grow in great abundance at a smaller scale. I stopped counting individual plants on the OU campus at 100, and this excludes any individuals that remained dormant and didn't grow a leaf rosette in the Autumn.

Some of the flower spikes grew amazingly tall, and one robust individual reached nearly up to my hipbone. (I am not very tall, but this is still pretty impressive for this species!) There was quite a range though, and some individuals only grew a few centimetres before giving up and withering entirely. The hot, dry spells seemed to affect many of them too, with the topmost buds dying off before ever opening.

There were some unusual patterns on some individuals, as can be seen with the normal patterning (left) and the unusual form present in small numbers at the OU (right).

The male insects rely on scent and vision to find mates, and so these are the attractive signals the flowers imitate to dupe the male insects into attempting to mate with them. The tactile signals used by the flowers, namely, the shape, texture and general feel of the flower are for maintenance of this pseudocopulation behaviour for long enough to transfer pollen.

I am mainly interested in the attractive rather than the maintenance signals, so the data I collected this field season included, photographs in UV and visible light (insects can see in UV, so this is important to understanding what signals these flowers are using), some scent samples, and pollination rates.

The camera set-up needed to be able to get UV and visible photo pairs with as little movement as possible between the photos, and not damage the flowers in the process. So, I have an altered camera, lens filters, a tripod, the GorillaZilla, a Wimberley Plamp II, my visual standards and a sun-shield for the camera screen. It takes a little while to get it all set up correctly, but fortunately the orchids tend to grow in patches, so I can just pick up the whole lot and move from flower to flower.

Scent sampling relies on a 'push-pull' system, where filtered air is pumped through a bag containing the flowers and onto a scent-capturing tube, using a Pye Volatile Collection kit. This kit has two pumps, an air filter and air-flow controllers. Again, it was important not to damage the orchids at all, so the Wimberley Plamp II comes to the rescue again to hold the heave tubes and bag so as to not put any weight on the flower spike.

Now, the data analysis begins over the winter months, while I wait [im]patiently for the flowering season again!

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