In Cuericí, a species of plant grows high on the mountainside, occupying light gaps and canyon walls. Its hanging bell-shaped flowers look like light orange fairy skirts swinging from the vines, dusted with thin peach fuzz from petal to the base of the plant. Unsuspecting passers-by (or more particularly, people named Gillian Britton) refer to them as “Tinkerbell flowers,” and admire the hummingbirds that come to drink the plant’s nectar.

Be warned. The tinkerbell flowers are sneaky for several reasons:

1. They escaped my every attempt to key them out even to family (!), and remain unidentified until possibly this afternoon, when I will consult a botanical expert and his entire herbarium

2. They are occasionally full of tiny flies (up to 430 in one flower) and nobody knows why

3. The tiny hairs on the plants are actually EVIL HYPODERMIC NEEDLES full of MEAN NASTY CHEMICALS that want to make you VERY SAD

So of course, presented with these facts, I (along with Colleen and Tyler) decided to embark on a research project exploring the potential hypotheses to explain the presence of these tiny flies. It felt like such old-school biology- unidentified plant, unidentified flies, little specific knowledge of the study system, and a LOT of back-breaking work to make the leaps of knowledge we needed for understanding of this system. It was like detective work, under a microscope and in the field, contemplating flowers and flies while wincing from the lines of painful bumps we’d earned by errantly touching a leaf or stem. 

I think it was probably the best and most interesting science I’ve done so far. Taking apart the flowers and leaves to better understand them, looking at fly morphology, and extrapolating from the sizes and shapes of plant parts the life history of the entire organism… it was actually and non-ironically thrilling. 

Best as we can figure, the picture stands thus:

Flies are not, as previous groups had hypothesized, using the flowers as greenhouses to warm themselves in the mornings. Though the flowers do, indeed, warm up significantly more than their surroundings when hit by the light, the flies weren’t aggregated in warmer flowers either in the morning or the evening. 

There was little evidence for mating gatherings of any kind, as the sex ratio of the flies in the flowers (another adventure in microscope use and fly-sexing knowledge left over from my genetics class) seemed random.

But our most astounding result was that the flowers were protandrous, meaning the male parts that bear pollen matured first when the blossom was young, and the female parts became fertile after the pollen from that flower had been dispersed (flowers often use this as a strategy to avoid accidental self-pollination). The process of the flowers’ maturation corresponded to the growing female portion of the flower, which takes the form of a “style,” an extended tube that reaches into the flower’s ovaries. We found huge aggregations of flies almost exclusively in flowers that had very short styles, meaning that the flies preferred to aggregate only in young male flowers. The trend was both striking and completely unexpected- it was just a stroke of genius observation on Tyler’s part that led us to measure style length at all.

In this picture, the style is the green part visible on the right half of the dissected flower. The anthers/pollen-bearing portion are the long, thin strands topped with little black or green dots. 

I don’t know if anyone but me finds this incredibly exciting, but I have so many more questions about these plants and what the heck those flies are doing in there. Nectar-gathering while the plant is young? Seeking shelter and using the plants’ urticating spines as protection? Pollinating? Mating? Resting? Do they benefit the plant at all? SCIENCE!