This is the third in a series of blog posts from Whitties studying on Whitman’s Crossroads: Pollination Biology in Sweden program this summer with Professor Heidi Dobson. Gareth Jones ’19 is a biology-environmental studies major.
For my blog post, I thought it would be great to provide some insight into one of the major projects assigned over the course of this Pollination Biology class. These work-intensive projects give us (the students) an opportunity to apply what we’re learning in the classroom to a “real” situation in the field and, simultaneously, allow us to practice professional methods of data collection and presentation. In many ways, these reports are an embodiment of what this course is about.
During our five weeks on Öland, we will do three partner projects and one independent final project. In general, we are responsible for the following steps for each project: selecting an appropriate plant species within biking or walking distance, researching the chosen plant, conducting different experiments in the field and observing/recording results over a period of several days. After data collection is complete, we deliver a brief presentation to the class explaining what we discovered in researching our plant and the results of our study. Finally, all of the information listed above is put into a well-manicured report.
Here is an example of a project introduction that blends research and observations in the field in order to provide a detailed description of the selected species:
“The plant Lonicera caprifolium of the family Caprifoliaceae, commonly known as the honeysuckle, is a woody perennial native to Europe. In general, L. caprifolium is a strong-growing, twining deciduous shrub that can reach a height of 4-8m after a period of 5-10 years (Plans for a Future 2017). The leaves are oval, blue-green and approximately 4-6cm in diameter. Most notably, this species is distinctive among Lonicera for being perfoliate, meaning that the upper leaves extend at the base to encircle the node, so that the stem apparently passes through it (Royal Horticultural Society 2017). The flowers of the plant grow in clusters of 4-7 and are attached at the node of the circular leaves. During the budding phase of flower development, the 4-lobed, zygomorphic petals are deep pink and fused together to form a 3-5cm tube terminating in an enclosed pod that encases the sexual whorls (NatureGate 2017). As the flower matures, the pod swells slightly and the external color slowly transitions to lighter hues of white, pink and yellow. Upon anthesis, the fused point at the tip of the flower rips and the petals peel backwards, exposing 5 stamen and one protruding green pistil. The newly inverted petals give the flower face a light cream color, while the outside remains light pink. When the anthers dehisce, their smooth surface explodes like a burst corn kernel and covers the tip of the stamen with a yellow fuzz of pollen. Later, the stigma of the pistil enlarges slightly and becomes sticky, advertising that it is ready to receive pollen. At this point, the hermaphroditic flower is completely sexually active and has the scent to prove it — the common name “honeysuckle” is a reflection of the strong and sweet scent. L. caprifolium is most active in the late afternoon and evening.”
Next, we outline the methods and results of the study using text, photos, tables and graphs. Here is example of each:
TEXT: Time of anthesis (flower bloom)
In general, the flowers of L. caprifolium begin to enter anthesis during the early afternoon and late evening. As shown in Table 1, the calculated average time of anthesis occurs around 18:16 — however the observed times ranged from 17:00 to 19:00. At the research site in Öland, Sweden, sunset during the month of June typically isn’t until 21:30. Therefore, anthesis routinely occurred well before nightfall. A large amount of daytime pollinators (i.e. Apidae bumblebees) were observed buzzing between flowers near the time of anthesis.
Example of bagged inflorescence of Lonicera caprifolium.
Finally, the discussion allows us to interpret results, think about future studies and mention curious/unexplained phenomena observed over the course of the study. Here is a brief excerpt:
“One potential hypothesis for the nocturnal sexual behavior of L. caprifolium is that the late hour of bloom it allows the plant to maximize pollination by nocturnal moths while simultaneously reducing the risk of diurnal parasites. This theory is generally applied to many types of honeysuckle within the Lonicera genus. Additionally, the abundant nectar at the base of the tubular petals corroborates the idea that L. caprifolium is adapted to serving a guild of nocturnal lepidoptera. By the day after bloom, the petals have turned yellow and wilted, perhaps indicating to future pollinators that the flower is no longer supplying rewards. However, the old petals remain on the flowers for several days. This could be done to increase attraction to moths, since old flowers will often be clustered with new flowers or buds. It was difficult to find any scientific literature pertaining specifically to the phenology of the species L. caprifolium, and therefore this research is an important first step in gaining a detailed knowledge of the plant’s sexual development. It would be very interesting to pursue two observations recorded during the study: first, is there an abiotic stimulus that prompts anther dehiscence? And second, is autonomous selfing a prevalent mode of sexual reproduction for for L. caprifolium? Hopefully, more studies will be done to solidify the basic timeline of sexual development charted in this study, in addition to exploring other topics like the two mentioned above.”
Hopefully, this gives you a sense of the kind of work that goes into the projects of this course! I have found these reports to be incredibly interesting and formative experiences. This kind of work is why the idea of a Pollination Biology course was so attractive to me – not to mention the beautiful scenery and amazing cultural excursions that I’m sure my fellow students will write about in their blogs!