Bees and The Chemistry of Nectar
Biologist Patty Jones is fascinated by how a species evolves to better shape the habits and traits of other organisms around it. Her current focus is on bees and flower nectar, which is a mysterious area.
Plants are not entirely vulnerable to the appetites of insects, and many plants produce nectar to lure insects for pollination purposes. They have some superpower secret weapons at their disposal for when they feel bombarded. For instance, the cardenolides in milkweed are nasty compounds that keep insects from eating the leaves of this native North American plant. It’s a fine balancing act, like being poised on the edge of a knife, where the plant needs pollinators for reproduction but needs to repel them from eating and therefore destroying it. This indicates a high level of intelligence is evident in the plant.
The following video is 2:16-minutes long:
It is fascinating that these very same toxic compounds are also present in flower nectar. This means the sweet reward is chemically produced to both attract and repel. Jones, Assistant Professor of Biology at Bowdoin College in Maine, is trying to figure out this contradiction, along with Anurag Agrawal of Cornell University, her research partner. They recently received over $500,000 funding for this new investigation into the complex interactions between milkweed and pollinators, from the National Science Foundation.
Little is known about nectar chemistry, even though the pollinator-plant relationship is vital to food and ecosystems around the world. Jones says it is a complex substance that often ferments, adding alcohol or ethanol to the other ingredients which are amino acids, yeasts, fructose and sucrose.
There is speculation that some nectar types may keep bees healthy, and if this is so, understanding more about it is vital in this age where so many bees are in decline. This video is 2:45-minutes long:
Jones has three hypotheses about Nectar and Toxicity.
First, she is exploring why nectar contains toxic compounds. It is possible that in low doses, these substances don’t hurt bees and may prevent nectar from fermenting. Alcohol may not stop a bee from drinking the nectar but could change bee behavior. Bees tend to seek out and stick with chosen flower types, and plants enjoy this loyalty because they know their pollen will go to the right species. Jones is experimenting with colonies of bumblebees, training them to forage on blue or yellow dishes, so she can observe their behavior and potential problems from the effect of alcohol.
Another hypothesis Jones has is that the alcohol or the toxic substances modify bee behavior in ways that are beneficial to the plant in the same way caffeine does in coffee flowers and citrus flowers. Since the caffeine consumed by bees visiting the flowers helps them remember the scent of that flower better, it probably increases the pollination rate of the plant and is beneficial to the plant.
Her third hypothesis is that the nectar compounds are not toxic to bees, but medicinal, and alleviate gut parasite problems that is a factor driving bee decline. They may be self-medicating and therefore prefer plants with that chemistry that soothes their tummies. This would work out well for the plants, with loyal pollinators.