Vanilla and food: not plain when it comes to pollination

You decide to bake some cookies. You have your butter stick ready to go, you open your pantry to look for the ingredients. There is flour, oats, sugar, chocolate chips; things look good. You then realize that you’re missing that one ingredient, the one that makes it all come together: vanilla! Luckily, you can quickly buy some fresh vanilla pods or vanilla extract. In a couple hours you are there, enjoying your cookies and the pretty fall landscape.

This is all good, but have you ever thought how that spice – vanilla – gets to your pantry? And who is allowing for that to happen? In today’s blog, the second in our comfort food series (part 1 is here), we will talk about this spice that is so present in our lives that we may not even think about it. Let’s talk about vanilla and how appreciating it is tightly linked to understanding pollination and the key role of pollinators in our food system.

What is vanilla?

What we consume as vanilla is the fruit and the seeds of an orchid, the vanilla plant. This fruit comes in the form of a pod, and the tiny “dust” that comes off it is the hundreds of tiny seeds that this plant produces in each fruit. Vanilla orchids have a vine habit and in the wild are found clinging to trees in the forests of Central and South America. Considering this natural habit, all vanilla cultivation is done vertically, using different types of support.

vanilla plants
Vanilla orchids have a vine habit, and the pollination of their flowers leads to the development of the pods and the tiny seeds we consume. Photos: M. Paredes, M. Manners, Joy.

Although vanilla is now cultivated in several parts of the world, it is accepted that all cultivated varieties/species are Meso- and South American. Indeed, the plant species had been known to be selected and used by Natives of those regions prior to the arrival of Europeans in the New World, but it is only following that arrival that Europeans created a strong demand for the spice. From this respect, if we can today enjoy our yummy cookies and cakes (and more!), recognition is due to the ancient selection done by Aztecs, Totonac, and Mayas in the current Mexican territories.

vanilla vines and pods with a historical description about use
Each plant produces several pods that are harvested and dried before commercialization. Historical descriptions (here, from 1651) indicate that the plant we know today was cultivated by Natives in current Mexico, who called it “Tlilxochitl” or “black flower”. Images: Hernández (1651), Foam.

Today, vanilla is produced mostly in Madagascar, Indonesia, and Mexico, and is the second most valuable spice in the world (after saffron). Its production, however, experienced a bumpy road and still today goes through regular difficulties, which leads to extreme annual fluctuations in vanilla prices. In fact, vanilla plantations occur in regions regularly affected by extreme weather events, such as cyclones, which can destroy a whole year of production. These events lead to large variations in yield from year to year, leading to crazy changes in vanilla prices, going for example from $20/kg in 2010 to the current $350/kg.

How is vanilla produced?

Although vanilla became a European favorite quickly after it was first introduced to the continent, the production of vanilla pods remained elusive for a long time. Indeed, people realized very quickly that without active transfer of pollen to the stigma of the flower, the flowers would not develop into fruits (see how that works), and thus the much-searched-for vanilla beans would not develop at all!

In fact, after much observation of the plants in their natural habitat, people realized that their pollination required especially the visit of a group of bees restricted to the New World, the euglossines, or orchid bees. Restricted to South and Central America, these bees have strong associations with orchids, from which the males are known to collect floral scents they use for courting females (this is super fascinating, and worth a future blog post). Some species of this group of bees are currently suspected to act as pollinators of vanilla flowers in the wild. During their visits, they passively deposit pollen on the stigma of the flower, which leads to the vanilla bean development. Although these bees do pollinate, flower visits by these bees are not common, so even in regions with bee populations, fruiting rates remain relatively low.

bee approaching a vanilla flower
In their natural habitats, vanilla flowers are thought to be pollinated by beautifully metallic euglossine bees. Photo: Gil Wizen, www.gilwizen.com.

Adding to this, once vanilla was “discovered” by Europeans, it was introduced into a variety of colonial lands, especially to Indian Ocean islands (e.g., Madagascar, the Comoros, la Réunion) and to French Polynesia. However, and because as I said before, the pollinators of this plant are restricted to the Americas, vanilla production was not successful in those regions. Plants would flower, but the lack of pollinators would lead to virtually no pod production. This changed when a solution was found. Indeed, there had been some early attempts to develop human-based pollination methods, which were as complex as impossible to use. It was finally a slave from the Réunion Islands, Edmond Albius, who developed a simple method to pollinate the flowers by hand, helped with a stick and his own fingers. It was only after this method development that vanilla production could bloom (actually, fruit 😉) to reach its current extent.

hand pollinating a vanilla flower
Edmond Albius was the Réunion slave who revolutionized vanilla production, developing the hand-pollination method still currently used today across the globe. Photos: Antoine Roussin (1863), F. and K. Starr.

Although one may expect the techniques to have changed since the first development of this method, the vast majority of today’s global vanilla production is still hand-pollinated following Albius’ technique! In other words, the production of the second most valuable spice in the world is currently based on pollination done by hand. And this is what I wanted to stress today. We hear a lot about the importance of pollinators, but I feel that the case of vanilla is such a clear example of how important pollinators are to maintaining not just food supplies, but also global economies: take the pollinators away and you lose basically the whole vanilla bean production chain and market. Doesn’t that make you feel especially thankful for pollination and pollinators for that great flavor in your cookies?

Happy Thanksgiving to all!

By Anahí Espíndola, Assistant Professor, Department of Entomology, University of Maryland, College Park. See more posts by Anahí.

The buzz in your seasonal latte: Who pollinates the pumpkin spices?

Wow, fall is here. When did that happen?! And because this fall comes after a tortuous year, I want to spend time doing some soul pampering. It is for this reason that, until the end of the year, I will be talking about many of the yummy foods we love and that many times help us through rough times. And to start the series, and matching the fall season, let’s talk about how the spices that create “pumpkin spice” – cinnamon, nutmeg, ginger, cloves – go around getting pollinated and reproduced.

pumpkin spice products
How do you know it’s the fall in the US? We’re surrounded by pumpkin-spice
everything! Photos: PatentingPatch, M. Mozart, J. Kramer, theimpulsiveguy.

As a general introduction to these spices, we have to realize that they all originate outside of the US, and that most of them are even today not produced in the US. This is important to mention because it is humbling to realize how much our food habits (especially those related to comfort foods) are based on foods that are imported by the US. Further, even if that may seem futile, markets for these spices have been historically and are still currently huge, with power over these markets driving major geopolitical clashes, setting the foundations of the current global distribution of wealth, and sustaining (and sometimes undermining) societies around the world.

cinnamon
The cinnamon bark is collected by “peeling” the tree (Photo: P. Nijenhuis). Cinnamon flowers are pollinated by many insects, but several Apis species are particularly important (Photo: D. Valke). Shown are Apis cerana and Apis dorsata visiting other flowers (Photos: Peterwchen, R. Thumboor).

Cinnamon

The cinnamon we eat comes from the bark of cinnamon trees. This bark is either ground or consumed in strips, which are added to savory and sweet foods. Cinnamon trees originate in South Asia and are adapted to growing in wet tropical forests. Today, the most important cinnamon producer is Sri Lanka, and most of the exports go to the USA and Western Europe. Even though we do not eat the fruits of this plant, pollinators play a key role in their reproduction. Cinnamon flowers are poor “selfers,” meaning that they produce the most seeds if receiving pollen from a different flower. These flowers thus rely on insect pollinators for their reproduction (see this post for more details about how flowers function) and among the most abundant species are three Asian “cousin” species of the managed honeybee, as well as some flies.

Nutmeg
Nutmegs are the seeds found in the fleshy fruits of the nutmeg tree (Photo: B. Vauchelle). Nutmeg flowers are very small, pollinated mostly by thrips, and through a deceit-based pollination called “mistake pollination.” (Photos from Sharma and Armstrong, 2013). White bars indicate 1mm.

Nutmeg

The nutmeg we consume is the seed of the fragrant nutmeg tree, which originates in Indonesia. Even though currently it is cultivated heavily in Indonesia and Malaysia, it is also produced in the Caribbean. Because the food we consume is part of the fruit of this tree (there is no nut if there is no fruit), pollination of this crop is central for food production — and this is a super-fun crop to learn about!

Indeed, only some nutmeg trees bear fruit, because half of the seeds of this plant produces male trees (which produce pollen) and the other half produces female trees (which will make fruits and nutmegs). The fun pollination story doesn’t end there, though. The flowers of these plants are tiny, bloom in the night, and need pollinators to transport the pollen from the male trees to the female flowers. So who does this job? A lot of insects! Studies in the species have demonstrated that most pollination is done by tiny thrips, and probably also some beetles, flies, and maybe some bees (here you can read about pollinators other than bees).

But let’s spice up (pun intended) this story! This plant is not only pollinated by uncommon types of pollinators; it also tricks them into pollinating! In fact, the insects are interested only in male flowers, where they can collect pollen they can feed on, and they do not care about visiting female flowers, which do not offer any pollen or nectar. Thus, the strategy used by female flowers to attract pollinators is to trick them by making them assume they are actually male flowers, a strategy known as “mistake pollination”. It’s only after they entered the female flower and deposited pollen on the stigma that the insects realize their mistake.

ginger plants
Ginger plants grow from the rhizomes we consume and production is based on clonal reproduction (Photo: S. Podhuvan). Flowers are showy and small, but their pollinators are not well known (Photo: Ogniw).

Ginger

The part of the plant we consume from ginger is its rhizome, meaning that one can plant the piece of ginger one buys in the store and one would grow a ginger plant! This plant species also originated from the Southeast Asian archipelago. The plant is easy to grow, and thrives in warm climates, but most of the world production is currently from India. Under production conditions, ginger is multiplied through the planting of rhizomes, meaning that most of the production is not based on seeds. For this reason, the pollination of this species was not of high production interest until only recently. Indeed, while ginger propagation is based on rhizomes, this does not allow for the use of sexual reproduction for the development of better new varieties that may be resistant to diseases or pests. Recent studies indicated that ginger is extremely hard to pollinate because pollen has a low rate of successful pollination, leading to very low seed success. Several researchers are now focusing on identifying its pollinators, so stay tuned to know more!

cloves
Cloves are the dried immature flowers of the Clove tree. Flowers are harvested right before they open and are dried to reach the product we find in our markets (Photos: Midori, A. Heijne, Peripitus).

Cloves

As with most other spice plants treated here, cloves also come from a tree, which originates from the Moluccas, in Indonesia. While the plant originates in those islands, most of clove production is currently from Indonesia and Madagascar. The part of the plant consumed is the flower buds, which are harvested and then dried to produce the spice we buy. Although we consume the flowers, these plants still require seed production to reproduce, and this is central to maintaining clove production. Because the plant can self-pollinate but its genetics are improved by cross-pollination, pollinators are very important for its reproduction. Here, again, pollination is not very well known, but flies, bees, and some butterflies are suspected to play an important role in transferring pollen, as it has been observed in a closely related (but not cultivated) species.

Note: this blog post is dedicated with love to Luke Harmon, who despises Pumpkin Spice. <3

By Anahí Espíndola, Assistant Professor, Department of Entomology, University of Maryland, College Park. See more posts by Anahí.