Is it possible to put a price on nature?

An ecosystem service is a concept that quantifies nature in economic terms. The Millennium Ecosystem Assessment defines it as the benefits people derive from ecosystems. In essence, how nature makes our existence both enjoyable and possible.

Some of these services are very simple, such as providing goods or provisions; others are linked to recreational enjoyment and even our spirituality. However, the most important are regulating services. These are core processes, like the purification of air and water, which allow for our survival.

Pollination is included in this class of services. In a 2020 scientific paper, biologist Rafaella Porto and her collaborators estimated that crop pollination services ranged from $195 billion to $387 billion annually. It is clear that this product is of high value and strengthens conservation arguments for the myriad insects that carry out this task.

While pollination — the transfer of male sex cells in plants (gametes) to female reproductive structures — is vital, insects did not always facilitate it.

Before we continue to look at the evolution of pollination, it is important to note why sexual reproduction is important for plants. After all, many lineages of plants can proliferate without pollination.

In a study of evening primrose (Oenothera), asexual species accumulated more adverse DNA mutations compared to their sexual counterparts. Also, sexual species gain genetic variability faster, which can provide resistance to pests and adaptations, allowing them to thrive better in their habitat.

Prior to animal pollinators, water facilitated the transfer of gametes. Modern species from ancient lineages, such as Bryophytes (liverworts, hornworts and mosses) and Pteridophytes (ferns), all require a thin film of water to transfer gametes.

As plants evolved, so did their means of pollination. In gymnosperm plants, which include conifers, cycads and ginkgo, there was a switch from water to wind as the pollinator. Members of this group lack flowers because there was no need to attract a pollinator.

This changed with angiosperms, which produce flowers and fruits. All the components of a flower — from the anthers (pollen producers) to the petals — are derived from leaf tissue. The ancient angiosperm lineage emerged during the Lower Cretaceous period, about 130 million to 125 million years ago. This is about the same time we see many insect groups diversify greatly in the fossil record.

The relationship between these two groups is often touted as the premier example of co-evolution — how closely related species influence each other’s evolution.

Early insect pollinators were beetles. Attracted by scent, these are only interested in pollen, as it is high in protein. Flowers that are beetle-pollinated have strong smells that range from sweet to musky or even bleach-like. Magnolias are an example of beetle-pollinated flowers.

Once bees evolved, floral biology switched into overdrive! One example of a unique bee-pollinated plant is the cannonball tree (Courouptia guianensis). The tree lures bees with its strong, pleasant scent and offers a pollen reward. The bee will retrieve sterile pollen, which is readily available on the bottom of the flower. The stamen at the top of the flower is loaded with fertile pollen, which attaches to the bee’s back. You can see bees in action on this tree at the Lyon Arboretum.

Hammer orchids (Drakaea) are unique in the fact that they attract the males of a particular wasp species to be pollinated. The orchids produce pheromones that mimic those released by the females of the species.

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Boost pollination

If you want to encourage pollinators in your area, here are a few tips:

>> Plant native species. Loulu palm tree (Pritchardia), hibiscus and awikiwiki (Canavalia pubescens) are all great options.

>> Increase the diversity of plants in your yard.

>> Do not use pesticides with neonicotinoids — this class of pesticide is deadly to bees.

Jesse Adams is a botanist at the Harold L. Lyon Arboretum, where he works to catalogue, propagate and conserve the plant diversity found there.