Toolbox update 6: Methods for studying pollen

Team Pteropus would like to share a few helpful tips and protocols on how to collect and study pollen. This isn’t just useful for budding botanists, plant ecologists or beekepers! It’s also relevant for wildlife ecologists who want to study the diet of animals that feed on flowers. It’s a good way to identify plant species in animal diet, as different types of plants have different, distinctive pollen shapes and sizes. In order to do this, you’ll need to start by collecting pollen samples directly from the flowers themselves, to build up your very own pollen reference library.

The pollen grains of the passion flower (Passiflora sp.) have a very distinctive 'tennis ball' shape
The pollen grains of the passion flower (Passiflora sp.) have a very distinctive ‘tennis ball’ shape

This latest Biologist’s Toolbox post comes to you all the way from San Jose courtesy of Esteban, who shares with us the pollen extraction protocol he was trained to use by his university. Although it’s also possible (and preferable) to use a Scanning Electron Microscope (SEM) for pollen studies, this can be complicated and expensive. This protocol provides you with a simple and easy-to-adapt method to be used with a normal light microscope, and which you can easily execute yourself.

According to Esteban:

“Studying pollination and pollen predation without a proper reference collection is an impossible thing to do! Some of the pollen is trapped in the animals’ faeces, and can’t be identified without a proper extraction method. Here we present a protocol for pollen extraction from fresh flowers and faecal samples. This can be used to create a reference collection, and kept for a long time.

This method was originally used to extract pollen from honey samples (Sawyer 1981). It was modified by biology students from the University of Costa Rica, and used for pollen extraction from bird faeces in a couple of our field courses in the Cerro de la Muerte Highlands, Costa Rica, with good results. One of the highlights of extracting pollen like this is the pureness of the final sample, which is separated from other organic components that might interfere with the proper pollen identification. So what I like about this method is that the final result is a really clean pollen sampler. Another benefit is the long-term preservation of the samples.”

Sawyer, R 1981. Pollen Identification for beekeepers. UC Press.

In addition to the pollen extraction protocol, we’ve also included some helpful instructions on how to make your own fuchsin stain jelly. This was adapted from a recipe in Beattie (1971), which we managed to successfully reproduce for Project Pteropus. We’ve added in some tips based on our experience.

Beattie, AJ 1971. Technique for study of insect-borne pollen. The Pan-Pacific Entomologist 47(1): 82.

Download the protocols!

Studying pollen grains under a light microscope
Studying pollen grains under a light microscope
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