Nectar, pollen, measure, nectar, pollen, measure…

**This is going to be a picture heavy post – after all a picture is worth a thousand words! Hope you enjoy!**

So many flowers, so much data! I really can’t complain, though, since things have been going so smoothly. 🙂

We’ve been really lucky with our timing these past two weeks. We’ve been able to arrive to farms either the day of or the day before the coffee flowers opened, which means we were able to either measure floral traits, or bag the flowers to then collect nectar and pollen the following day.

Recall from last week, these are the things we’re measuring. It’s been tricky finding the best way to collect nectar and pollen, but as you’ll see in the photos below, we’ve been able to do it!

  1. floral shape measurements (including size, number of petals, stigma height)
  2. nectar standing crop – the amount of nectar available in the flower when it first opens
    – We collect the nectar from freshly open flowers (which we covered with organza fabric to exclude pollinators).


    We’ve found that pulling the flower off of the branch, while leaving the stigma attached to the branch, is the best way to collect nectar. Coffea canephora (pictured here) has a lot more nectar than Coffea arabica. can see the glistening ball of nectar at the base of the corolla tube. Photo credit: Rafael Chaparro


    Here you can see me using a microcapillary tube to ‘suck’ up the nectar. The tubes are a certain volume (in this case 15 micro-liters). Knowing how long the microcapillary tube is, and how long the nectar amount is within tube, we can calculate the volume of nectar within the flower. Photo credit: Rafael Chaparro

  3. nectar sugar concentration – measured in Brix, we can tell how sweet the nectar is.
  4. nectar caffeine content – caffeine isn’t just something for us humans. Caffeine was actually found to affect bees’ memory, increasing their loyalty to flowers with caffeine (i.e. once they drink the caffeinated nectar, they may be more likely to go to coffee flowers than other flowers with no caffeine)
    – For this step, we just collect between 20-30 micro-liters in a 1.5mL microcentrifuge tube. We’ll send these tube to an expert for caffeine content analysis.
  5. pollen standing crop – how much pollen is on the flower when it first open
    – Here, we have to collect anthers. Thankfully we’ve had a lot of practice doing this last year, so it’s not too difficult at all. We collect the anthers from freshly open flowers (which we covered with organza fabric to exclude pollinators).


    Here you can clearly see the fluffy pollen on the freshly open flowers. The tricky part is keeping the bees off of them, while we pick the anthers off! These are C. canephora flowers Photo credit: Rafael Chaparro


    Here I am picking the anthers off. We have to try not to shake the tree, because the pollen is so loose that it just flies off with any vibration. These are C. canephora flowers. Photo credit: Rafael Chaparro

  6. pollen protein content – pollen is nutritious for bees, so they may opt to go back to flowers that are more nutritious.
    – this step has by far been the trickiest. We use an electric toothbrush to vibrate 5-10mg of pollen off of the anthers into a mircrocentrifuge tube. Unlike the Coffea canephora flowers, the C. arabica flowers are not nearly as pollen filled, so we’ve had issues trying to get the right amount of pollen.


    Here you can see me using a Hello kitty electric toothbrush to vibrate the pollen off of the flower’s anthers. I hold the flower over the microcentrifuge tube, with the anthers place inside. Patience is key! Photo credit: Rafael Chaparro

We’ve spent an entire 8 hour day collecting all the measurements, nectar and pollen from two farms – it’s just Rafael and I for the next two weeks until my two other tech come back. So, we’re busy busy! That being said, as long as things continue this way (slow and steady flowering), I think we can manage. Keep your fingers crossed that the flowers don’t all open at once, next week!

About saraguitiprado

I'm a Tropical Ecologist, Researcher, and Mother
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