On January 11th, I returned to Puerto Rico to begin my first full season of field work for my PhD. I’ll be here for 2.5 months, so I’m excited and nervous…need to make sure I get everything done during that time! Why am I in a rush? Because everything I’m doing is dependent on coffee flowers, which bloom during mass floration events. I think it’ll be action-packed, but my new technician (Rafael) seems pretty great, and I think (or hope!) the two of us can get everything done in time 🙂

So, what exactly are we doing? Well this year, I’m going to try and tackle two of my objectives:

1- determine how the heterogeneity of the landscape (coffee plantation + forest) affects bees in sun and shade coffee plantations

2- determine if mother nature (bees, wind, other insects, etc) is doing her job when it comes to pollinating coffee. There are two species of coffee here in PR: Coffea canephora and Coffea arabica. Arabica can produce fruit via wind pollination, but the quality of the coffee can actually improve with animal pollination. Canephora (also called Robusta) is entirely dependent on cross-pollination by animals.

So, how are we going about addressing these objectives?

Well for 1- we plan on setting traps out in the forest fragments found within the farms, and in the coffee plantation (shade or sun). We’ll set the traps out once a month and sample them with a sweep net twice a month and see how the bee population differs over time (before flowering, during flowering, after flowering) in the coffee plantation and in the forest patches.

For 2- we will hand-pollinate some flowers on one branch, and leave another branch on the coffee plant as our control (i.e. mother-nature pollinated). Hand-pollination means that we collect pollen from other coffee plants, and use that pollen to pollinate flowers using a paint brush (See images below!). Then, we count all the flowers on the hand-pollinated branch and all the flowers on the mother-nature pollinated branch, and we’ll return in October-November when it’s time for coffee harvest and compare the quantity and quality of the coffee beans produced on both branches. IF the coffee quality and quantity is the same on both the hand-pollinated branch and all the flowers on the mother-nature pollinated branch, then mother nature is doing her job! If it’s less on the mother-nature branch, then the pollination services are lacking.

Eppendorf tube with the anthers (pollen carrying parts) of coffee plants which we do not hand-pollinate. We don’t want to have the plant self-pollinate…we want a diversity of pollen from other plants.

Coffee flower ready for hand-pollination. If you look closely, you can see the anthers around the outer edges of the flower, and the stigma (part that receives the pollen) in the middle. The stigma looks like a “Y”

Hand-pollinating! We dip the paint brush into the pollen in our eppendorf tube and then touch the stigma. That way we transfer the pollen to the sticky, receptive stigma (right in front of the paint brush)!

It’s tedious work, but thankfully the weather up in the mountains is quite nice and cool, and the views are amazing! So, even though this is work, it doesn’t really feel like it 🙂

Gorgeous view from one of our C. canephora farms in Las Marias, Puerto Rico