Ecology is not a dirty word

The robot bee story is back in the news. I covered some of the new research and associated media hype last year. The latest: a patent has been filed for building ‘pollinator drones’ and the media (both newsy and social) are in despair, as the end is clearly nigh.

But don’t worry. Here are a few challenges the pollinator drones will need to overcome before they can take over agriculture:

• The cost to build and maintain these drones would be unsustainable. And the opportunity cost involved in building these drones vs. adopting sustainable management practices and managing farms to support actual pollinators is ridiculous. Check out this interesting post from Matt Kelly, breaking down some of those costs.
• Pollination is an ecological interaction between plants and a vector, usually animals. There are numerous natural factors that influence crop pollination ‘success’ (the fruit or seed that we eat), most of which cannot be controlled by a robotic drone.
• Goldilocks knew her stuff. Every plant species produces a unique type of flower. Each flower type requires different types of pollinators to visit and behave in different ways on the flower to pollinate it.
• Successful pollination often depends on where the pollinator visited beforehand: pollen from other plant species can reduce pollination success, pollen from other varieties of the same plant species can affect pollination in different ways, and bacteria or fungi that naturally live in the nectar of other flowers can affect reproduction of another flower. Managing these natural interactions is beyond the scope of a drone.
• Many crops require multiple visits by multiple types of pollinators to optimise the chance of the right pollen fertilising the egg (ovule) and producing fruit/seeds.
• The shape and size of a flower affects how successful a pollinator is at putting the right pollen in the right spot. The drones described in the patent might work on open, dish-shaped flowers (e.g. almonds or apples), but probably only on the ones on the tree that are facing upwards. The drones probably won’t work on flowers that a pollinator has to ‘buzz’ or get deep inside to pollinate (e.g. blueberries, most squashes, tomatoes, canola, beans, macadamia, eggplant, etc.). And the crops with dish-shaped flowers still need different varieties growing together to ensure the cross-pollination required to reproduce.
• There are still plenty of things we don’t know about how to optimally pollinate each crop species (so drones don’t know this either): e.g. how long does an insect have to spend on each flower? which insects? what sort of behaviour do they need to have on the flower to pollinate it? how many pollen grains are too many, or not enough? what time of day is best for pollination? what is the ideal temperature & humidity for pollination?

As an aside, this patent would never have been published in a scientific journal. The brief ‘background’, which attempts to justify the need for these drones, is unreferenced and contains basic errors. It first claims that “the amount” of pollinators (including ants, which rarely pollinate and can leave chemicals on flowers that have negative effects on plant reproduction) are in decline. According to the patent, pollinator declines lead to reduced crop biodiversity…in fact, it generally works the other way around.

The remaining text presents a very weak argument; we need drones because crop pollen-dusting via airplanes is expensive and ineffective… True. And this is probably why pollen-dusting rarely happens. I’ve never heard of this happening at all, although I’m sure someone has tried it!

Finally, throughout the entire patent, the authors talk about the drones collecting pollen from one ‘crop’ and moving to another ‘crop’ to create pollination magic. This is impossible. If you put pollen from the flower of one crop (e.g. almond) onto the flower of another crop (e.g. tomato), nothing will happen. They are incompatible.

These pollination drones will be fun toys, and they could also be useful educational tools. They might even be destined for a life on Mars. But, no fear, they wouldn’t last long on most farms on Earth.

© Manu Saunders 2018