One of the luxuries of writing about science is that it gives me a chance to weave together discoveries made in disparate fields. I can connect the stories for readers. Sometimes I can even connect the scientists themselves. But the more I write, the more that I see that where such connections are most conspicuously missed is not random. In some subfields of science our ignorance is both vast and predictable. One of these subfields is the intersection between basic ecology and evolutionary biology and application.
I was thinking about this recently when sitting down to talk to a friend about what science should be. It is a side point, but we don’t ask this question enough. How does science work, as opposed to how should it work? Most of the daily things we do in science we do not because they are the perfect approach to science but instead because it is the way they have been done. This includes how we train graduate students and which questions graduate students choose to focus on for projects. It was a long night. We disagreed at the end, but had fun talking. I don’t propose to resolve all the answers here, but I will offer one perspective, namely that most graduate student projects are boring and they don’t need to be.
I just finished a book on the value of basic ecology and evolutionary biology to agriculture. In doing so, I bumped up against several big holes in our understanding. If you are a graduate student looking for something to work on, jump into one of these holes. Each will prove, I suspect, deeper than thought and more interesting.
1) Grain Beetles
Grain beetles are flightless and rely upon specialized microbes in order to obtain the nutrients they need to live off of grain (this should be a lesson for us). Yet, we know almost nothing about how these beetles evolved flightless-ness, nor when, and from where, they picked up their symbionts. Both of these questions are very answerable with modern methods and if answered well could become a classic example of the rapid evolution of a pest in response to a novel food.
Domesticated cacao (chocolate) is pollinated by flies, but it has long been suggested that the flies are not the original pollinator of the cacao. In the Amazon, pollen has been shown to travel as far as three kilometers among cacao trees (far too far to be due to the flies). What pollinates wild cacao? This is knowable and if anyone is interested in partnering with us, we’d be glad to help Amazonian schools in Colombia or Ecuador study this question.
3) Global yield of crops
Much of the global yield of crops depends on the absence of pests and pathogens from the native ranges of those same crops. We don’t have a measurement of how much this yield reprieve contributes to agriculture today, nor do we understand which crops in which regions are experiencing them. Nor do we have predictions of how these regions are likely to change with climate change. All of these questions can be answered, they just haven’t been.
Cassava, also known as manioc or yucca, has seeds with tiny fruits that evolved to attract ants. Ants carry the seeds away, feed the fruits to their babies, and throw the seeds in their garbage piles. Or, at least that is what we think happens. Although thousands of studies have been done on the dispersal of seeds by ants, essentially no work (one study) has been done on the only plant dispersed by ants that is a major food crop. Here is the epitome of how the divide between application and basic research hurts us. The basic biologists assume that someone in crop science is studying cacao seeds. The folks in crop science figure that there is an ant biologist out there somewhere doing the work. No one is. Because cassava now tends to be planted using stems, the seeds have relatively little bearing on the way we farm cassava, but they have a strong influence on how we understand its evolution and even such simple question as why cassava evolved to be poisonous in the first place.
Potatoes are a pretty wonderful crop. They produce plenty and do so in a way that yields a lot of food for relatively little land. Like cassava, potatoes are primarily reproduced vegetatively (little hunks of potato are used to make new potato plants). But the original diversity of potatoes is all due to sexual reproduction of potato plants, wherein some insect pollinates a potato flower and, in doing so, mixes the genes of one plant with those of another. This sex was necessary in order to generate the vast diversity of potato varieties that exist in the Andes and every indication is that sex continues to play a role in the development of new varieties. What is amazing in this light is that we know little about which insects (we assume they are bees) pollinate potatoes in their native range. They could be endangered right now and we wouldn’t have a clue. Go study them.
6) Natural enemies of crop pests
The global sustainability of many crops depends upon the species that attack and kill the pests of our crops, their natural enemies. The diversity of natural enemies of crop pests is not known, nor are the regions in which they are most diverse, nor is whether some of these natural enemies are at risk from habitat loss. Here, the possibilities and questions are many. Where are the hot spots of natural enemies? How do we conserve natural enemies? Could we build up a repository of natural enemies? These questions are all un-answered (and mostly unasked) even for groups of natural enemies we already know to be important. A small wasp, a single species of wasp, saved the cassava of Africa from the cassava mealybug. No one has ever studied the evolution of this wasp, what its closest relatives are, or where such relatives might be.
7) Crop traits which influenced whether or not they were moved
Oh, this one keeps me up at night. Huge numbers of hours have gone in to predicting the attributes of species that allow them to succeed. Massive studies. Australian studies. New Zealand studies. U.S. studies. German studies. You get the idea. We have virtually no understanding of which traits of crop species and crop varieties influenced whether or not they were moved with the conquistadors and later. In as much as we are still farming many crop varieties descended from those first batches of crops (and still ignoring crop varieties the conquistadors ignored), knowing why seems relevant. For example, did they tend to simply be things that looked like European foods, but stored well on half rotten ships?
8) Species that traveled on the ships of conquistadors
Whole books have been written about the Colombian Exchange and the crop and pathogen species that did and did not move with the conquistadors and subsequently, and how they changed history. No attempt has ever been made to reconstruct all of the other species that also traveled on those same ships. If we have learned anything from the study of houses (which share a great deal with ships) it is that those dirty ships are likely to have carried tens of thousands of species rather than just tens.
9) Pest and pathogen hotspots
Are there geographic hotspots from which pests and pathogens of crops tend to emerge?
10) The evolutionary arms race of crop pests and pathogens
We are in an evolutionary race with the pests and pathogens of our crops. The more we intensify agriculture, the faster this race gets. The fewer people control the seeds of our crops, the more the race will depend upon the cleverness of those people. This dependence is tenuous. How do we best slow down the evolutionary arms race? People are working on this one, but we need more. Our food (and with it, our civilization) depends upon it.
Just from Never Out of Season, I have about ninety more of these. I’ll slowly add them here if you want to keep an eye and if I get a chance I’ll add the similarly long lists from my other books. I’ve long known it to be true that most of what is knowable is not yet known. It has taken me longer to realize the more significant assertion, that most of what is knowable and of consequence to civilization’s persistence is not yet known.