Thread by @FoodWebEcoEvo

New paper in @ScienceMagazine with @SpicyBotrytis and Jordi Bascompte. We show that a single allele at a single gene can control the coexistence of species in a food web. @UZH_Science @UCDavisPlants @uzh_gcb science.org/doi/10.1126/sc… Thread 👇1/9

Over 50 years ago, Bob Paine discovered that starfish act as a keystone species in that their presence in the rocky intertidal food web maintains the coexistence of diverse species. 2/9

Just as certain species can have large ecological effects, so too might certain genes. We experimentally tested the effect of three plant defense genes on the persistence of an insect food web in the lab. 3/9

Every week for four months, we counted the abundance of each insect species and replaced plants to monitor the effect of specific genes on food-web dynamics. 4/9

What we found next surprised us. Analogous to a keystone species that maintains species diversity in a food web, we found that the plant's AOP2 gene acts as a “keystone gene” through its disproportionate contribution to maintaining species diversity. 5/9

But how exactly was AOP2 maintaining species diversity? We then tested AOP2’s effect on food-web transitions, and found that plants with a null AOP2- allele maintained species diversity by preventing the complete collapse of the plant-aphid-parasitoid food chain. 6/9

So now we know AOP2 prevents the food chain from collapsing, but we still didn’t know the mechanism. To get at this, we combined our empirical community time series data with theory on the structural stability of food webs. 7/9

We found that plants with a null AOP2- allele fostered coexistence by increasing the aphid’s and parasitoid’s population growth rate at low density. This bottom-up effect is likely due to a pleiotropic effect of AOP2 on plant growth rate. 8/9

Our work highlights the promise of integrating tools from #genetics and #foodwebs to predict the consequences of #biodiversity change across scales, and warns that losing genetic diversity may cause abrupt and catastrophic shifts in food-web structure and function. 9/9

@threadreaderapp unroll