Why did it take so long to do the genome analysis? It turns out that the easiest part of the study may have been the comparative genome analysis. Finding the ants in the first place proved to be the greatest major hurdle. Why?
Populations of ant social parasites are almost invariably small and patchily distributed. How patchy?
Well, the last time that one of the species, P. argentina was seen in the wild was 1924, a time well before the discovery of DNA as the hereditary chemical unit of life.
Rabeling remembers prior trips to South America that were in vain because they could not find P. argentina. Then, about a decade ago, a phone call from colleague Martin Bollazzi and study co-author changed his life.
“Martin Bollazzi said his wife Leticia just re-discovered P. argentina!!!”
Rabeling hopped on a plane as fast as he could. When he saw P. argentina up close, it was a moment of discovery he’ll never forget.
“Leticia’s rediscovery of P. argentina was the find of a lifetime. What I especially love is to connect the ant field work and natural history observations with the new technologies like whole genome sequencing, and to have the opportunity to do so was such a joy.”
Now, they could make their research dreams a reality by collecting P. argentina and put their field work-based hypotheses to the test by doing the first modern whole genome sequencing of social parasitic ants.
Their results are not only important to understanding ants, but offer insights into the role of these genomic ‘loss-of-function’ study systems in other parasites and for identifying hallmarks of cooperative social colony life at both the phenotypic and the genomic levels.
“Social parasites came to exploit the foraging efforts, nursing behavior and colony infrastructure of their hosts,” said Rabeling.
Rabeling also points to other species, such as the Mexican blind cave-dwelling fish or other parasites such as tapeworms as examples of organisms that lost important traits over time. In each case, they have developed and exploited novel ecological niches. for their species survival.
From these first 3 social parasite ant species, they have learned a lot. Next, they plan on future genomics studies of these ant social parasites to generate exciting further insights, particularly with long-read sequencing technologies allowing analyses in even greater detail.
But Rabeling and his colleagues are now involved in another race against time — as every year, more and more natural ant habitats are lost to deforestation and development. Now, our understanding of ant evolution depends on people to cooperate to save biodiversity — while we still can.
“We hope such future studies can expand our knowledge on the signatures of the evolution of social behavior in ants, for which few other model systems can offer such species-level sample sizes of several dozens.”