Scientists find new colony structure of fire ants evolved in one species before spreading to others

Date:
March 11, 2022
Source:
Queen Mary University of London
Summary:
Scientists have discovered that a new form of ant society
spread across species. They found that after the new form of
society evolved in one species, a 'social supergene' carrying
the instruction-set for the new social form spread into other
species. This spread occurred through hybridization, i.e., breeding
between ants of different species. This unlikely event provides
an alternate way of life, making the ants more successful than if
they only had the original social form.



FULL STORY ========================================================================== Scientists from Queen Mary University of London have discovered that a
new form of ant society spread across species. They found that after
the new form of society evolved in one species, a "social supergene"
carrying the instruction- set for the new social form spread into other species. This spread occurred through hybridisation, i.e., breeding
between ants of different species. This unlikely event provides an
alternate way of life, making the ants more successful than if they only
had the original social form.


==========================================================================
Red fire ants originally had only colonies with one queen. The team
previously discovered that about one million years ago, a new social form evolved where colonies could have dozens of queens. A particular version
of a large section of chromosome, named the "social supergene," includes
the genetic information necessary to make workers accept more than
one queen. The new research, published today in Nature Communications,
analysed the entire genomes or instruction sets of 365 male fire ants
to examine the evolution of the social supergene, and found that the
same version of this chromosome is present in multiple fire ant species.

Transfer of large amounts of genetic information across species is
rare because of genetic incompatibilities. However, in this case, the advantages of having multiple queens overrode the incompatibilities,
and the genetic material repeatedly spread to other species from
the one source species in which this new social form evolved. The multiple-queen social form has advantages in several situations. For
example, a multiple-queen colony has more workers and thus can outcompete
a colony with only one queen. Furthermore, if there is a flood, a colony
with multiple queens is less likely to become queenless.

Dr Yannick Wurm, Reader in Evolutionary Genomics and Bioinformatics at
Queen Mary University of London and a fellow of The Alan Turing Institute
said: "This research reveals how evolutionary innovations can spread
across species. It also shows how evolution works at the level of DNA
and chromosomes.

"It was incredibly surprising to discover that other species could acquire
a new form of social organisation through hybridisation. The supergene
region that creates multi-queen colonies is a large piece of chromosome
that contains hundreds of genes. The many parts of a genome evolve to work together in fine- tuned manners, thus suddenly having a mix with different versions of many genes from another species is complicated and quite rare.

"Instead of executing extra queens as they would in a single-queen
colony, the new version of the supergene leads workers to accept
multiple queens. Having studied the history of the supergene and new
social form extensively, we next want to identify which genes or parts
of the supergene region, lead to these changes in behaviour. This will
also help fill more gaps in our understanding of evolutionary processes." Rodrigo Pracana, a lead author of the study, also at Queen Mary University
of London added: "Our study shows how detailed analysis of large numbers
of wild animals can provide surprising new insight on how evolution
works." The team from Queen Mary were previously among the first in the
world to apply large-scale DNA-sequencing approaches to wild insects --
which enabled them to discover one of the first well-known supergenes.

Red fire ants are native to South America and infamous for their painful
sting.

One of these species is known in many other parts of the world, where it
is aggressiveness and high population density have made it an invasive
pest.

Efforts at controlling the spread of this species have largely been unsuccessful, as indicated by its Latin name, Solenopsis invicta, meaning
"the invincible." The research was supported by the Leibniz Institute
for the Analysis of Biodiversity Change, with Dr. Eckart Stolle assisting
as part of the team at Queen Mary before continuing this work at the
Leibniz Institute.


========================================================================== Story Source: Materials provided by Queen_Mary_University_of_London. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Eckart Stolle, Rodrigo Pracana, Federico Lo'pez-Osorio, Marian
K. Priebe,
Gabriel Luis Herna'ndez, Claudia Castillo-Carrillo, Maria Cristina
Arias, Carolina Ivon Paris, Martin Bollazzi, Anurag Priyam,
Yannick Wurm.

Recurring adaptive introgression of a supergene variant that
determines social organization. Nature Communications, 2022; 13
(1) DOI: 10.1038/ s41467-022-28806-7 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/03/220311095304.htm

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