TY - JOUR

T1 - Relaxed selection underlies genome erosion in socially parasitic ant species

AU - Schrader, Lukas

AU - Pan, Hailin

AU - Bollazzi, Martin

AU - Schiøtt, Morten

AU - Larabee, Fredrick J.

AU - Bi, Xupeng

AU - Deng, Yuan

AU - Zhang, Guojie

AU - Boomsma, Jacobus J.

AU - Rabeling, Christian

N1 - Funding Information: This study was supported by grants from the European Research Council (ERC Advanced grant 323085) (J.J.B.), the US National Science Foundation (DEB-1654829 and CAREER DEB-1943626), the University of Rochester, and Arizona State University (C.R.), as well as the Lundbeck Foundation (R190-2014-2827) (G.Z.). The Visitor’s Office of the Smithsonian Tropical Research Institute provided logistic help and facilities to work in Gamboa and the Autoridad Nacional del Ambiente y el Mar (ANAM) gave permission to sample and export ants from Panama. We gratefully acknowledge the Dirección General de Recursos Naturales Renovables for permission to conduct field research in Uruguay, and Daniel Ramírez from Cambium Forestal for facilitating access to our Uruguayan field research sites. M.B. thanks Leticia Tejera for her discovery of the P. argentina population. Publisher Copyright: © 2021, The Author(s).

PY - 2021

Y1 - 2021

N2 - Inquiline ants are highly specialized and obligate social parasites that infiltrate and exploit colonies of closely related species. They have evolved many times convergently, are often evolutionarily young lineages, and are almost invariably rare. Focusing on the leaf-cutting ant genus Acromyrmex, we compared genomes of three inquiline social parasites with their free-living, closely-related hosts. The social parasite genomes show distinct signatures of erosion compared to the host lineages, as a consequence of relaxed selective constraints on traits associated with cooperative ant colony life and of inquilines having very small effective population sizes. We find parallel gene losses, particularly in olfactory receptors, consistent with inquiline species having highly reduced social behavioral repertoires. Many of the genomic changes that we uncover resemble those observed in the genomes of obligate non-social parasites and intracellular endosymbionts that branched off into highly specialized, host-dependent niches.

AB - Inquiline ants are highly specialized and obligate social parasites that infiltrate and exploit colonies of closely related species. They have evolved many times convergently, are often evolutionarily young lineages, and are almost invariably rare. Focusing on the leaf-cutting ant genus Acromyrmex, we compared genomes of three inquiline social parasites with their free-living, closely-related hosts. The social parasite genomes show distinct signatures of erosion compared to the host lineages, as a consequence of relaxed selective constraints on traits associated with cooperative ant colony life and of inquilines having very small effective population sizes. We find parallel gene losses, particularly in olfactory receptors, consistent with inquiline species having highly reduced social behavioral repertoires. Many of the genomic changes that we uncover resemble those observed in the genomes of obligate non-social parasites and intracellular endosymbionts that branched off into highly specialized, host-dependent niches.

U2 - 10.1038/s41467-021-23178-w

DO - 10.1038/s41467-021-23178-w

M3 - Journal article

C2 - 34006882

AN - SCOPUS:85106049979

VL - 12

JO - Nature Communications

JF - Nature Communications

SN - 2041-1723

M1 - 2918

ER -