Superorganismality is a major evolutionary transition following the principles of social evolution, which occurred in the wake of previous transitions from simple replicating molecules to eukaryotic, multicellular, sexually-reproducing organisms.

To understand the ultimate causes of this transition, and the proximate mechanisms that underly it, we study the ant Cardiocondyla obscurior, a species well-suited for laboratory research because of its small body and colony size and short lifespan. CoRe is dedicated to a holistic perspective and is highly interdisciplinary.

Developmental plasticity

The ability of one genome to produce alternative phenotypes lies at the root of superorganismal insects. C. obscurior has queens and sterile workers, as well as winged and wingless males. Female castes and male morphs have different determination mechanisms (maternal vs environmental) and decision time points (embryonic vs larval), allowing the simultaneous study of developmental conversion and phenotypic modulation at the extreme end of ant polyphenism.


Social insect queens live exceptionally long compared to solitary insects. In C. obscurior, late-life fitness gains in the form of increased production of queen compared to worker offspring explain the observed delay of the selection shadow and decreasing mortality rates with age. Furthermore, lifespans of both queens and workers are adaptive, as indicated by similar standardized mortality rates. The relatively short lifespan of C. obscurior queens (~6 months) makes it a perfect model to study the biology of aging.


In the context of major evolutionary transitions following the principles of social evolution, C. obscurior also allows the study of maintenance of higher-level associations. C. obscurior harbours intracellular the bacterial endosymbiont Cand. Westeberhardia cardiocondylae (weObs). At the genomic level, Cardiocondyla carries a horizontally transferred gene, presumably from the ancestral weObs, which is thought to allow for more efficient synthesis of purine nucleoside monophosphates compared to de novo synthesis.


There is a growing need to understand how species respond to changing environmental conditions. C. obscurior is a world-wide distributed tramp species that nests in trees and shrubs, with colonies directly exposed to the environment, including to anthropogenic stressors such pesticides. The genome shows a clustered distribution of transposable elements, which may facilitate local adaptation. Populations collected from localities around the world differ in their resistance to pollutant and temperature stress, an effect that may also be linked to differences in their endosymbiont communities.

Social dynamics

Superorganismality is characterised by synergistic effects arising from cooperation between independently operating units. Investigating how these processes optimize the environment of the superorganism is essential for understanding the ecological and evolutionary success of social insects. The small size of Cardiocondyla colonies allows the study of these optimization processes at a fine scale in ecologically-relevant contexts, from the organisation of foraging, to brood care, hygienic behavior, and nest defense.