Ant Supergene Uncovers New Twists and Secrets Behind Social Behavior Evolution

Researchers at the University of Oulu in Finland have illuminated a dynamic aspect of insect social evolution. Their investigations into ant colonies revealed that the presence of multiple queens does not rely solely on stable genetic anchors. Two studies published in Molecular Biology and Evolution demonstrated how these societies adapt when key genetic elements shift or disappear entirely.[1]

A New Supergene Shapes Queen Dynamics

Scientists turned their attention to Myrmica ruginodis, a furrowed ant species common in Eurasian forests. These ants nest under mossy ground cover. Some colonies featured a solitary queen that produced large daughters ready to disperse and start new nests. Others hosted multiple queens generating smaller offspring that stayed and reproduced locally.

The team identified a previously unknown supergene as the driver behind these differences. This large genomic block, encompassing hundreds of genes inherited as a unit, controlled both queen size and colony structure. Lead author Hanna Sigeman noted the pattern’s recurrence across species. “It’s interesting how evolution keeps finding similar genetic solutions in ants,” she said. “Supergenes have independently evolved in different species to control similar social traits, and each new example helps us narrow down which genes are important for shaping ant societies.”[1]

Wood Ants Lose a Genetic Anchor Yet Persist

Formica wood ants presented an even greater surprise. These insects construct prominent mounds in forests and link nests into expansive supercolonies via trail networks. Earlier work had tied multiple-queen setups to an ancient supergene. However, in two species, that supergene had vanished completely from the genome.

Despite this loss, colonies still supported hundreds of reproducing queens. Investigators discovered two genes once housed in the supergene had migrated to new genomic locations. University Lecturer Lumi Viljakainen, who headed the group, expressed initial confusion. “We were puzzled by how multiple queens could still coexist when the supergene thought to enable this had been lost,” she recalled. These relocated genes likely sustained queen tolerance within nests.[1]

Understanding Supergenes in Social Evolution

Supergenes act as robust units that suppress recombination, keeping linked genes together across generations. In ants, they frequently govern social organization, from queen numbers to worker roles. The Finnish studies highlighted their rise and fall. Evolution crafted these complexes for advantages like efficient multi-queen cooperation.

Over time, however, burdens emerged. Viljakainen explained that once-beneficial setups could accumulate harmful mutations, prompting their dismantlement. Genes might then scatter or reposition to preserve function. This adaptability underscores evolution’s opportunistic nature.

• Supergenes evolve independently in various ant lineages to regulate queen traits.
• Loss of a supergene does not erase the associated social behavior.
• Individual genes can relocate and sustain colony harmony.
• Ants serve as prime models for genetic drivers of cooperation.
• Evolutionary paths diverge, yielding parallel solutions to social challenges.

Implications for Broader Evolutionary Insights

The findings challenge rigid views of genetic determinism in social insects. Complex behaviors like polygyny – multiple queens per colony – prove resilient to genomic upheaval. Researchers linked this to ants’ role as evolutionary laboratories. Their eusocial systems offer windows into cooperation’s origins.

Future work may pinpoint exact gene functions. The studies, detailed in one paper on Myrmica ruginodis and another on Formica, emphasize non-linear trajectories. Viljakainen added, “Our results also show that complex social traits can persist even when their genetic basis changes. Evolution is not a single linear path – it often finds multiple solutions to the same problem.”[1]

These discoveries reveal nature’s ingenuity in sustaining ant societies amid genetic flux. They invite further exploration into how cooperation endures evolutionary pressures. What aspects of ant sociality intrigue you most? Share your thoughts in the comments.