Wasp Societies Tackle Fierce Leadership Battles

When the loss of a queen wasp triggers a power struggle and social turmoil, colonies can survive the upheaval thanks to helpful wasps that pick up the slack, finds a new study led by UCL researchers.

The findings, published in the journal Animal Behaviour, show that even in colonies where leadership succession is violent and chaotic, there are individual wasps that compensate for the upheaval by working harder on essential tasks.

The study focuses on cooperative societies of tropical paper wasps (Polistes canadensis), found in the Caribbean, where many individuals live together but reproduction is controlled by a single dominant female. But the other female workers are not sterile, and could take over as the next breeder if a power vacuum arises.

To understand how colonies respond to leadership loss, UCL researchers experimentally removed queens from established colonies. What followed was immediate disruption.

Aggressive interactions between females escalated as multiple wasps competed for reproductive dominance, and the colony's usual social networks rapidly broke down. Rather than a smooth transfer of power, succession involved a period of intense conflict involving many group members.

Despite this turmoil, the wasp colonies did not collapse. Instead, stability was maintained by a distinct group of individuals the researchers term "compensators." These compensators avoided engaging in aggressive conflict and power struggles, and instead increased their investment in essential tasks such as foraging and brood care. By ensuring that food continued to reach developing offspring, they helped maintain societal function through periods of intense social turmoil.

The compensators did not appear to be biologically different from those engaging in fighting, which the researchers say suggests their behaviour may reflect strategic decisions rather than fixed roles. Some wasps may see achieving dominance as their best chance of future reproduction, while others seek to ensure the survival of the brood, typically composed of the workers' own siblings.

Lead author Dr Owen Corbett (UCL Centre for Biodiversity & Environment Research, UCL Biosciences), who conducted this study as part of his PhD at UCL, said: "The conflict after queen removal was intense, but it wasn't the whole story.

"While some individuals fought over dominance, others completely avoided the conflict and quietly stepped up to keep the colony running. Cooperation didn't disappear; it was redistributed."

The research provides a rare window into a poorly studied form of reproductive succession in tropical cooperative wasps. Most previous studies of cooperative colonies have focused on temperate species such as those found in Europe or North America that have highly ordered dominance hierarchies and predictable succession rules. This study instead examined a more chaotic, aggression-driven system in a group that has received far less attention, broadening understanding of the diverse ways animal societies can resolve leadership conflicts.

These insights come from a fresh analysis of behavioural data collected by some of this study's research team during fieldwork in the early 2000s in Panama.

The findings challenge the idea that cooperative societies must depend on orderly, rule-based succession systems to remain stable. While aggression-based succession is often assumed to be too costly to persist, the study shows that such systems can be viable when compensators offset the costs of conflict.

Senior author Professor Seirian Sumner (UCL Centre for Biodiversity & Environment Research, UCL Biosciences) said: "Understanding how animal societies manage conflict can help us think differently about cooperation more broadly. In times of turmoil, society depends on those who keep doing the essential work in the background. In many ways, we may be more like wasps than we realise."

The research was funded by the Natural Environment Research Council (NERC) and the Smithsonian Institution.