Periodic Reporting for period 1 - diseaseINgroups (Disease defence in groups: the role of relatedness, risk and pathogen type)
Okres sprawozdawczy: 2021-10-01 do 2023-09-30
Living in groups provides many benefits, such as protection from predators, easier access to food, and help with offspring care, but it also brings one major risk: infectious disease spreads more easily among social individuals. Animals don’t have doctors or healthcare systems like we do, so how do they protect themselves and their group members from disease? While highly social insects such as ants and bees live in large families and are known to protect their relatives through collective disease defences, it remains unknown how non-eusocial animals coordinate to prevent infections from spreading within their groups.
The diseaseINgroups project set out to answer this question using the red flour beetle (Tribolium castaneum), a small, tractable insect that lives in crowded groups in stored grains. The project’s main objectives were to (1) establish Tribolium as a new model species for studying disease defences in groups, (2) identify the behaviours that limit pathogen transmission, and (3) uncover the underlying chemical and molecular mechanisms that coordinate these behaviours under infection risk.
The project revealed that flour beetles exhibit coordinated behavioural responses—such as grooming and removal of infected individuals—that effectively prevent pathogen transmission within groups. These findings demonstrate that even non-eusocial animals can achieve powerful, group-level protection through collective behaviour, establishing Tribolium as a new model for studying cooperation and disease management beyond family-based systems. Understanding how animals naturally limit disease spread is not only important for evolutionary biology but also for society: it can inspire new approaches to managing infections in agriculture and livestock, improve models of disease transmission, and provide insights into how cooperation and collective action evolve under pathogen pressure.
The diseaseINgroups project set out to answer this question using the red flour beetle (Tribolium castaneum), a small, tractable insect that lives in crowded groups in stored grains. The project’s main objectives were to (1) establish Tribolium as a new model species for studying disease defences in groups, (2) identify the behaviours that limit pathogen transmission, and (3) uncover the underlying chemical and molecular mechanisms that coordinate these behaviours under infection risk.
The project revealed that flour beetles exhibit coordinated behavioural responses—such as grooming and removal of infected individuals—that effectively prevent pathogen transmission within groups. These findings demonstrate that even non-eusocial animals can achieve powerful, group-level protection through collective behaviour, establishing Tribolium as a new model for studying cooperation and disease management beyond family-based systems. Understanding how animals naturally limit disease spread is not only important for evolutionary biology but also for society: it can inspire new approaches to managing infections in agriculture and livestock, improve models of disease transmission, and provide insights into how cooperation and collective action evolve under pathogen pressure.
During the project, extensive behavioural experiments were performed using two insect pathogens—bacterium Bacillus thuringiensis and fungus Metarhizium brunneum. The results revealed that flour beetles display remarkable collective responses to disease. Healthy adults actively groom larvae exposed to pathogens, increasing their survival chances. When infection nevertheless occurs, dead or dying larvae are rapidly cannibalised, preventing the pathogen from spreading further. We discovered that smell plays a key role in triggering these collective defences: beetles can detect the odour of infected larvae or cadavers and react accordingly—either by grooming or removing them. This shows that chemical cues guide group behaviour during disease outbreaks, enabling beetles to recognise and respond to infection before it spreads. Together, these behaviours efficiently eliminate pathogen transmission within groups—demonstrating a powerful form of group-level disease defence previously thought to be restricted to eusocial species such as ants and termites. Nevertheless, we are currently investigating whether these group-level responses represent genuine cooperation that benefits the group as a whole, or whether they can arise from individually selfish strategies that incidentally protect others. Chemical analyses to identify the specific odour compounds that trigger these behaviours are ongoing.
The results have been disseminated through an oral presentation at an international scientific conference and through several public outreach activities (3–4 per year), where the concepts of social immunity and collective disease defence were presented to broad audiences. Our findings position Tribolium as a powerful model for exploring how social behaviour evolves under pathogen pressure, and they have potential applications in pest and pathogen management, as understanding natural group-level immunity can inform more effective biological control strategies.
The results have been disseminated through an oral presentation at an international scientific conference and through several public outreach activities (3–4 per year), where the concepts of social immunity and collective disease defence were presented to broad audiences. Our findings position Tribolium as a powerful model for exploring how social behaviour evolves under pathogen pressure, and they have potential applications in pest and pathogen management, as understanding natural group-level immunity can inform more effective biological control strategies.
By uncovering that non-eusocial insects can achieve complete protection through collective behaviour, diseaseINgroups fundamentally advances our understanding of the evolution of disease management. The discovery positions Tribolium as a new model organism for studying how group living shapes immunity, behaviour, and epidemiological dynamics, and particularly for exploring the evolution of cooperation in the context of disease. Beyond basic science, these results have practical relevance: flour beetles are major agricultural pests, and their collective resistance may influence the success of biological control agents. More broadly, insights from this research can inform epidemiological and evolutionary models used to predict how social behaviour affects pathogen spread in animals.