Biology subjects

Stroeymeyt, N.

Publications and source records attributed to Stroeymeyt, N..

3 recordsLinked to original sources

bioRxiv2025

A Controlled Test of Risk-Dependent Immune Investment in a Clonal Ant

Biological systems can benefit from distributing defensive investment unevenly, concentrating protection in parts of the system that face higher risk or hold greater strategic value. In social groups, individuals often face asymmetric infection risks based on their behavioural roles, raising the possibility that immune defences are plastically adjusted according to risk. In social insects, this idea has led to the hypothesis that individuals performing high-risk tasks, such as foraging, should invest more in constitutive immune defences to reduce transmission within the colony. However, testing this hypothesis has been hindered by confounding effects of genotype, age, and infection history. We use the clonal raider ant Ooceraea biroi to overcome these limitations. In this system, spontaneous behavioural specialisation between genetically identical, age-matched individuals creates variation in infection risk, while controlling for other sources of variation. We first annotated the O. biroi immune gene repertoire and sequenced the transcriptomes of 77 individuals that showed considerable behavioural variation. We then combined fine-scale individual behavioural tracking with three complementary measures of immune investment: immune-related gene expression, antibacterial activity, and survival following infection. Despite behavioural specialisation, we find no evidence that individuals engaging in higher-risk behaviours invest more in constitutive immune defences. These results contradict a long-standing hypothesis in the field and suggest limits to plastic immune allocation based on infection risk in social insect colonies.

ecology↗

bioRxiv2024

Architectural immunity: ants alter their nest networks to prevent epidemics

In animal groups, spatial heterogeneities shape social contact networks, thereby influencing the transmission of infectious diseases. Active modifications to the spatial environment could thus be a potent tool to mitigate epidemic risk. We tested whether Lasius niger ants modify their nest architecture in response to pathogens by introducing controlor pathogen-treated individuals into nest-digging groups, and monitoring three-dimensional nest morphogenesis over time. Pathogen exposure led to an array of architectural changes including faster nest growth, increased spacing between entrances, transmission-inhibitory changes in overall nest network topology, and reduced chamber centrality. Simulations confirmed that these changes reduced disease spread. These results provide evidence for architectural immunity in a social animal and offer insights into how spatial organisation can be leveraged to decrease epidemic susceptibility.

animal behavior and cognition↗

bioRxiv2023

Synergistic effects of the insecticide flupyradifurone and the entomopathogen Metarhizium brunneum in ants

The global insect decline is largely driven by agricultural pesticides, whose detrimental effects are further amplified by synergistic interactions with other stressors. Whilst there is increasing evidence of adverse impacts of the next-generation insecticide flupyradifurone (FPF), initially marketed as safe for pollinators, its effects on non-pollinators and potential interactions with other stressors remain poorly understood. Here we investigate the impacts of chronic exposure to FPF alone and in combination with the entomopathogenic fungus Metarhizium brunneum in a non-target arthropod: the ant Lasius niger. Our results show that FPF concentrations upwards of 100 ppm increased worker mortality. Furthermore, while sublethal ([≤] 50 ppm) FPF exposure alone did not affect survival, it increased susceptibility to fungal infection, indicating a synergy between the two stressors. This new report of a synergistic interaction between FPF and pathogens raises further concerns about the impact of novel pesticides and could have important implications for insect conservation.

ecology↗