Biology subjects

Robb, J.

Publications and source records attributed to Robb, J..

4 recordsLinked to original sources

bioRxiv2026

Viral infection patterns in ants are affected by colony structure and phylogenetic lineage

Across ant species, there are differences in how their societies are structured. Single-queened (monogynous) societies only have one reproducing queen in the colony, and new queens disperse and start colonies independently. In multiple-queened (polygynous) societies, the colony instead can contain several reproductive queens, and newborn queens often remain and reproduce within their natal colony. As a result, polygynous societies are comparatively larger, more genetically diverse, and can span large areas through several interconnected nests, whereas monogynous societies are typically smaller in scale. In this study, we investigated how these different social structures, as well as their phylogenetic lineage, affect the diversity (number of virus species per ant sample) and abundance (number of viral sequences per sample) of viruses in ants. We produced pooled RNA sequence libraries from 15 ant species, representing both monogynous and polygynous social structures, and the two largest ant subfamilies: Formicinae and Myrmicinae, with each library containing the RNA of up to 400 individual worker ants from a single population. We identified 168 virus species in total, of which 152 species were new to science. Out of these 168 viruses, 59 were active viruses based on the host immune response. We observed that polygynous ant species harbor a higher diversity of viruses and also tend to have higher virus abundance compared to monogynous species. Also, the ant subfamily Myrmicinae had a higher virus diversity than Formicinae. These findings highlight how social structure and evolutionary history shape viral diversity in ants.

genomics↗

bioRxiv2026

Co-occurrence of Yersinia pestis and other zoonoses during European prehistory

The infection of humans by the causal agent of Plague, Yersinia pestis, has been attested as far back as 5,500 BP. Although the specific patho-mechanism and ultimate origin of the disease caused by these prehistoric genomes remains unclear, the bacterium spread through Europe, likely during the Late Neolithic to Bronze Age (LNBA). In this study, we analysed 9 genomic samples originating from 8 different human individuals dating to around 4950 cal BP from the site of Grotta della Spinosa, Tuscany, Italy. Metagenomic screening of these samples reveals one individual (GSP013) to be co-infected by Yersinia pestis, Erysipelothrix rhusiopathiae, and Hepatitis B virus (HBV). At least three further individuals from the site were infected with HBV, indicating its wider presence within the community. The phylogenetic placement of Y. pestis in GSP013 shows that this strain is closely related to the earliest LNBA Caucasus genomes of the bacterium, basal to later European diversity. This represents the earliest evidence of Y. pestis in the Italian peninsula (and Southern Europe more widely) to date, predating previously discovered genomes by at least 200 years. Furthermore, we retrieved 60 newly reported ancient genomes of Erysipelothrix rhusiopathiae and Erysipelothrix tonsillarum from animals and humans, dating back from 8,300 BP to 100 BP. Of these new genomes, 15 of which stem from individuals known to be infected by Y. pestis. This contributes to our understanding of Y. pestis transmission in prehistoric Europe and possible reservoirs, and offers insights into disease dynamics in communities during the 3rd millennium BCE.

evolutionary biology↗

bioRxiv2025

Immunometabolic state modulation of sequential decision making in patch-foraging mice

Animals have evolved sophisticated behavioural and metabolic adaptations to respond to threats to homeostasis, including resource scarcity and infectious pathogens. Energy deficits associated with lack of food availability and sickness-associated anorexia elicit distinctive hypometabolic states, however how such states are integrated with higher-order cognition is largely unknown. Patch-foraging paradigms have proven useful for deciphering evolutionarily conserved and ethologically grounded insights into cost-benefit decision-making as animals continually deliberate between exploiting and exploring their environment. We developed and extensively validated a touchscreen-based patch-foraging task for mice in which food reward dynamically varied across trials, in a dataset comprising over 111,000 sequential decisions from 35 adult male mice. Contrary to predictions that emphasize the impact of inflammation to blunt effortful reward-driven behaviour, our results demonstrate that systemic lipopolysaccharides-induced inflammation promotes hyper-exploitation by attenuating exploratory choice behaviour in animals interacting with complex food environments. Such behaviour can be seen as a bias towards immediate outcomes, with impulsivity as a feature affecting the weighting of temporal factors. Given the ubiquity of systemic inflammation in numerous infectious, metabolic and psychiatric disorders featuring dysfunctional value- and cost-sensitive behaviour, these results provide insight into how immunometabolic states are linked to altered decision-making.

neuroscience↗

bioRxiv2024

Altruistic disease signalling in ant colonies

Sick individuals often conceal their disease status to group members, thereby preventing social exclusion or aggression. Here, we show that infected ant pupae, on the contrary, actively emit a chemical signal that triggers their own destruction by colony members. In our experiments, this altruistic disease-signalling was performed only by worker but not queen pupae, reflecting differences in their immune capabilities, as worker pupae suffered from extensive pathogen replication whereas queen pupae were able to restrain infection. Inducing others to sacrifice oneself, only if ones own immunity fails, suggests a fine-tuned interplay between individual and social immunity, efficiently achieving whole-colony health.

animal behavior and cognition↗