@article{21453,
  abstract     = {1. Collective behaviours are a fascinating study area due to the emergent properties that can only arise in groups of interacting individuals. However, their quantitative study is often impaired by technical difficulties, creating either low-quality and sparse data or impractical data amounts, particularly when capturing large groups over long periods of time. Common challenges arise from recording group members with as little obscuring of each other as possible, as well as in generating manageable data amounts with as high as possible information content.
2. We here provide a multicomponent system that allows to record, analyse and simulate the long-term spatiotemporal activity patterns of insect collectives, especially ant colonies. Our Ant Observing System, ALTAA, comprises a flat-nest design to prevent occlusion of individuals, a recording system running on a low-power single-board-computer, and a set of computer programmes performing quantitative analyses to guide the formation and validation of rules underlying the observed collective patterns. Our system is scalable in that it allows parallel, continuous observation of a high number of colonies using low memory space, with colony maintenance requirements (e.g. feeding, nest humidity) being achieved at lowest possible disturbance by the experimenter.
3. We showcase the potential of the system in a study using the black garden ant, Lasius niger, where we analyse the spatiotemporal effects of different group sizes (1, 6, 10 ants), brood (larvae) presence or absence, as well as of different nest geometries, over a period of 1 week. We show that the ants' motion activity has a weak periodicity in the range of 20 to 120 min promoted by larval presence, and that ants are spatially attracted to their larvae, the water source and the walls. We also find that the presence of nestmates lowers an individual ant's motion activity. Observed data are compared to simulations of the temporal activity of the ants.
4. ALTAA provides a powerful toolkit to quantify and interpret spatial and temporal collective activity patterns in (social) insects over extended periods.},
  author       = {Oh, Jinook and Cremer, Sylvia},
  issn         = {2041-210X},
  journal      = {Methods in Ecology and Evolution},
  publisher    = {Wiley},
  title        = {{ALTAA: Analysis of long-term activity patterns in ant colonies}},
  doi          = {10.1111/2041-210x.70277},
  year         = {2026},
}

@article{20219,
  abstract     = {Reproduction is a fundamental biological process, with organisms reproducing sexually, asexually, and, in some cases, utilizing both modes of reproduction within the same population. Does the ability to reproduce through a combination of asexual and sexual modes offer an evolutionary advantage over relying on either mode alone? Here, we introduce an empirically driven theoretical model to examine the dynamics and interplay between sexual and asexual reproduction in stick insect populations. We analyse it using a novel phase transition approach and corroborate it using published experimental data. We find that the presence of males can either increase or decrease the overall population size. However, maintaining an optimal ratio of parthenogenetic to sexual reproduction is crucial for male resilience, effectively delaying male extinction. Conversely, extreme levels of parthenogenetic reproduction—whether too high or too low—can lead to male extinction, emphasizing the need for a balanced number of virgin females to ensure the persistence of males. Our model also explains male absence in Carausius morosus and persistence in Extatosoma tiaratum. Our findings provide valuable insights into the interplay of reproductive strategies and contribute to broader discussions on the transitions between sexual and asexual reproduction.},
  author       = {Ayalon, Oran and Rajendran, Harikrishnan},
  issn         = {1742-5662},
  journal      = {Journal of the Royal Society Interface},
  number       = {229},
  publisher    = {The Royal Society},
  title        = {{Interplay of asexual and sexual reproduction in bifunctional insects}},
  doi          = {10.1098/rsif.2025.0202},
  volume       = {22},
  year         = {2025},
}

@inproceedings{21076,
  abstract     = {In many scientific experiments, the data annotating cost constraints the pace for testing novel hypotheses. Yet, modern machine learning pipelines offer a promising solution—provided their predictions yield correct conclusions. We focus on Prediction-Powered Causal Inferences (PPCI), i.e., estimating the treatment effect in an unlabeled target experiment, relying on training data with the same outcome annotated but potentially different treatment or effect modifiers. We first show that conditional calibration guarantees valid PPCI at population level. Then, we introduce a sufficient representation constraint transferring validity across experiments, which we propose to enforce in practice in Deconfounded Empirical Risk Minimization, our new model-agnostic training objective. We validate our method on synthetic and real-world scientific data, solving impossible problem instances for Empirical Risk Minimization even with standard invariance constraints. In particular, for the first time, we achieve valid causal inference on a scientific experiment with complex recording and no human annotations, fine-tuning a foundational model on our similar annotated experiment.},
  author       = {Cadei, Riccardo and Demirel, Ilker and De Bartolomeis, Piersilvio and Lindorfer, Lukas and Cremer, Sylvia and Schmid, Cordelia and Locatello, Francesco},
  booktitle    = {39th Annual Conference on Neural Information Processing Systems},
  issn         = {1049-5258},
  location     = {San Diego, CA, United States},
  publisher    = {Neural Information Processing Systems Foundation},
  title        = {{Prediction-powered causal inferences}},
  volume       = {38},
  year         = {2025},
}

@article{18892,
  abstract     = {Sick individuals often conceal their disease status to group members, thereby preventing social exclusion or aggression. Here we show by behavioural, chemical, immunological and infection load analyses that sick ant pupae instead actively emit a chemical signal that in itself is sufficient to trigger their own destruction by colony members. In our experiments, this altruistic disease-signalling was performed only by worker but not queen pupae. The lack of signalling by queen pupae did not constitute cheating behaviour, but reflected their superior immune capabilities. Worker pupae suffered from extensive pathogen replication whereas queen pupae were able to restrain their infection. Our data suggest the evolution of a finely-tuned signalling system in which it is not the induction of an individual’s immune response, but rather its failure to overcome the infection, that triggers pupal signalling for sacrifice. This demonstrates a balanced interplay between individual and social immunity that efficiently achieves whole-colony health.},
  author       = {Dawson, Erika and Hönigsberger, Michaela and Kampleitner, Niklas and Grasse, Anna V and Lindorfer, Lukas and Robb, Jennifer and Beikzadeh Abbasi, Farnaz and Strahodinsky, Florian and Leitner, Hanna and Rajendran, Harikrishnan and Schmitt, Thomas and Cremer, Sylvia},
  issn         = {2041-1723},
  journal      = {Nature Communications},
  publisher    = {Springer Nature},
  title        = {{Altruistic disease signalling in ant colonies}},
  doi          = {10.1038/s41467-025-66175-z},
  volume       = {16},
  year         = {2025},
}

@misc{20471,
  abstract     = {Sick individuals often conceal their disease status to group members, thereby preventing social exclusion or aggression. Here we show by behavioural, chemical, immunological and infection load analyses that sick ant pupae instead actively emit a chemical signal that in itself is sufficient to trigger their own destruction by colony members. In our experiments, this altruistic disease-signalling was performed only by worker but not queen pupae. The lack of signalling by queen pupae did not constitute cheating behaviour, but reflected their superior immune capabilities. Worker pupae suffered from extensive pathogen replication whereas queen pupae were able to restrain their infection. Our data suggest the evolution of a finely-tuned signalling system in which it is not the induction of an individual’s immune response, but rather its failure to overcome the infection, that triggers pupal signalling for sacrifice. This demonstrates a balanced interplay between individual and social immunity that efficiently achieves whole-colony health. },
  author       = {Cremer, Sylvia},
  keywords     = {host-parasite interactions, social insects, social immunity, chemical communication, cooperation},
  publisher    = {Institute of Science and Technology Austria},
  title        = {{Altruistic disease signalling in ant colonies}},
  doi          = {10.15479/AT-ISTA-20471},
  year         = {2025},
}

@phdthesis{19302,
  abstract     = {Social interaction networks of insect colonies facilitate efficient information exchange and
demonstrate adaptive changes to mitigate disease transmission. While circadian rhythms
influence individual behaviour, their role in shaping colony-level defences against pathogens
remains unexplored. Here, we investigate whether social networks of the black garden ant,
Lasius niger, exhibit circadian rhythms and how these rhythms influence disease vulnerability
when colonies are exposed to a pathogen during the day or the night.
We first establish baseline daily variations in activity and network dynamics in pathogen-free
colonies, revealing constitutive daily fluctuations in disease susceptibility. Subsequently, we
examine pathogen-induced changes in sanitary care and network dynamics by exposing
foragers to a natural pathogen (Metarhizium brunneum) during either the day or the night.
Individual pathogen loads were measured after a nine-hour post-exposure period to evaluate
transmission outcomes.
Our results demonstrate that diurnal ant colonies maintain robust circadian patterns in network
properties while flexibly adapting to pathogen exposure. Ants upregulate sanitary care
irrespective of exposure timing, prioritising the protection of the valuable colony centre
consisting of nurses and the queen. These findings underscore the robustness and adaptability
of ant colonies in balancing circadian rhythms with effective social immune responses.},
  author       = {Sartoris, Linda},
  issn         = {2663-337X},
  pages        = {85},
  publisher    = {Institute of Science and Technology Austria},
  title        = {{The effect of circadian rhythm on organisational immunity of ant colonies}},
  doi          = {10.15479/AT-ISTA-19302},
  year         = {2025},
}

@phdthesis{19993,
  abstract     = {Ants are frequently challenged by different pathogens, which they counter with
individual and collective responses. Usually, the pathogens like fungi or viruses are
solitary and passive pathogens transmitted from host to host. Here, we use a nematobacterial pathogen complex to study worm-borne disease in black garden ants. These
entomopathogenic nematodes are active parasites with an own behavior and chasing
pray.
In the first chapter, we investigated the basic biology of the host-pathogen relationship.
We tested different ant life stages and found that adult ants display defense behaviors
and are generally resistant to nematode infection, whereas brood is highly susceptible.
In the case of worker pupae, we found a slight protective effect of the cocoon. When
larvae are accompanied by adults, meaning a queen or a group of workers, survival is
significantly enhanced. Moreover, we found that nematodes can transmit from infected
cadavers to healthy worker larvae, confirming a transmissible disease in ants. Again,
worker presence significantly reduces transmission risk. In the end, we were also able
to disentangle the pathogen system and investigate the pathogenic effect of the
bacterial and nematode components.
In the second chapter, we studied the effect of multiple infections in adult queens and
queen larvae. By multiple exposures in the mode of coinfection and superinfections,
we wanted to assess the detrimental effect of combined fungal and nematode
exposure to better understand how the pathogens interact with each other in an ant
host. We found instances where combined exposure lead to higher mortality in a given
time frame in both, adult queens and queen larvae.
Overall entomopathogenic nematodes are a promising model to study worm infections
in ants which extend our knowledge on collective disease defense.},
  author       = {Strahodinsky, Florian},
  issn         = {2663-337X},
  pages        = {138},
  publisher    = {Institute of Science and Technology Austria},
  title        = {{Social immunity in a tri-partite host-pathogen relationship}},
  doi          = {10.15479/AT-ISTA-19993},
  year         = {2025},
}

@article{14478,
  abstract     = {Entire chromosomes are typically only transmitted vertically from one generation to the next. The horizontal transfer of such chromosomes has long been considered improbable, yet gained recent support in several pathogenic fungi where it may affect the fitness or host specificity. To date, it is unknown how these transfers occur, how common they are and whether they can occur between different species. In this study, we show multiple independent instances of horizontal transfers of the same accessory chromosome between two distinct strains of the asexual entomopathogenic fungus<jats:italic>Metarhizium robertsii</jats:italic>during experimental co-infection of its insect host, the Argentine ant. Notably, only the one chromosome – but no other – was transferred from the donor to the recipient strain. The recipient strain, now harboring the accessory chromosome, exhibited a competitive advantage under certain host conditions. By phylogenetic analysis we further demonstrate that the same accessory chromosome was horizontally transferred in a natural environment between<jats:italic>M. robertsii</jats:italic>and another congeneric insect pathogen,<jats:italic>M. guizhouense</jats:italic>. Hence horizontal chromosome transfer is not limited to the observed frequent events within species during experimental infections but also occurs naturally across species. The transferred accessory chromosome contains genes that might be involved in its preferential horizontal transfer, encoding putative histones and histone-modifying enzymes, but also putative virulence factors that may support its establishment. Our study reveals that both intra- and interspecies horizontal transfer of entire chromosomes is more frequent than previously assumed, likely representing a not uncommon mechanism for gene exchange.</jats:p><jats:sec><jats:title>Significance Statement</jats:title><jats:p>The enormous success of bacterial pathogens has been attributed to their ability to exchange genetic material between one another. Similarly, in eukaryotes, horizontal transfer of genetic material allowed the spread of virulence factors across species. The horizontal transfer of whole chromosomes could be an important pathway for such exchange of genetic material, but little is known about the origin of transferable chromosomes and how frequently they are exchanged. Here, we show that the transfer of accessory chromosomes - chromosomes that are non-essential but may provide fitness benefits - is common during fungal co-infections and is even possible between distant pathogenic species, highlighting the importance of horizontal gene transfer via chromosome transfer also for the evolution and function of eukaryotic pathogens.},
  author       = {Habig, Michael and Grasse, Anna V and Müller, Judith and Stukenbrock, Eva H. and Leitner, Hanna and Cremer, Sylvia},
  issn         = {1091-6490},
  journal      = {Proceedings of the National Academy of Sciences of the United States of America},
  number       = {11},
  publisher    = {National Academy of Sciences},
  title        = {{Frequent horizontal chromosome transfer between asexual fungal insect pathogens}},
  doi          = {10.1073/pnas.2316284121},
  volume       = {121},
  year         = {2024},
}

@article{14479,
  abstract     = {In animals, parasitic infections impose significant fitness costs.1,2,3,4,5,6 Infected animals can alter their feeding behavior to resist infection,7,8,9,10,11,12 but parasites can manipulate animal foraging behavior to their own benefits.13,14,15,16 How nutrition influences host-parasite interactions is not well understood, as studies have mainly focused on the host and less on the parasite.9,12,17,18,19,20,21,22,23 We used the nutritional geometry framework24 to investigate the role of amino acids (AA) and carbohydrates (C) in a host-parasite system: the Argentine ant, Linepithema humile, and the entomopathogenic fungus, Metarhizium brunneum. First, using 18 diets varying in AA:C composition, we established that the fungus performed best on the high-amino-acid diet 1:4. Second, we found that the fungus reached this optimal diet when given various diet pairings, revealing its ability to cope with nutritional challenges. Third, we showed that the optimal fungal diet reduced the lifespan of healthy ants when compared with a high-carbohydrate diet but had no effect on infected ants. Fourth, we revealed that infected ant colonies, given a choice between the optimal fungal diet and a high-carbohydrate diet, chose the optimal fungal diet, whereas healthy colonies avoided it. Lastly, by disentangling fungal infection from host immune response, we demonstrated that infected ants foraged on the optimal fungal diet in response to immune activation and not as a result of parasite manipulation. Therefore, we revealed that infected ant colonies chose a diet that is costly for survival in the long term but beneficial in the short term—a form of collective self-medication.},
  author       = {Csata, Eniko and Perez-Escudero, Alfonso and Laury, Emmanuel and Leitner, Hanna and Latil, Gerard and Heinze, Juerge and Simpson, Stephen and Cremer, Sylvia and Dussutour, Audrey},
  issn         = {1879-0445},
  journal      = {Current Biology},
  number       = {4},
  pages        = {902--909.e6},
  publisher    = {Elsevier},
  title        = {{Fungal infection alters collective nutritional intake of ant colonies}},
  doi          = {10.1016/j.cub.2024.01.017},
  volume       = {34},
  year         = {2024},
}

@article{18171,
  abstract     = {Defense against pathogens and parasites requires substantial investment of energy and resources on part of the host. This makes the host immune function dependent on availability and accessibility of resources. A resource deprived host is therefore expected to be more susceptible to infections, although empirical results do not always align with this prediction. Limiting host access to resources can additionally impact within-host pathogen numbers, either directly by altering the amount of resources available to the pathogens for proliferation or indirectly by altering the efficiency of the host immune system. We tested for the effects of host starvation (complete deprivation of resources) on susceptibility to bacterial pathogens, and within-host pathogen proliferation, in Drosophila melanogaster females. Our results show that starvation increases post-infection mortality of the host, but in a pathogen-specific manner. This increase in mortality is always accompanied by increased within-host pathogen proliferation. We therefore propose that starvation compromises host resistance to bacterial infections in Drosophila melanogaster females thereby increasing susceptibility to infections.},
  author       = {Basu, Aabeer and Singh, Aparajita and Sehgal, Suhaas and Madaan, Tanvi and Prasad, Nagaraj Guru},
  issn         = {1096-0805},
  journal      = {Journal of Invertebrate Pathology},
  number       = {11},
  publisher    = {Elsevier},
  title        = {{Starvation increases susceptibility to bacterial infection and promotes systemic pathogen proliferation in Drosophila melanogaster females}},
  doi          = {10.1016/j.jip.2024.108209},
  volume       = {207},
  year         = {2024},
}

@inproceedings{18847,
  abstract     = {Machine Learning and AI have the potential to transform data-driven
scientific discovery, enabling accurate predictions for several scientific
phenomena. As many scientific questions are inherently causal, this paper looks
at the causal inference task of treatment effect estimation, where the outcome
of interest is recorded in high-dimensional observations in a Randomized
Controlled Trial (RCT). Despite being the simplest possible causal setting and
a perfect fit for deep learning, we theoretically find that many common choices
in the literature may lead to biased estimates. To test the practical impact of
these considerations, we recorded ISTAnt, the first real-world benchmark for
causal inference downstream tasks on high-dimensional observations as an RCT
studying how garden ants (Lasius neglectus) respond to microparticles applied
onto their colony members by hygienic grooming. Comparing 6 480 models
fine-tuned from state-of-the-art visual backbones, we find that the sampling
and modeling choices significantly affect the accuracy of the causal estimate,
and that classification accuracy is not a proxy thereof. We further validated
the analysis, repeating it on a synthetically generated visual data set
controlling the causal model. Our results suggest that future benchmarks should
carefully consider real downstream scientific questions, especially causal
ones. Further, we highlight guidelines for representation learning methods to
help answer causal questions in the sciences.},
  author       = {Cadei, Riccardo and Lindorfer, Lukas and Cremer, Sylvia and Schmid, Cordelia and Locatello, Francesco},
  booktitle    = {ICML 2024 Workshop AI4Science},
  publisher    = {Curran Associates},
  title        = {{Smoke and mirrors in causal downstream tasks}},
  volume       = {38},
  year         = {2024},
}

@misc{18895,
  abstract     = {ISTAnt is a new ecological dataset for social immunity and represents the first real-world benchmark for causal inference downstream tasks on high-dimensional observations. It analyzes grooming behavior in the ant Lasius neglectus in groups of three worker ants. The workers for the experiment were obtained from their laboratory stock colony, which had been collected from the field in 2022 in the Botanical Garden Jena, Germany. Ant collection and all experimental work were performed in compliance with international, national and institutional regulations and ethical guidelines. For the experiment, the body surface of one of the three ants was treated with a suspension of either of two microparticle types (diameter ~5 µm) to induce grooming by the two nestmates, which were individually color-coded by application of a dot of blue or orange paint, respectively. The three ants were housed in small plastic containers (diameter 28mm, height 30mm) with moistened, plastered ground and the interior walls covered with PTFE (polytetrafluoroethane) to hamper climbing by the ants. Filming occurred in a temperature- and humidity-controlled room at 23°C within a custom-made filming box with controlled lighting and ventilation conditions. We set up nine ant groups at a time (always containing both treatments) and placed them randomly on positions 1-9 marked on the floor in a 3x3 grid, about 3mm from each other. The experiment was performed on two consecutive days. Videos were acquired using a USB camera (FLIR blackfly S BFS-U3-120S4C, Teledyne FLIR) with a high-performance lens (HP Series 25mm Focal Length, Edmund optics 86-572) in OBS studio 29.0.0 \citep{bailey2017obs} at a framerate of 30 FPS and a resolution of 2500x2500 pixels. From each original video (105x105 mm), we generated nine individual videos .mkv (each ~32x32 mm, 770x770 pixels) by determining exact coordinates per container from one frame in GIMP 2.10.36 and cropping of the videos with FFmpeg 6.1.1. Annotation was performed over two consecutive days by three observers who had not been involved in the experimental setup or recording and were unaware of the treatment assignments to ensure bias-free behavioral annotation. They annotated the behavior of the ants during video observations, using custom-made software that saves the start and end frames of behaviors marked in a .csv file (see 'annotations' folder). In one of the videos, one of the nestmates' legs got inadvertently stuck to its body surface during the color-coding, interfering with its behavior, so the video was discarded. This left 44 videos from 5 independent setups (n=24 of treatment 1 and n=20 of treatment 2) of 10 minutes each for a total of 792 000 annotated frames (see 'video' folder). For each video, we provide the following information: the number of the set to which it belongs (1-5); the number of the position within the set reflecting the position of the ant group under the camera (1-9), for which we also provide ‘coordinates’ in the 3x3 grid (taking values -1/0/1 for both X and Y axis); treatment (1 or 2); the hour of the day when the recording was started (in 24h CEST); experimental day (A or B); the top left coordinate of the cropping square from the original video (CropX/CropY); the person annotating the video (given as A, B, C); the date of annotation (1: first day, 2: second day) and in which order the videos were annotated by each person, both reflecting a possible training effect of the person (see 'experiments_settings.csv' file).},
  author       = {Cadei, Riccardo and Locatello, Francesco and Cremer, Sylvia M and Lindorfer, Lukas and Schmid, Cordelia},
  publisher    = {Institute of Science and Technology Austria},
  title        = {{ISTAnt}},
  doi          = {10.6084/M9.FIGSHARE.26484934.V2},
  year         = {2024},
}

@article{17461,
  abstract     = {Socially living animals can counteract disease through cooperative defences, leading to social immunity that collectively exceeds the sum of individual defences. In superorganismal colonies of social insects with permanent caste separation between reproductive queen(s) and nonreproducing workers, workers are obligate altruists and thus engage in unconditional social immunity, including highly specialised and self-sacrificial hygiene behaviours. Contrastingly, cooperation is facultative in cooperatively breeding families, where all members are reproductively totipotent but offspring transiently forgo reproduction to help their parents rear more siblings. Here, helpers should either express condition-dependent social immunity or disperse to pursue independent reproduction. We advocate inclusive fitness theory as a framework to predict when and how indirect fitness gains may outweigh direct fitness costs, thus favouring conditional social immunity.},
  author       = {Cremer, Sylvia and Pull, Christopher},
  issn         = {1471-5007},
  journal      = {Trends in Parasitology},
  number       = {9},
  pages        = {780--787},
  publisher    = {Elsevier},
  title        = {{Unconditional versus condition-dependent social immunity}},
  doi          = {10.1016/j.pt.2024.07.014},
  volume       = {40},
  year         = {2024},
}

@article{12469,
  abstract     = {Hosts can carry many viruses in their bodies, but not all of them cause disease. We studied ants as a social host to determine both their overall viral repertoire and the subset of actively infecting viruses across natural populations of three subfamilies: the Argentine ant (Linepithema humile, Dolichoderinae), the invasive garden ant (Lasius neglectus, Formicinae) and the red ant (Myrmica rubra, Myrmicinae). We used a dual sequencing strategy to reconstruct complete virus genomes by RNA-seq and to simultaneously determine the small interfering RNAs (siRNAs) by small RNA sequencing (sRNA-seq), which constitute the host antiviral RNAi immune response. This approach led to the discovery of 41 novel viruses in ants and revealed a host ant-specific RNAi response (21 vs. 22 nt siRNAs) in the different ant species. The efficiency of the RNAi response (sRNA/RNA read count ratio) depended on the virus and the respective ant species, but not its population. Overall, we found the highest virus abundance and diversity per population in Li. humile, followed by La. neglectus and M. rubra. Argentine ants also shared a high proportion of viruses between populations, whilst overlap was nearly absent in M. rubra. Only one of the 59 viruses was found to infect two of the ant species as hosts, revealing high host-specificity in active infections. In contrast, six viruses actively infected one ant species, but were found as contaminants only in the others. Disentangling spillover of disease-causing infection from non-infecting contamination across species is providing relevant information for disease ecology and ecosystem management.},
  author       = {Viljakainen, Lumi and Fürst, Matthias and Grasse, Anna V and Jurvansuu, Jaana and Oh, Jinook and Tolonen, Lassi and Eder, Thomas and Rattei, Thomas and Cremer, Sylvia},
  issn         = {1664-302X},
  journal      = {Frontiers in Microbiology},
  publisher    = {Frontiers},
  title        = {{Antiviral immune response reveals host-specific virus infections in natural ant populations}},
  doi          = {10.3389/fmicb.2023.1119002},
  volume       = {14},
  year         = {2023},
}

@article{12543,
  abstract     = {Treating sick group members is a hallmark of collective disease defence in vertebrates and invertebrates alike. Despite substantial effects on pathogen fitness and epidemiology, it is still largely unknown how pathogens react to the selection pressure imposed by care intervention. Using social insects and pathogenic fungi, we here performed a serial passage experiment in the presence or absence of colony members, which provide social immunity by grooming off infectious spores from exposed individuals. We found specific effects on pathogen diversity, virulence and transmission. Under selection of social immunity, pathogens invested into higher spore production, but spores were less virulent. Notably, they also elicited a lower grooming response in colony members, compared with spores from the individual host selection lines. Chemical spore analysis suggested that the spores from social selection lines escaped the caregivers’ detection by containing lower levels of ergosterol, a key fungal membrane component. Experimental application of chemically pure ergosterol indeed induced sanitary grooming, supporting its role as a microbe-associated cue triggering host social immunity against fungal pathogens. By reducing this detection cue, pathogens were able to evade the otherwise very effective collective disease defences of their social hosts.},
  author       = {Stock, Miriam and Milutinovic, Barbara and Hönigsberger, Michaela and Grasse, Anna V and Wiesenhofer, Florian and Kampleitner, Niklas and Narasimhan, Madhumitha and Schmitt, Thomas and Cremer, Sylvia},
  issn         = {2397-334X},
  journal      = {Nature Ecology and Evolution},
  pages        = {450--460},
  publisher    = {Springer Nature},
  title        = {{Pathogen evasion of social immunity}},
  doi          = {10.1038/s41559-023-01981-6},
  volume       = {7},
  year         = {2023},
}

@misc{12693,
  abstract     = {See Readme File for further information.},
  author       = {Cremer, Sylvia},
  publisher    = {Institute of Science and Technology Austria},
  title        = {{Source data for Metzler et al, 2023: Trade-offs between immunity and competitive ability in fighting ant males }},
  doi          = {10.15479/AT:ISTA:12693},
  year         = {2023},
}

@article{12696,
  abstract     = {Background: Fighting disease while fighting rivals exposes males to constraints and tradeoffs during male-male competition. We here tested how both the stage and intensity of infection with the fungal pathogen Metarhizium robertsii interfered with fighting success in Cardiocondyla obscurior ant males. Males of this species have evolved long lifespans during which they can gain many matings with the young queens of the colony, if successful in male-male competition. Since male fights occur inside the colony, the outcome of male-male competition can further be biased by interference of the colony’s worker force.
Results: We found that severe, but not yet mild, infection strongly impaired male fighting success. In late-stage infection, this could be attributed to worker aggression directed towards the infected rather than the healthy male and an already very high male morbidity even in the absence of fighting. Shortly after pathogen exposure, however, male mortality was particularly increased during combat. Since these males mounted a strong immune response, their reduced fighting success suggests a trade-off between immune investment and competitive ability already early in the infection. Even if the males themselves showed no difference in the number of attacks they raised against their healthy rivals across infection stages and levels, severely infected males were thus losing in male-male competition from an early stage of infection on.
Conclusions: Males of the ant C. obscurior have evolved high immune investment, triggering an effective immune response very fast after fungal exposure. This allows them to cope with mild pathogen exposures without cost to their success in male-male competition, and hence to gain multiple mating opportunities with the emerging virgin queens of the colony. Under severe infection, however, they are weak fighters and rarely survive a combat already at early infection when raising an immune response, as well as at progressed infection, when they are morbid and preferentially targeted by worker aggression. Workers thereby remove males that pose a future disease threat by biasing male-male competition. Our study thus revealed a novel social immunity mechanism how social insect workers protect the colony against disease risk.},
  author       = {Metzler, Sina and Kirchner, Jessica and Grasse, Anna V and Cremer, Sylvia},
  issn         = {2730-7182},
  journal      = {BMC Ecology and Evolution},
  publisher    = {Springer Nature},
  title        = {{Trade-offs between immunity and competitive ability in fighting ant males}},
  doi          = {10.1186/s12862-023-02137-7},
  volume       = {23},
  year         = {2023},
}

@article{12765,
  abstract     = {Animals exhibit a variety of behavioural defences against socially transmitted parasites. These defences evolved to increase host fitness by avoiding, resisting or tolerating infection.
Because they can occur in both infected individuals and their uninfected social partners, these defences often have important consequences for the social group.
Here, we discuss the evolution and ecology of anti-parasite behavioural defences across a taxonomically wide social spectrum, considering colonial groups, stable groups, transitional groups and solitary animals.
We discuss avoidance, resistance and tolerance behaviours across these social group structures, identifying how social complexity, group composition and interdependent social relationships may contribute to the expression and evolution of behavioural strategies.
Finally, we outline avenues for further investigation such as approaches to quantify group-level responses, and the connection of the physiological and behavioural response to parasites in different social contexts.},
  author       = {Stockmaier, Sebastian and Ulrich, Yuko and Albery, Gregory F. and Cremer, Sylvia and Lopes, Patricia C.},
  issn         = {1365-2435},
  journal      = {Functional Ecology},
  number       = {4},
  pages        = {809--820},
  publisher    = {British Ecological Society},
  title        = {{Behavioural defences against parasites across host social structures}},
  doi          = {10.1111/1365-2435.14310},
  volume       = {37},
  year         = {2023},
}

@misc{12945,
  abstract     = {basic data for use in code for experimental data analysis for manuscript under revision: 
Dynamic pathogen detection and social feedback shape collective hygiene in ants
Casillas-Pérez B, Boďová K, Grasse AV, Tkačik G, Cremer S},
  author       = {Cremer, Sylvia},
  keywords     = {collective behavior, host-pathogen interactions, social immunity, epidemiology, social insects, probabilistic modeling},
  publisher    = {Institute of Science and Technology Austria},
  title        = {{Data from: "Dynamic pathogen detection and social feedback shape collective hygiene in ants" }},
  doi          = {10.15479/AT:ISTA:12945},
  year         = {2023},
}

@article{12961,
  abstract     = {Two notes separated by a doubling in frequency sound similar to humans. This “octave equivalence” is critical to perception and production of music and speech and occurs early in human development. Because it also occurs cross-culturally, a biological basis of octave equivalence has been hypothesized. Members of our team previousy suggested four human traits are at the root of this phenomenon: (1) vocal learning, (2) clear octave information in vocal harmonics, (3) differing vocal ranges, and (4) vocalizing together. Using cross-species studies, we can test how relevant these respective traits are, while controlling for enculturation effects and addressing questions of phylogeny. Common marmosets possess forms of three of the four traits, lacking differing vocal ranges. We tested 11 common marmosets by adapting an established head-turning paradigm, creating a parallel test to an important infant study. Unlike human infants, marmosets responded similarly to tones shifted by an octave or other intervals. Because previous studies with the same head-turning paradigm produced differential results to discernable acoustic stimuli in common marmosets, our results suggest that marmosets do not perceive octave equivalence. Our work suggests differing vocal ranges between adults and children and men and women and the way they are used in singing together may be critical to the development of octave equivalence.},
  author       = {Wagner, Bernhard and Šlipogor, Vedrana and Oh, Jinook and Varga, Marion and Hoeschele, Marisa},
  issn         = {1467-7687},
  journal      = {Developmental Science},
  number       = {5},
  publisher    = {Wiley},
  title        = {{A comparison between common marmosets (Callithrix jacchus) and human infants sheds light on traits proposed to be at the root of human octave equivalence}},
  doi          = {10.1111/desc.13395},
  volume       = {26},
  year         = {2023},
}