Biology subjects

Kever, M.

Publications and source records attributed to Kever, M..

3 recordsLinked to original sources

bioRxiv2025

The Genomic Basis of Social Parasitism: A Geographical Mosaic of Behavioural, Chemical, and Environmental Adaptations in a Widespread Host-Parasite System

Coevolutionary dynamics in host-parasite systems are driven by reciprocal selection and environmental pressures. When parasite and host are closely related and have similar evolutionary potentials, evolution may follow parallel trajectories, affecting the same traits and underlying genes. We investigated coevolution and its genomic basis in the dulotic ant parasite Temnothorax americanus and its host T. longispinosus across a broad climatic gradient using population genomics, genome-wide association and transcriptome analyses. Population genomics revealed a striking contrast: panmictic host populations versus structured parasite populations, consistent with geographic mosaic dynamics. Genomic responses to parasite prevalence were strongly asymmetric: hosts showed strong selection on immune and structural defence genes, potentially with pleiotropic social functions. Parasites exhibited weaker signals, often in regulatory genes linked to behavioural shifts critical for raiding. Both species displayed shared genomic signatures of climate adaptation (e.g., desiccation resistance, stress response), suggesting convergent physiological responses. Genes associated with host-parasite encounters (mechanosensation, circadian rhythms, venom) also showed parallel selection. Behavioural traits such as aggression showed limited genomic signals but potentially higher transcriptional plasticity. Associations with chemical traits revealed shared selection on genes involved in cuticular hydrocarbon biosynthesis and chemosensory perception, indicating evolutionary coupling of signal production and perception. Constitutive gene expression patterns diverged: host expression correlated with parasite prevalence, while parasite expression was more strongly linked to climate, reflecting contrasting regulatory pressures. Our study demonstrates how differing population structures, asymmetric reciprocal selection, and environmental context shape divergent genomic trajectories of coadaptation, reflecting distinct evolutionary architectures across a heterogeneous landscape.

evolutionary biology↗

bioRxiv2023

Age- and caste-independent piRNAs in the germline and miRNA profiles linked to caste and fecundity in the ant Temnothorax rugatulus

Social insects are models for phenotypic plasticity: the generation of different phenotypes from the same genotype. Ant queens and workers differ not only in their morphology and behaviour, but also in their fecundity and lifespan, which is often several times higher in queens. However, the gene regulatory mechanisms underlying these differences are not yet well understood. Since ant queens can live and reproduce for more than two decades, they need to protect their germline from the activity of transposable elements (TEs). This protection may be redundant in short-lived, often sterile workers. We have analysed the expression of two protective classes of smallRNAs, microRNAs (miRNAs) and Piwi-interacting RNAs (piRNAs), in different tissues, castes, and age classes of the ant species Temnothorax rugatulus. We show that piRNAs are particularly active in the ovaries of queens. TEs are clear targets of the piRNAs in this ant species, and piRNA-specific sequence signatures in the ovaries of all queens regardless of age indicate that young and old queens have similarly active piRNA pathways. Interestingly, the reduced ovaries of the workers also showed the same level of piRNA activity. This was not only the case in young, fertile workers from queenless nests, but also in the presumably older foragers, which have almost completely regressed ovaries. These findings suggest that the germline in these ants is invariably protected by piRNA activity, irrespective of ovarian development. The brain and thorax of queens also contained piRNAs, but at lower levels, and the piRNA-specific ping-pong signatures were strongly reduced in these tissues. We also annotated and analysed miRNAs in different tissues. We confidently detected the expression of 304 miRNAs. Of these, 10 were enriched in the brain and three to the thorax, whereas 83 were specific to the ovaries. 105 miRNAs were found to be expressed in all three tissues. We also identified miRNAs whose expression potentially is related to ant caste, fecundity, and age, suggesting that caste-specific gene activity may be regulated in part by miRNAs. In contrast, our studies of piRNA activity indicate similar profiles across caste, fecundity and age groups, but strong tissue specificity with the highest piRNA mediated TE protection in the germline.

ecology↗

bioRxiv2022

What doesn't kill you makes you live longer - Longevity of a social host linked to parasite proteins

Parasites with complex lifecycles often manipulate the phenotype of their intermediate hosts to increase the probability of transmission to their definitive hosts. Infection with Anomotaenia brevis, a cestode that uses Temnothorax nylanderi ants as intermediate hosts, leads to a multiple-fold extension of host lifespan and to changes in behaviour, morphology, and colouration. The mechanisms behind these changes are unknown, as is whether the increased longevity is achieved through parasite manipulation. Here we demonstrate that the parasite releases proteins into its host with functions that might explain the observed changes. These parasitic proteins make up a substantial portion of the proteome of the hosts haemolymph, and thioredoxin peroxidase and superoxide dismutase, two antioxidants, exhibited the highest abundances among them. The largest part of the secreted proteins could not be annotated, indicating they are either novel or severely altered during recent coevolution to function in host manipulation. We also detected shifts in the hosts proteome with infection, in particular an overabundance of vitellogenin-like-A in infected ants, a protein that regulates division of labour in Temnothorax ants, which could explain the observed behavioural changes. Our results thus point at two different strategies likely employed by this parasite to manipulate its host - by secretion of proteins with immediate influence on the hosts phenotype and by altering the hosts translational activity. Our findings reveal the intricate molecular interplay required to influence the phenotype of a host and shed light on potential signalling pathways and genes involved in parasite-host communication.

evolutionary biology↗