Latest Articles

• 

  Section: Evolutionary Biology ; Topics: Evolution

  Evaluating the roles of testosterone and sex-linked genes in territorial aggression of sex-reversed XY females in the African pygmy mouse

  Heitzmann, Louise D.;   Perez, Julie; Charbonnier, Romann;   Fichter, Marc; Hautecoeur, Xavier; Deremarque, Théo;   Martin, Agnès O.;   Veyrunes, Frédéric  

  10.24072/pcjournal.786 - Peer Community Journal, Volume 6 (2026), article no. e111

  Get full text PDF

  Sex differences in social aggression are widespread across the animal kingdom, with males typically displaying greater territoriality. While this dimorphism has traditionally been attributed to sex hormones, sex chromosomes can also contribute to it independently of hormonal influence. In the African pygmy mouse, Mus minutoides, naturally occurring sex-reversed XY females (named X*Y due to a mutation on the X chromosome) are highly territorial in comparison to the other female genotypes present in the population (XX and XX*). However, the molecular basis of this phenotype remains unknown. Here, we evaluate molecular factors - known to correlate with aggressiveness - following a standardized behavioural assessment of aggression. We focus on i) the androgen pathway by quantifying testosterone serum levels and expression of its receptor in the brain; ii) the brain dopaminergic system through expression of dopamine-regulating genes, including the sex-determining Sry gene; and iii) neuroendocrine circuits, via vasopressin and oxytocin expression. These systems, although distinct, converge on hypothalamic-limbic circuits that regulate social behaviour and threat responses, providing an integrated framework for the modulation of aggression. Contrary to earlier reports, we found reduced level of aggression in X*Y females, likely to reflect a breeding facility effect. We also observe no correlations between aggressiveness and androgen levels or gene expression of the tested factors. However, our results support a stimulation of the dopaminergic system and of the oxytocin pathway following the agonistic assay suggesting their potential involvement in aggression-related responses. This further supports the idea that aggression is multifactorial. It is shaped by the interaction of several neuroendocrine and neurotransmitter pathways rather than a single determinant.

• 

  Section: Ecotoxicology & Environmental Chemistry ; Topics: Agricultural sciences, Environmental sciences, Ecology

  Citizen-science data reveal drivers of PFAS variability in backyard chicken eggs

  Aarts, Geert;   van Donselaar, Dreas; Lasters, Robin  

  10.24072/pcjournal.816 - Peer Community Journal, Volume 6 (2026), article no. e110

  Get full text PDF

  Per- and polyfluoroalkyl substances (PFAS) are widespread synthetic contaminants that can accumulate in food, such as chicken eggs. Although European Union maximum levels for PFOS, PFOA, PFNA and PFHxS apply to commercialised eggs, backyard chicken egg concentrations frequently exceed these limits. Consequently, in the Netherlands, the national health authority advised against consuming backyard eggs. In response, many chicken owners tested their eggs and openly shared the results through a citizen-science initiative, resulting in the first large, citizen-led PFAS dataset worldwide. The dataset comprises 801 laboratory measurements and includes information on husbandry conditions, including uncovered outdoor space, flock size, feed type and water source. We conducted an exploratory analysis to identify variables associated with variation in the egg concentrations of the EFSA-4 PFAS: PFOS, PFOA, PFNA and PFHxS. Contamination was widespread, with only 36% of samples below EU maximum levels. PFOS dominated, accounting for 87% of the mean summed concentration. Repeated egg sampling revealed substantial temporal variation, indicating that concentrations are dynamic and that single measurements do not reliably reflect human exposure. Generalised additive models showed that surface area of uncovered outdoor space per hen was often the strongest predictor, with larger foraging areas being associated with higher PFAS levels. Larger flock size, higher egg production, and continuous access to food were associated with lower concentrations for three of the four PFAS. Diet and water source were not significantly associated with PFAS levels. Spatial patterns showed decreasing PFAS concentrations with distance from the coast, possibly caused by sea spray aerosol deposition, while PFOA levels were strongly related to distance from a fluorochemical plant, with the highest concentrations downwind. These results suggest that atmospheric deposition shapes PFAS spatial distribution, and uptake by free-ranging hens most likely occurs predominantly via ingestion of contaminated soil invertebrates. Future experimental studies could evaluate mitigation options targeting the soil compartment, including soil modification or limiting soil fauna access through chicken enclosure modifications.

• 

  Section: Ecotoxicology & Environmental Chemistry ; Topics: Environmental sciences, Agricultural sciences, Sustainability science

  France’s Pesticide Load Index: Decreasing Ecotoxicity, Persistent Human Toxicity, Rising Concern For Environmental Fate

  Perrot, Thomas;   Fontaine, Colin;   Möhring, Niklas  

  10.24072/pcjournal.817 - Peer Community Journal, Volume 6 (2026), article no. e109

  Get full text PDF

  Pesticide use has strong adverse effect on biodiversity, ecosystem functioning  and human health . Numerous policies have been proposed to reduce their use and associated risk but evaluations of changes in pesticide risk over time and space are still rare. Here, we evaluate temporal and spatial trends of pesticide risks in France between 2012-2022 using the Pesticide Load Index. The Pesticide Load Index assesses ecotoxicity, human health and fate risks of pesticides, and has been previously employed in Denmark and the UK. The Pesticide Load Index was evaluated accounting for 293 different active substances and 2977 commercial products (99% of sold pesticides mass). We found that pesticide risks have decreased by 29% from 2012 to 2022, mainly due to a reduction in the Ecotoxicity Load (-37.4%) linked to the ban of some of the most toxic active substances, while the Fate Load increased by 13.2% and no significant change was observed in the Human Health Load. Insecticides contributed nearly half (47.6%) of the Pesticide Load Index despite accounting for only 11.2% of the total mass of commercial pesticide products. We also found that the Pesticide Load Index and its three sub-indices were spatially correlated, with higher risks consistently observed in the North and West of France, where beet crops, vineyards, and vegetables cultivation are predominant. Our study identifies priority areas for the mitigation of pesticide  risks, and provides data for public policies to further reduce the use of the most toxic pesticides, focusing not only on ecotoxicity, but also on human health risks and the environmental persistence, mobility and bioaccumulation of pesticides.

• 

  Section: Plants ; Topics: Plant biology, Biology of interactions, Systems biology

  Transcriptional responses of Solanum lycopersicum to three distinct parasites reveal host hubs and networks underlying parasitic successes

  Truch, Julia;   Jaouannet, Maelle; Da Rocha, Martine;   Kulhanek-Fontanille, Emmanuelle; Van Ghelder, Cyril;   Rancurel, Corinne;   Migliore, Olivier; Pere, Arthur; Jaubert, Stephanie;   Coustau, Christine; Galiana, Eric;   Favery, Bruno  

  10.24072/pcjournal.815 - Peer Community Journal, Volume 6 (2026), article no. e108

  Get full text PDF

  Crops face attacks from a wide range of pathogens and pests that deploy various parasitic strategies. All aggressors must manipulate major plant functions, such as immune signaling, hormone pathways, metabolism, and development, to successfully establish themselves and complete their life cycle. Here, we compared the tomato plant’s response to three evolutionary distant pathogens (nematodes, aphids and oomycetes) during compatible interactions using a transcriptomic approach. We identified differentially expressed genes and biological processes, and highlighted potential key host hubs associated with successful parasitism. By integrating recent published datasets, we refined our understanding of the global and tissue-specific mechanisms targeted during compatible interactions and, through co-expression analysis, identified clusters showing shared dysregulation patterns enriched in specific GO terms. Finally, model-to-crop translational analysis using the Arabidopsis interactome network, repositioned tomato candidates within larger interaction networks and emphasized the key positions occupied by some of them. Identifying these pivotal tomato targets is crucial to decipher processes underlying parasitism and, consequently, offers new opportunities to develop sustainable multi-pathogen control strategies.