Effect of environmental air pollutants on placental function and pregnancy outcomes: a molecular insight.

Air pollution has become a major health concern, particularly for vulnerable populations such as the elderly, children, and pregnant women. Studies have reported a strong association between prenatal exposure to air pollutants and adverse pregnancy outcomes, including lower birth weight, reduced fetal growth, and an increased frequency of preterm births. This review summarizes the harmful effects of air pollutants, such as particulate matter, on pregnancy and outlines the mechanistic details associated with these adverse outcomes. Particulate pollutant matter may be able to cross the placenta barrier, and alterations in placental functions are central to the detrimental effects of these pollutants. In addition to associations with preeclampsia and gestational hypertension, air pollutants also induce oxidative stress, inflammation, and epigenetic alteration in the placenta. These pollutants can also affect placental homeostasis and endocrine function, contributing to pregnancy complications and possible transgenerational effects. Prenatal air pollution exposure has been linked to reduced cognitive and motor function in infants and newborns, increasing the predisposition to autism spectrum disorders and other neuropsychiatric disorders. This review also summarizes the use of various animal models to study the harmful effects of air pollution on pregnancy and postnatal outcomes. These findings provide valuable insight into the molecular events associated with the process and can aid in risk mitigation and adopting safety measures. Implementing effective environmental protocols and taking appropriate steps may reduce the global disease burden, particularly for developing nations with poor regulatory compliance and large populations of pregnant women.

Differentially expressed microRNAs in brains of adult females may regulate the maternal block of diapause in Sarcophaga bullata.

The maternal regulation of diapause is one type of phenotypic plasticity where the experience of the mother leads to changes in the phenotype of her offspring that impact how well-suited they will be to their future environment. Sarcophaga bullata females with a diapause history produce offspring that cannot enter diapause even if they are reared in a diapause inducing environment. Accumulating evidence suggests that microRNAs regulate diapause and, possibly, maternal regulation of diapause. We found significant differences in the abundances of several microRNAs (miR-125-5p, miR-124-3p, miR-31-5p, and miR-277-3p) in brains dissected from adult female S. bullata that had experienced diapause compared to females with no diapause history. We also found moderate differences in the mRNA expression of the circadian-clock related genes, clock, clockwork orange, and period. MiR-124-3p and miR-31-5p are part of a gene network that includes these circadian clock-related genes. Taken together our results suggest the maternal block of diapause in S. bullata is regulated, at least in part, by a network that includes microRNAs and the circadian clock.

Life table analysis and RNA-Seq reveal hormesis and transgenerational effects of deltamethrin on Aphis gossypii.

BACKGROUND: Deltamethrin, as a highly effective and broad-spectrum insecticide, has been widely used for agricultural pest control such as Aphis gossypii worldwide. Increasing evidence has shown that despite great economic benefits brought by it, deltamethrin has also non-negligible side effects. However, the potential risks and related molecular mechanisms remain largely unclear. RESULTS: Herein, the life table parameters and transcriptome sequencing analyses of the four successive aphid generations were performed to investigate the hormesis and transgenerational effects of deltamethrin on A. gossypii. The life table analysis showed that although the exposure of G0 aphid to 30% lethal concentration (LC30) deltamethrin significantly reduced the net reproduction rate (R0), intrinsic rate of increase (r), and fecundity of G0, but it significantly enhanced the R0 and fecundity of subsequent two generations (G1 and G2) of A. gossypii. Moreover, transcriptomic analyses showed that the signaling pathways related to posttranscriptional regulation (spliceosome), protein processing, longevity regulating, and cell proliferation (DNA replication, homologous recombination and non-homologous end-joining) were significantly up-regulated in G1 or G2 under LC30 deltamethrin treatment. Additionally, we also found that the deltamethrin-sulfoxaflor rotation of G0 and G1 still induced reproductive stimulation, but the reproductive stimulation induced by insecticides rotation treatment was significantly lower than that in the deltamethrin exposure alone. CONCLUSION: Our study demonstrates that sublethal concentrations of deltamethrin significantly enhanced the offspring fecundity of cotton aphid. In addition, our study also reveals the transcriptional response mechanism of hormesis-induced fecundity increase, providing valuable reference for optimizing the application of deltamethrin in integrated pest management. © 2024 Society of Chemical Industry.

Multifaceted paternal exposures before conception and their epigenetic impact on offspring.

As scientific research progresses, there is an increasing understanding of the importance of paternal epigenetics in influencing the health and developmental path of offspring. Prior to conception, the environmental exposures and lifestyle choices of fathers can significantly influence the epigenetic state of sperm, including DNA methylation and histone changes, among other factors. These alterations in epigenetic patterns have the potential for transgenerational transmission potential and may exert profound effects on the biological characteristics of descendants. Paternal epigenetic changes not only affect the regulation of gene expression patterns in offspring but also increase the risk to certain diseases. It is crucial to comprehend the conditions that fathers are exposed to before conception and the potential outcomes of these conditions. This understanding is essential for assessing personal reproductive decisions and anticipating health risks for future generations. This review article systematically summarizes and analyzes current research findings regarding how paternal pre-pregnancy exposures influence offspring as well as elucidates underlying mechanisms, aiming to provide a comprehensive perspective for an enhanced understanding of the impact that paternal factors have on offspring health.

Can acclimation of freshwater rotifers to silver nanoparticles or 5-fluorouracil influence their multi- and transgenerational effects?

Emerging chemical contaminants (ECCs) are among the major environmental threats in present century. A variety of ECCs is released into aquatic environments with little knowledge about their long-term impacts to organisms. We examined the role of acclimation of the freshwater rotifer Brachionus calyciflorus to silver nanoparticles (Ag-NPs) and 5-fluorouracil (5-FU) for determining their ability to deal with these ECCs individually and in mixtures along multiple generations. Additionally, transgenerational effects were also assessed during the recovery phase. Rotifers acclimated at EC10 of Ag-NPs along generations showed a higher ability to deal with higher concentrations of these nanoparticles or 5-FU along generations. Rotifers acclimated to EC10 of 5-FU showed varied responses, as their population growth rates were affected at the initial generations once exposed to higher concentration (EC50) of the same or a new contaminant; however, the rotifers acquired resistance in later generations. The exposure of generational Ag-NP-acclimated rotifers to the mixture of Ag-NPs and 5-FU at EC50 led to a shift from no effects to negative effects along successive generations, suggesting a decrease in resistance, which remained even in the post-exposure recovery phase. Similar transgenerational adverse effects were also observed for the generational Ag-NP-acclimated rotifers released from 5-FU. Rotifers acclimated to 5-FU showed a decrease in population growth rate at the first generation of recovery phase, possibly shifting their optimal environmental conditions when released from contaminants. Overall, our results suggest that rotifers had a high level of plasticity to ECC exposure in freshwaters; however, acclimation can be generic or contaminant dependent.

Reprint: Acclimatization and Adaptive Capacity of Marine Species in a Changing Ocean.

To persist in an ocean changing in temperature, pH and other stressors related to climate change, many marine species will likely need to acclimatize or adapt to avoid extinction. If marine populations possess adequate genetic variation in tolerance to climate change stressors, species might be able to adapt to environmental change. Marine climate change research is moving away from single life stage studies where individuals are directly placed into projected scenarios ('future shock' approach), to focus on the adaptive potential of populations in an ocean that will gradually change over coming decades. This review summarizes studies that consider the adaptive potential of marine invertebrates to climate change stressors and the methods that have been applied to this research, including quantitative genetics, laboratory selection studies and trans- and multigenerational experiments. Phenotypic plasticity is likely to contribute to population persistence providing time for genetic adaptation to occur. Transgenerational and epigenetic effects indicate that the environmental and physiological history of the parents can affect offspring performance. There is a need for long-term, multigenerational experiments to determine the influence of phenotypic plasticity, genetic variation and transgenerational effects on species' capacity to persist in a changing ocean. However, multigenerational studies are only practicable for short generation species. Consideration of multiple morphological and physiological traits, including changes in molecular processes (eg, DNA methylation) and long-term studies that facilitate acclimatization will be essential in making informed predictions of how the seascape and marine communities will be altered by climate change.

Cadmium Exposure in Male Rats Results in Ovarian Granulosa Cell Apoptosis in Female Offspring and Paternal Genetic Effects.

The aim of this study was to investigate whether the damage to male offspring induced by cadmium (Cd) exposure during embryonic period leads to the apoptosis of ovarian granulosa cells (OGCs) in the next generation of female offspring, and whether this apoptosis in the offspring was due to paternal genetic effects. Pregnant Sprague-Dawley (SD) rats were exposed to CdCl2 (0, 0.5, 2.0, or 8.0 mg/kg) by gavage daily for 20 days to produce the filial 1 (F1) generation. F1 males were mated with newly purchased females to produce the F2 generation, and the F3 generation was generated in the same way. No apoptotic bodies were observed in the OGCs of either the F2 or F3 generation as shown by electron microscopy, and a reduced OGC apoptosis rate (detected by flow cytometry) was observed in F2 OGCs from the Cd-exposed group. Moreover, the mRNA (qRT-PCR) levels of Bax and Bcl-2 and the protein (western blotting) level of pro-caspase-8 increased in the F2 generation (p < 0.05). The expression of apoptosis-related miRNAs (qRT-PCR) and methylation of apoptosis-related genes (determined via bisulfite-sequencing PCR) in OGCs were further determined. Compared with those of the controls, the expression patterns of microRNAs (miRNAs) in the F2 offspring were different in the Cd-exposed group. The miR-92a-2-5p expression levels were decreased in both the F2 and F3 generations (p < 0.05), while the average methylation level of apoptosis-related genes did not change significantly (except for individual loci). In summary, this study showed that the paternal genetic intergenerational effect of male Cd exposure during embryonic period induced apoptosis of OGCs in the offspring was weakened, and the transgenerational effect disappeared; nevertheless, intergenerational and transgenerational changes in apoptosis-related genes, epigenetic modifications, DNA methylation, and miRNAs were observed, and may be important for understanding the homeostatic mechanisms of the body to alleviate the intergenerational transmission of Cd-induced damage.

Transgenerational effects of the levonorgestrel-based birth control pill in zebrafish offspring.

The consumption of hormone-derived medicines, such as levonorgestrel (LNG), is increasing worldwide, and its discharge into the environment reaches non-target organisms. In our previous study, we exposed the parental generation of zebrafish to environmentally relevant concentrations of LNG during the developmental phase. Subsequently, they had grown in a tank with clean water until adulthood. Now, we allowed this parental generation to reproduce to obtain F1 progeny unexposed to LGN, in order to analyze the transgenerational effects of parental LNG exposure on the survival and hatching of unexposed F1 embryos and the stress and behavior of F1 larvae. Here, we found decreased survival rates with higher LNG concentrations, providing a transgenerational effect. This highlights the environmental impact of exposure to LNG, causing damage at the individual and population level and affecting the next generation at the beginning of development, impacting qualities in the survival of the species.

Impacts of the cyromazine emergence inhibition procedure of Bactrocera dorsalis on Fopius arisanus: implications for the biological control of diptera pest.

BACKGROUND: Fopius arisanus (Sonan) is an important egg-pupal endoparasitic wasp of Bactrocera dorsalis (Hendel). As traditional method of sorting nonparasitic B. dorsalis from parasitic wasps is labor-intensive, requires specific equipment and poses the risk of spreading fertile hosts, the development of a more convenient, economical and safe sorting procedure is important. RESULTS: The optimal cyromazine emergence inhibition procedure (CEIP) involved facilitating the pupation of B. dorsalis mature larvae (Bdml) in 3 mg kg-1 cyromazine sand substrate (CSS) for 48 h. When the Bdml that had been exposed to F. arisanus during the egg stage were treated with 3-7 mg kg-1 CSS for 48 h, no negative effects on the emergence parameters of parasitoids were observed. Treatment with 3-4 mg kg-1 CSS had insignificant effects on the biological and behavioral parameters of F. arisanus. However, treatment with 5-6 mg kg-1 CSS adversely affected the fecundity and antennating activity of the wasps; specifically, 6 mg kg-1 CSS negatively affected the lifespan and flight ability of wasps. Fortunately, no transgenerational effects on these parameters were observed in the progeny. Regarding the nutrient reserves of both sexes of F. arisanus, significant dose-dependent effects were observed. Moreover, 5-6 mg kg-1 CSS significantly reduced the protein and carbohydrate content in F. arisanus; in particular, 6 mg kg-1 CSS notably reduced the lipid content. CONCLUSION: CEIP provides a more flexible, economical and safe mass-release program for F. arisanus. In addition, it has profound implications for the biological control of other dipteran pests. © 2024 Society of Chemical Industry.

The evolutionary consequences of interactions between the epigenome, the genome and the environment.

The epigenome is the suite of interacting chemical marks and molecules that helps to shape patterns of development, phenotypic plasticity and gene regulation, in part due to its responsiveness to environmental stimuli. There is increasing interest in understanding the functional and evolutionary importance of this sensitivity under ecologically realistic conditions. Observations that epigenetic variation abounds in natural populations have prompted speculation that it may facilitate evolutionary responses to rapid environmental perturbations, such as those occurring under climate change. A frequent point of contention is whether epigenetic variants reflect genetic variation or are independent of it. The genome and epigenome often appear tightly linked and interdependent. While many epigenetic changes are genetically determined, the converse is also true, with DNA sequence changes influenced by the presence of epigenetic marks. Understanding how the epigenome, genome and environment interact with one another is therefore an essential step in explaining the broader evolutionary consequences of epigenomic variation. Drawing on results from experimental and comparative studies carried out in diverse plant and animal species, we synthesize our current understanding of how these factors interact to shape phenotypic variation in natural populations, with a focus on identifying similarities and differences between taxonomic groups. We describe the main components of the epigenome and how they vary within and between taxa. We review how variation in the epigenome interacts with genetic features and environmental determinants, with a focus on the role of transposable elements (TEs) in integrating the epigenome, genome and environment. And we look at recent studies investigating the functional and evolutionary consequences of these interactions. Although epigenetic differentiation in nature is likely often a result of drift or selection on stochastic epimutations, there is growing evidence that a significant fraction of it can be stably inherited and could therefore contribute to evolution independently of genetic change.

Transgenerational reproductive toxicity induced by carboxyl and amino charged microplastics at environmental concentrations in Caenorhabditis elegans: Involvement of histone methylation.

Microplastics, recognized as emerging contaminants, are commonly observed to be charged in the environment, potentially exerting toxic effects on various organisms. However, the transgenerational reproductive toxicity and underlying mechanisms of polystyrene (PS), particularly carboxyl-modified PS (PS-COOH) and amino-modified PS (PS-NH2), remain largely unexplored. In this study, the parental generation (P0) of Caenorhabditis elegans was subjected to environmental concentrations (0.1-100 µg/L) of PS, PS-COOH, and PS-NH2, with subsequent generations (F1-F4) cultured under normal conditions. Exposure to PS-NH2 at concentrations of 10-100 µg/L exhibited more pronounced reproductive toxicity compared to PS or PS-COOH, resulting in decreased brood size, egg ejection rate, number of fertilized eggs, and cell corpses per gonad. Similarly, maternal exposure to 100 µg/L of PS-NH2 induced more severe transgenerational reproductive effects in C. elegans. Significant increases in H3 on lysine 4 dimethylation (H3K4me2) and H3 on lysine 9 trimethylation (H3K9me3) levels were observed in the subsequent generation, concurrent with the transgenerational upregulation of set-30 and met-2 following parental exposure to PS, PS-COOH, and PS-NH2. Correlation analyses revealed significant associations between the expression of these genes with the reproductive ability. Molecular docking studies suggested that PS-NH2 exhibited higher affinity for SET-30 and MET-2. Further analysis demonstrated that transgenerational effects on reproduction were absent in set-30(gk315) and met-2(n4256) mutants, highlighting the pivotal role of set-30 and met-2 in mediating the transgenerational effect. This study provides novel insights into the environmental risks associated with negatively and positively charged microplastics.

Grandfathers-to-Grandsons Transgenerational Transmission of Exercise Positive Effects on Cognitive Performance.

Physical exercise is a robust lifestyle intervention known for its enhancement of cognitive abilities. Nevertheless, the extent to which these benefits can be transmitted across generations (intergenerational inheritance to F1, and transgenerational to F2 and beyond) remains a topic of limited comprehension. We have already shown that cognitive improvements resulting from physical exercise can be inherited from parents to their offspring, proving intergenerational effects. So, we set out to explore whether these enhancements might extend transgenerationally, impacting the F2 generation. In this study, we initially examined the behavioral traits of second generation (F2) male mice, whose grandfathers (F0) had an exercise intervention. Our findings revealed that F2 mice with physically active grandpaternal F0 progenitors displayed significantly improved memory recall, encompassing both spatial and non-spatial information when compared to their counterparts from sedentary F0 progenitors, and proving for the first time the transgenerational inheritance of physical exercise induced cognitive enhancement. Surprisingly, while F2 memory improved (as was the case with F1), adult hippocampal neurogenesis remained unchanged between experimental and control groups (unlike in F1). Additionally, our analysis of small RNA sequences in the hippocampus identified 35 differentially expressed miRNAs linked to important brain function categories. Notably, two of these miRNAs, miRNA-144 and miRNA-298, displayed a robust negative correlation with cognitive performance. These findings highlight the enduring transgenerational transmission of cognitive benefits associated with exercise, even after two generations, suggesting that moderate exercise training can have lasting positive effects, possibly orchestrated by a specific set of miRNAs that exert their influence across multiple generations.

Photoaged Nanopolystyrene Affects Neurotransmission to Induce Transgenerational Neurotoxicity in Caenorhabditis elegans.

Nanopolystyrene (NPS), a frequently employed nanoplastic, is an emerging environmental contaminant known to cause neurotoxicity in various organisms. However, the potential for transgenerational neurotoxic effects, especially from photoaged NPS (P-NPS), remains underexplored. This study investigated the aging of virgin NPS (V-NPS) under a xenon lamp to simulate natural sunlight exposure, which altered the physicochemical characteristics of the NPS. The parental generation (P0) of Caenorhabditis elegans was exposed to environmental concentrations (0.1-100 µg/L) of V-NPS and P-NPS, with subsequent offspring (F1-F4 generations) cultured under NPS-free conditions. Exposure to 100 µg/L P-NPS resulted in more pronounced deterioration in locomotion behavior in the P0 generation compared to V-NPS; this deterioration persisted into the F1-F2 generations but returned to normal in the F3-F4 generations. Additionally, maternal exposure to P-NPS damaged dopaminergic, glutamatergic, and serotonergic neurons in subsequent generations. Correspondingly, there was a significant decrease in the levels of dopamine, glutamate, and serotonin, associated with reduced expression of neurotransmission-related genes dat-1, eat-4, and tph-1 in the P0 and F1-F2 generations. Further analysis showed that the effects of P-NPS on locomotion behavior were absent in subsequent generations of eat-4(ad572), tph-1(mg280), and dat-1(ok157) mutants, highlighting the pivotal roles of these genes in mediating P-NPS-induced transgenerational neurotoxicity. These findings emphasize the crucial role of neurotransmission in the transgenerational effects of P-NPS on locomotion behavior, providing new insights into the environmental risks associated with exposure to photoaged nanoplastics.

Early life stage exposure to fenbuconazole causes multigenerational cardiac developmental defects in zebrafish and potential reasons.

With the increasing use of triazole fungicides in agriculture, triazole pesticides have aroused great concern about their toxicity and ecological risk. The current study investigated the impairments of embryonic exposure to fenbuconazole (FBZ) on cardiac transgenerational toxicity and related mechanisms. The fertilized eggs were exposed to 5, 50 and 500 ng/L FBZ for 72 h, and the larvae were then raised to adulthood in clean water. The adult fish were mated with unexposed fish to produce maternal and paternal F1 and F2 embryos, respectively. The results showed that increased arrhythmia were observed in F0, F1 and F2 larvae. Transcriptome sequencing indicated that the pathway of adrenergic signaling in cardiomyocytes was enriched in F0 and F2 larvae. In both F0 and F1 adult zebrafish hearts, ADRB2 protein expression decreased, and transcription of genes related to cardiac development and Ca2+ homeostasis was downregulated. These alterations might cause cardiac developmental defects. Significantly decreased protein levels of H3K9Ac and H3K14Ac might be linked with the downregulation in transcription of cardiac development genes. Protein‒protein interaction analysis exhibited that the pathway affecting the heart was well inherited in the paternal line. These results provide new ideas for the analysis and prevention of congenital heart disease.

Sex-specific transgenerational effects of diet on offspring life history and physiology.

Dietary variation in males and females can shape the expression of offspring life histories and physiology. However, the relative contributions of maternal and paternal dietary variation to phenotypic expression of latter generations is currently unknown. We provided male and female Drosophila melanogaster grandparents with diets differing in sucrose concentration prior to reproduction, and similarly subjected their grandoffspring to the same treatments. We then investigated the phenotypic consequences of this dietary variation among the grandsons and granddaughters. We observed transgenerational effects of dietary sucrose, mediated through the grandmaternal lineage, which mimic the direct effects of sucrose on lifespan, with opposing patterns across sexes; low sucrose increased female, but decreased male, lifespan. Dietary mismatching of grandoffspring-grandparent diets increased lifespan and reproductive success, and moderated triglyceride levels of grandoffspring, providing insights into the physiological underpinnings of the complex transgenerational effects on life histories.

Association of Fetal Lung Development Disorders with Adult Diseases: A Comprehensive Review.

Fetal lung development is a crucial and complex process that lays the groundwork for postnatal respiratory health. However, disruptions in this delicate developmental journey can lead to fetal lung development disorders, impacting neonatal outcomes and potentially influencing health outcomes well into adulthood. Recent research has shed light on the intriguing association between fetal lung development disorders and the development of adult diseases. Understanding these links can provide valuable insights into the developmental origins of health and disease, paving the way for targeted preventive measures and clinical interventions. This review article aims to comprehensively explore the association of fetal lung development disorders with adult diseases. We delve into the stages of fetal lung development, examining key factors influencing fetal lung maturation. Subsequently, we investigate specific fetal lung development disorders, such as respiratory distress syndrome (RDS), bronchopulmonary dysplasia (BPD), congenital diaphragmatic hernia (CDH), and other abnormalities. Furthermore, we explore the potential mechanisms underlying these associations, considering the role of epigenetic modifications, transgenerational effects, and intrauterine environmental factors. Additionally, we examine the epidemiological evidence and clinical findings linking fetal lung development disorders to adult respiratory diseases, including asthma, chronic obstructive pulmonary disease (COPD), and other respiratory ailments. This review provides valuable insights for healthcare professionals and researchers, guiding future investigations and shaping strategies for preventive interventions and long-term care.

Nano-graphene oxide particles induce inheritable anomalies through altered gene expressions involved in oocyte maturation.

The inheritable impact of exposure to graphene oxide nanoparticles (GO NPs) on vertebrate germline during critical windows of gamete development remain undetermined to date. Here, we analyzed the transgenerational effects of exposure to nano-graphene oxide particles (nGO) synthesized in house with lateral dimensions 300-600 nm and surface charge of -36.8 mV on different developmental stages of germ cells (GCs): (1) during GCs undergoing early development and differentiation, and (2) during GCs undergoing gametogenesis and maturation in adulthood. Biocompatibility analyses in Japanese medaka embryos showed lethality above 1 µg/ml and also an aberrant increase in germ cell count of both males and females at doses below the lethal dose. However, no lethality or anomalies were evident in adults up to 45 µg/ml. Long term exposure of embryos and adults for 21 days resulted in reduced fecundity. This effect was transmitted to subsequent generations, F1 and F2. Importantly, the inheritable effects of nGO in adults were pronounced at a high dose of 10 µg/ml, while 1 µg/ml showed no impact on the germline indicating lower doses used in this study to be safe. Further, expressions of selected genes that adversely affected oocyte maturation were enhanced in F1 and F2 individuals. Interestingly, the inheritance patterns differed corresponding to the stage at which the fish received the exposure.

Insights into adaptive behavioural plasticity from the guppy model system.

Behavioural plasticity allows organisms to respond to environmental challenges on short time scales. But what are the ecological and evolutionary processes that underlie behavioural plasticity? The answer to this question is complex and requires experimental dissection of the physiological, neural and molecular mechanisms contributing to behavioural plasticity as well as an understanding of the ecological and evolutionary contexts under which behavioural plasticity is adaptive. Here, we discuss key insights that research with Trinidadian guppies has provided on the underpinnings of adaptive behavioural plasticity. First, we present evidence that guppies exhibit contextual, developmental and transgenerational behavioural plasticity. Next, we review work on behavioural plasticity in guppies spanning three ecological contexts (predation, parasitism and turbidity) and three underlying mechanisms (endocrinological, neurobiological and genetic). Finally, we provide three outstanding questions that could leverage guppies further as a study system and give suggestions for how this research could be done. Research on behavioural plasticity in guppies has provided, and will continue to provide, a valuable opportunity to improve understanding of the ecological and evolutionary causes and consequences of behavioural plasticity.

Transgenerational effects of triazole fungicides on gene expression and egg compounds in non-exposed offspring: A case study using Red-Legged Partridges (Alectoris rufa).

Triazole fungicides are widely used to treat cereal seeds before sowing. Granivorous birds like the Red-legged Partridge (Alectoris rufa) have high exposure risk because they ingest treated seeds that remain on the field surface. As triazole fungicides can act as endocrine disruptors, affecting sterol synthesis and reproduction in birds several months after exposure, we hypothesized that these effects could also impact subsequent generations of exposed birds. To test this hypothesis, we exposed adult partridges (F0) to seeds treated at commercial doses with four different formulations containing triazoles as active ingredients (flutriafol, prothioconazole, tebuconazole, and a mixture of the latter two), simulating field exposure during late autumn sowing. During the subsequent reproductive season, two to four months after exposure, we examined compound allocation of steroid hormones, cholesterol, vitamins, and carotenoids in eggs laid by exposed birds (F1), as well as the expression of genes encoding enzymes involved in sterol biosynthesis in one-day-old chicks of this F1. One year later, F1 animals were paired again to investigate the expression of the same genes in the F2 chicks. We found changes in the expression of some genes for all treatments and both generations. Additionally, we observed an increase in estrone levels in eggs from partridges treated with flutriafol compared to controls, a decrease in tocopherol levels in partridges exposed to the mixture of tebuconazole and prothioconazole, and an increase in retinol levels in partridges exposed to prothioconazole. Despite sample size limitations, this study provides novel insights into the mechanisms of action of the previously observed effects of triazole fungicide-treated seeds on avian reproduction with evidence that the effects can persist beyond the exposure windows, affecting unexposed offspring of partridges fed with treated seeds. The results highlight the importance of considering long-term chronic effects when assessing pesticide risks to wild birds.

Insects' essential role in understanding and broadening animal medication.

Like humans, animals use plants and other materials as medication against parasites. Recent decades have shown that the study of insects can greatly advance our understanding of medication behaviors. The ease of rearing insects under laboratory conditions has enabled controlled experiments to test critical hypotheses, while their spectrum of reproductive strategies and living arrangements - ranging from solitary to eusocial communities - has revealed that medication behaviors can evolve to maximize inclusive fitness through both direct and indirect fitness benefits. Studying insects has also demonstrated in some cases that medication can act through modulation of the host's innate immune system and microbiome. We highlight outstanding questions, focusing on costs and benefits in the context of inclusive host fitness.