Date(s)
le 26 novembre 2025
14h
Lieu(x)
amphi 030 du bâtiment E1
Perturbations environnementales et endocriniennes des soins parentaux : le cas du forficule européen / Environmental and endocrine disruptions in parental care: the case of the European earwig
Résumé : Les soins parentaux sont essentiels à la survie de la descendance, mais on ignore dans quelle mesure ils sont sensibles aux pesticides, dont l’usage est de plus en plus intensif et soulève des inquiétudes pour la biodiversité et les services écosystémiques. Chez les vertébrés, ces comportements sont connus pour être affectés par de telles pressions, et il est possible que des mécanismes similaires existent chez les insectes. Leur régulation hormonale pourrait en effet les rendre particulièrement vulnérables aux polluants considérés comme des perturbateurs endocriniens. Cette thèse a donc utilisé le forficule européen, un auxiliaire de culture exprimant des soins maternels, pour répondre à deux questions : (1) les pesticides perturbent-ils les soins parentaux chez un insecte ? et (2) comment ces soins sont-ils régulés, notamment sur le plan hormonal ?
Nos résultats montrent que ni le glyphosate ni les contextes agricoles étudiés n’affectent l’expression des soins. En revanche, l’exposition à la deltaméthrine entraîne des altérations moléculaires détectées par protéomique, notamment la surexpression de protéines de détoxification à différents moments du cycle, mais ces effets n’ont pas été évalués spécifiquement pendant la période de soins. Ainsi, les données disponibles suggèrent que les soins parentaux pourraient être robustes face aux pressions chimiques, probablement grâce à des mécanismes de régulation qui ne sont pas directement ciblés par les pesticides. La seconde partie de cette thèse consacrée aux régulations hormonales, révèle que l'hormone juvénile est nécessaire au maintien des soins, sans toutefois suffire à les déclencher, ouvrant la possibilité d’un rôle complémentaire des ecdystéroïdes ou de certains neuropeptides.
Dans l’ensemble, nos travaux montrent que, bien que robustes face aux pesticides, les soins parentaux sont finement modulés par des régulations internes, notamment hormonales. Ces recherches pourraient contribuer à optimiser la lutte biologique en mettant en évidence l’importance des mécanismes hormonaux et des comportements parentaux dans la résilience des populations de forficules, un auxiliaire clé en vergers.
Abstract : Parental care is essential for offspring survival, but to what extent it is sensitive to pesticides remains unclear. The increasing use of pesticides raises growing concerns for biodiversity and ecosystem services. In vertebrates, these behaviours are known to be affected by such pressures, and similar mechanisms may exist in insects. Their hormonal regulation could indeed make them particularly vulnerable to pollutants considered as endocrine disruptors. This thesis therefore used the European earwig, a crop auxiliary species exhibiting maternal care, to address two questions: (1) do pesticides disrupt parental care in an insect? and (2) how is this behaviour regulated, particularly at the hormonal level?
Our results show that neither glyphosate nor the agricultural contexts studied affected the expression of care. In contrast, exposure to deltamethrin led to molecular alterations detected through proteomics, notably the overexpression of detoxification proteins at different points in the cycle, although these effects were not specifically assessed during the care period. Thus, the available data suggest that parental care may be robust to chemical pressures, likely due to regulatory mechanisms not directly targeted by pesticides. The second part of this thesis, dedicated to hormonal regulation, reveals that juvenile hormone is required for the maintenance of care, but not sufficient to trigger it, opening the possibility of a complementary role for ecdysteroids or certain neuropeptides.
Overall, our work shows that although robust to pesticides, parental care is finely modulated by internal regulations, particularly hormonal ones. These findings could contribute to optimizing biological control by highlighting the importance of hormonal mechanisms and parental behaviours in the resilience of earwig populations, a key auxiliary species in orchards.
Abstract : Parental care is essential for offspring survival, but to what extent it is sensitive to pesticides remains unclear. The increasing use of pesticides raises growing concerns for biodiversity and ecosystem services. In vertebrates, these behaviours are known to be affected by such pressures, and similar mechanisms may exist in insects. Their hormonal regulation could indeed make them particularly vulnerable to pollutants considered as endocrine disruptors. This thesis therefore used the European earwig, a crop auxiliary species exhibiting maternal care, to address two questions: (1) do pesticides disrupt parental care in an insect? and (2) how is this behaviour regulated, particularly at the hormonal level?
Our results show that neither glyphosate nor the agricultural contexts studied affected the expression of care. In contrast, exposure to deltamethrin led to molecular alterations detected through proteomics, notably the overexpression of detoxification proteins at different points in the cycle, although these effects were not specifically assessed during the care period. Thus, the available data suggest that parental care may be robust to chemical pressures, likely due to regulatory mechanisms not directly targeted by pesticides. The second part of this thesis, dedicated to hormonal regulation, reveals that juvenile hormone is required for the maintenance of care, but not sufficient to trigger it, opening the possibility of a complementary role for ecdysteroids or certain neuropeptides.
Overall, our work shows that although robust to pesticides, parental care is finely modulated by internal regulations, particularly hormonal ones. These findings could contribute to optimizing biological control by highlighting the importance of hormonal mechanisms and parental behaviours in the resilience of earwig populations, a key auxiliary species in orchards.
