An additional mechanism of HSD3B in regulating maternal care behavior in the wolf spiders, neuropeptides

Maternal care is crucial for offspring survival across species. Pardosa pseudoannulata (Araneae, Lycosidae), a natural predator of insect pests in agroecosystems, is known for its hunting abilities and maternal care behaviors, including eggsac-carrying and pulli-carrying behaviors. Pulli-carrying refers to the female spider carrying her offspring (pulli) while exhibiting low levels of cannibalism. Neuropeptides are closely linked to maternal care in animals. In this study, we identified several neuropeptide genes that exhibit expression changes associated with pulli-carrying behavior. Pyrokinin (PK) and sulfakinin (SK) were upregulated, whereas agatoxin-like peptide 4 (ALP4) and gonadotropin-releasing hormone-related peptide (GnRH) were downregulated in pulli-carrying females, compared with non-pulli-carrying females. Behavioral experiments confirmed SK, PK, and ALP4 play regulatory roles in pulli-carrying behavior. Additionally, HSD3B (3β-hydroxysteroid dehydrogenase), a key enzyme in progesterone biosynthesis, influenced pulli-carrying behavior not only through progesterone regulation but also by modulating the expression of PK and SK. Furthermore, pesticide inhibited HSD3B activity, affecting pulli-carrying behavior. Following pesticide treatment, ALP4 was downregulated by two-fold after exposure to difenoconazole and topramezone, suggesting pesticides maybe also impair pulli-carrying behavior by suppressing ALP4. Although it requires more experimental data to verification. This study provides new insights into the neuropeptide mechanisms underlying the regulation of pulli-carrying behavior and highlights the roles of HSD3B and pesticide in modulating maternal care through neuropeptide pathways.