## 1 Introduction  
Insecticides play a pivotal role in modern agriculture by controlling pest populations and safeguarding crop yields. Among these, juvenile hormone analogs (JHAs) like pyriproxyfen have been substantially adopted due to their ability to disrupt the growth and development of insect pests [1, 2]. However, the sublethal effects of these chemicals on the physiology of emerging and difficult-to-control target pests remain unclear. One example of such insects is the Neotropical brown stalk bug, _Euschistus heros_, a major pest in South American soybean and other row crop fields, causing high-impact economic losses every year [3, 4, 5, 6]. When not sufficiently controlled due to acquired resistance, increased reproductive potential, or, in the case of _E. heros_, both factors [7, 8], insect populations are prone to the sublethal effects, i.e., non-lethal in a direct sense, that occur after exposure. In addition to influencing insect physiology, pesticide residues may also alter interactionsbetween pests and other organisms [9]. While lethal doses and direct mortality have been extensively studied, the more subtle sublethal effects, which can significantly influence pest survival and reproductive success, are often overlooked. Therefore, the need to unravel the sublethal impacts of insecticides is crucial for enhancing pest management strategies and ensuring sustainable agricultural practices. Sublethal effects of insecticides occur when the applied dose is insufficient to achieve full pest control, whether due to incorrect application, ecological and biological traits, or abiotic factors. This can result in altered pest physiology and behavior, influencing population dynamics and potentially leading to resistance development [10]. For _E. heros_, which has developed resistance to pyrethroids and neonicotinoids [5; 8; 11], understanding its baseline biological status under sublethal pyriproxyfen exposure is essential. Additionally, the sublethal effects of insecticides can be strategically used in integrated pest management studies to understand their unintended effects on non-target organisms [10; 12; 13; 14; 15]. This is particularly important for large-scale monocultures like soybean and cotton, where employing insecticides with different modes of action than neurotoxic products is the best alternative [16]. The caveats are that sublethal doses might not provide immediate control and could potentially allow pests to recover and develop resistance if not managed correctly [17]. The status of the studies on sublethal effects lies in the limited research on their biochemical and physiological impacts. Sublethal pyriproxyfen is known to influence several distinct reproductive-related functions in _E. heros_[18; 19; 20] and remarkably affect the levels of macro-elements like calcium (Ca), sulfur (S), chloride (CI), potassium (K), and phosphorus (P) in the hemolymph of _E. heros_[21]. These components serve distinct and crucial roles within various physiological pathways. Remarkably, a generalized increase in macro-elements was observed in the cited study, with males showing higher augmentation than females. Investigating these effects in _E. heros_ can reveal critical insights into how sublethal doses of pyriproxyfen affect metabolic and micro-element profiles, guiding the development of strategies to manage resistant pest populations effectively. The resultant ionic imbalances, due to variations in both macro- and micro-elements, can trigger changes in insect nutrition. For instance, alterations were observed in the basal columnar cells' labyrinth and the cytoplasmic projections of goblet cells in the midgut of _Diatraea saccharalis_[22]. In _Acraea horta_, the balance between lipids and carbohydrates was affected when a sublethal dosage of pyriproxyfen was applied to individual late-stage larvae [23]. These imbalances, often linked with insect development, can impact a range of physiological functions.