Imidacloprid-Induced Developmental Retardation in Bee Larvae: A Potential Role of Energy Depletion

The Dynamic Energy Budget (DEB) theory proposes that environmental stressors can significantly disrupt an organism's energy balance (Kooijman, 2009). Increased activity in response to stress further depletes an organism's energy reserves. Animals often expend significant energy, including glycogen and protein, to cope with increased energy demands resulting from stressors like pesticides (Bouayad et al., 2012b; Matsukura et al., 2008).

This study investigated larvae exposed to imidacloprid and exhibiting developmental retardation. Significant negative correlations were observed between energy reserves (ATP, total protein, and total glycogen) and antioxidants and detoxification (Fig. 7), suggesting a close link between imidacloprid-induced energy reduction and CYP450 detoxification and antioxidant defense. Under conditions of high energy expenditure due to environmental stress, animals prioritize defense, which carries a significant metabolic cost (Cresswell et al., 1992; Guedes et al., 2006). This reallocation of energy resources can lead to inadequate energy supply for growth and development (Beyers et al., 1999).

The larvae in this study exhibited increased energy expenditure due to the additional defensive activity of P450 detoxification and antioxidants in response to imidacloprid toxicity. Consequently, a portion of their food resources was diverted towards detoxification and antioxidant defense, compromising energy allocated for growth and development, ultimately resulting in developmental retardation. These findings suggest that imidacloprid-induced developmental retardation in bee larvae may be partly attributed to the diversion of energy resources towards detoxification and defense.