Fig. 5.

Fig. 5.

Proposed model illustrating the initial adaptation of the HPI axis following ELC. Prolonged early-life activation of the HPI axis, induced by increased environmental challenge, diminishes the NPO's capacity to influence downstream HPI axis activity. Baseline conditions show enhanced cortisol inactivation, which can persist upon stress onset. There is an increase in cortisol synthesis capacity and elevated levels of stress modulators. These adaptations enhance the larva's capability to regulate GC levels, preventing excess cortisol while facilitating its production in response to familiar stress.