Effects of simazine and food deprivation chronic stress on energy allocation among the costly physiological processes of male lizards (Eremias argus).

The residue of simazine herbicide in the environment is known as one of pollutant stress for lizards by crippling its fitness on direct toxic effects and indirect food shortage via the food chain effects. Both stressors were considered in our experiment in the simazine exposure and food availability to lizards (Eremias argus). The results revealed that starvation significantly reduced the lizard's energy reserve and native immune function, while the accumulation of simazine in the liver was significantly increased. Simazine caused oxidative stress in the liver of lizards, but oxidative damage only occurred in the starved lizards. Simazine also changed the energy reserves, native immune function and detoxification of well-fed lizards, while the starved lizards showed different sensitivity to simazine. Simazine or starvation treatment independently activated the lizard HPA axis, but co-treatment caused the HPA axis inhibition. Besides, according to the variations on amino acid neurotransmitters, corticosterone hormone and thermoregulatory behavior, we inferred that lizards in threatens take the appropriate strategy on energy investment and allocation through neural, endocrine and behavioral pathways to maximize benefits in dilemma. Energy allocation was necessary, while suppression on any physiological process comes at a cost that is detrimental to long-term individual fitness.