Plasticity of nutrient accumulation patterns in diapausing fall webworm pupae.

Area of Science:

• Entomology
• Insect Physiology
• Environmental Biology

Background:

• Nutrient accumulation is vital for insect diapause success, impacting survival and reproduction.
• The fall webworm (Hyphantria cunea) utilizes photoperiod to regulate diapause incidence and intensity.
• Understanding energy reserves during diapause preparation is key to insect survival strategies.

Purpose of the Study:

• To investigate the influence of photoperiod on energy reserve accumulation during diapause preparation in the fall webworm.
• To test the hypothesis that photoperiod affects nutrient storage in diapausing pupae.

Main Methods:

• Comparing body size, mass, lipid, and carbohydrate content in pupae reared under different photoperiods.
• Assessing the efficiency of food conversion in larvae destined for diapause under varying photoperiods.
• Measuring lipase, amylase, and protease activities in the midgut of larvae.

Main Results:

• Pupae from short photoperiods exhibited significantly greater body mass, lipid, and carbohydrate content.
• Short-photoperiod larvae showed enhanced efficiency in converting ingested and digested food.
• Increased lipase and amylase activity was observed in short-photoperiod larvae, while protein and protease levels remained unchanged.

Conclusions:

• Fall webworm energy reserve accumulation is plastic and photoperiod-dependent.
• Short-photoperiod exposure enhances feeding efficiency and promotes lipid/carbohydrate storage via increased digestive enzyme activity.
• These adaptations improve the likelihood of successful diapause and subsequent survival.