The Physiological Cost of Being Hot: High Thermal Stress and Disturbance Decrease Energy Reserves in Dragonflies in...

Area of Science:

• Ecology
• Environmental Science
• Insect Physiology

Background:

• Anthropogenic disturbance alters climate, raising temperatures.
• Elevated temperatures cause thermal stress in insects, depleting energy reserves.
• Dragonflies are sensitive to thermal stress due to high metabolic demands.

Purpose of the Study:

• Evaluate thermal stress in dragonflies across preserved and disturbed tropical dry forest sites.
• Compare insect energetic condition (lipid, protein, thoracic mass) between habitats.
• Investigate the relationship between thermal stress, habitat type, and insect energy reserves.

Main Methods:

• Assessed thermal stress in 16 dragonfly species across two sampling periods (2019, 2022).
• Collected data in preserved and disturbed tropical dry forest sites in western Mexico.
• Quantified lipid and protein content and thoracic mass for seven abundant species.

Main Results:

• Dragonflies in preserved sites showed higher thermal stress at lower temperatures, decreasing as temperatures rose.
• Disturbed sites exhibited consistent thermal stress across temperature gradients.
• Thermal stress correlated with lower lipid and protein content; disturbed sites had reduced energy reserves.
• A positive relationship was observed between ambient temperature and protein content.
• Thoracic mass increased with thermal stress in preserved sites at high mean temperatures.

Conclusions:

• Disturbed habitats compromise dragonfly energetic condition, potentially impacting fitness.
• Species can persist in disturbed areas but with reduced physiological performance.
• Habitat preservation is vital for maintaining insect biodiversity and ecosystem function.