• Insects control gas exchange by opening and closing peripheral spiracular valves
  
• By closing all valves, the entire organism can be sealed hermetically against the environment, providing a temporary autonomic breathing space:
  • Oxygen (O₂) is mainly stored in the tracheal system and is used for aerobic metabolism.
  • Carbon dioxide (CO₂) is the metabolic waste product and is mainly stored in hemolymph and tissue.
    
• The amount of gas that can be stored and the rate of withdrawal or accumulation of the gases in the reservoirs determines the frequency, duration, and magnitude of spiracular opening.
  
• The oscillating processes of storing and exchanging gases controlled by spiracular activity results in cyclic gas exchange patterns and - in its most striking form - in Discontinuous Gas Exchange Cycles (DGE or DGC).

In my studies, I focused on many unique features of insect respiration:

Spiracular control valves

Mechanical function
Regulatory control processes

Tracheal system

Morphology

Dimensions (volume, cross sectional area)
Structure (branching, anastomoses, air sacks)

Adaptations to metabolic demands
Adaptations to environmental constraints
Gas exchange dynamics (ventilation, diffusion)

Hemolymph

Volume
Contents (organic and inorganic ions)
Role as reservoir for respiratory gases
Role as buffer for CO₂ and other metabolic end products

Respiratory patterns

Classification (continuous, cyclic, discontinuous, ventilation)
Occurrence (phylogeny, habitat)
Metabolism

CO₂ release
O₂ consumption
Respiratory and cuticular water loss

Modulation as response to

Metabolic demands
Adaptations to environmental conditions

Varied gas concentrations
Temperature
Relative humidity and water availability

Future projects will include:

Interactions between central nervous system and spiracular valves during DGC.

Effects of hypoxia and hyperoxia on development and physiology of aquatic gill-breathing apneustic (without any spiracle) insect larvae.

Oxygen supply in large insects with long appendages (Harlequin Beetle, Giant Stick Insect).

Modeling convective-diffusive gas transport in the tracheal system.