Leaf miner-induced changes in leaf transmittance cause variations in insect respiration rates

Area of Science:

• Ecology
• Entomology
• Plant-insect interactions

Background:

• Herbivore feeding can alter the microclimate of host plants.
• The specific impact of leaf miner feeding on leaf optical properties and subsequent effects on the herbivore's physiology are not well understood.

Purpose of the Study:

• To investigate how the feeding activity of the leaf miner Phyllonorycter blancardella F. modifies leaf transmittance.
• To determine the effects of these modifications on the herbivore's body temperature and respiration rate under varying radiation levels.

Main Methods:

• Spectrometry was used to measure changes in leaf transmittance properties.
• An infrared gas analyzer measured the herbivore's body temperature and respiration rate under controlled radiation levels.
• Experiments were conducted with leaf miners feeding on host plants, creating 'feeding windows'.

Main Results:

• Leaf miner feeding creates 'feeding windows' that significantly increase radiation transmission within the mine.
• Herbivore body temperature and respiration rate increase with radiation levels when positioned below feeding windows.
• In contrast, body temperature and respiration rate showed only slight increases under intact leaf tissues with low radiation transmission.
• CO(2) release was five-fold higher in larvae below feeding windows at high radiation compared to dark conditions.

Conclusions:

• Leaf miner-induced changes in leaf transmittance create a heterogeneous light environment within the mine.
• The leaf miner can behaviorally thermoregulate by utilizing this heterogeneous environment.
• Herbivory-induced physical changes significantly impact insect metabolism, independent of nutritional status.