How generalist herbivores exploit belowground plant diversity in temperate grasslands

Area of Science:

• Ecology
• Entomology
• Plant Science

Background:

• Belowground herbivores significantly influence plant communities and ecosystem processes.
• External root-chewing insects, like Agriotes click beetle larvae, are key players, but their field feeding behavior is poorly understood.
• Understanding this feeding behavior is crucial for comprehending their ecological impact.

Purpose of the Study:

• To investigate the feeding behavior of Agriotes click beetle larvae in temperate grasslands.
• To determine seasonal feeding activity patterns and plant taxa preferences.
• To assess the influence of herbivore species and larval instar on food choices.

Main Methods:

• Diagnostic multiplex PCR was used to analyze the gut contents of Agriotes larvae.
• Seasonal sampling was conducted throughout the vegetation period.
• Dietary data were analyzed for feeding activity, plant preferences, and species/instar effects.

Main Results:

• Larvae were active feeders throughout the entire vegetation period, indicating continuous feeding pressure.
• Feeding was selective, with Plantaginaceae and Asteraceae preferred, and Apiaceae avoided.
• Poaceae showed intermediate preference, contrary to expectations. Food preferences shifted seasonally.
• Differences in diet based on Agriotes species and larval instar were minimal.

Conclusions:

• Grassland plants face constant belowground herbivory pressure from Agriotes larvae.
• Plant identity is the primary driver of wireworm food choice, with seasonal fluctuations.
• The findings highlight the need to consider plant-specific traits and seasonal dynamics in soil herbivore-plant interaction studies.