Leaf herbivory by insects during summer reduces overwinter browsing by moose

Area of Science:

• Ecology
• Animal Behavior
• Plant-Insect Interactions

Background:

• Herbivore damage to plants can alter resource availability for subsequent consumers.
• Indirect interactions between insect herbivores and mammalian browsers are not well understood.
• This study examined insect impacts on willow plants and subsequent moose browsing in Alaska.

Purpose of the Study:

• To investigate the indirect effects of insect herbivory on willow leaves.
• To assess the impact on moose winter browse consumption and plant production.
• To understand cascading effects in the Alaskan boreal forest food web.

Main Methods:

• Experimentally reduced insect damage on Salix interior using insecticide.
• Measured stem biomass and quality (nitrogen, tannins) of willow plants.
• Monitored moose browse consumption of treated and control plants.

Main Results:

• Insecticide treatment reduced leaf damage by Micrurapteryx salicifoliella.
• Reduced insect damage led to increased stem biomass production.
• Moose consumed a greater proportion of woody tissue from plants with less insect damage.

Conclusions:

• Insect herbivory significantly influences plant stem production.
• Moderate insect leaf damage can have substantial indirect effects on large mammalian herbivores.
• These findings highlight the importance of insect-plant interactions in shaping herbivore foraging behavior.