Adapted dandelions trade dispersal for germination upon root herbivore attack

Area of Science:

• Plant ecology
• Evolutionary biology
• Insect-plant interactions

Background:

• Seed dispersal is a key plant strategy for escaping unfavorable conditions.
• The role of seed dispersal in escaping insect herbivores is not fully understood.
• Dandelions (Taraxacum officinale agg.) offer a model system to study plant responses to herbivory.

Purpose of the Study:

• To investigate how root herbivore attack influences seed dispersal in different dandelion populations.
• To determine if plant adaptation to herbivory affects the response of seed dispersal.
• To explore the trade-offs associated with induced changes in seed dispersal.

Main Methods:

• A manipulative field experiment was conducted using dandelion populations with varying evolutionary histories of root herbivory.
• Root herbivore (Melolontha melolontha larvae) attack was applied to assess its impact on seed traits.
• Seed weight, dispersal potential, germination rate, and vegetative growth parameters were analyzed.

Main Results:

• Root herbivore attack increased seed dispersal potential by reducing seed weight in populations previously exposed to high herbivore pressure.
• This effect was not observed in populations with low prior herbivore pressure.
• The enhanced dispersal potential was linked to a reduced germination rate, irrespective of plant cytotype (diploid vs. triploid).

Conclusions:

• Root herbivory can select for an induced increase in seed dispersal ability in adapted plant populations.
• Induced seed dispersal may serve as a strategy for plants to escape root herbivores.
• Dandelions may trade-off seed establishment for enhanced dispersal when facing herbivore attack.