Predispersal seed predation in Bartsia alpina

Area of Science:

• Ecology
• Entomology
• Botany

Background:

• Bartsia alpina, an arctic-alpine plant, experiences significant seed predation.
• Two specialist insect larvae, Aethes deutschiana and Gimnomera dorsata, are identified as key predators.
• The parasitoid Scambus brevicorais attacks these seed predators.

Purpose of the Study:

• To investigate seed predation levels and patterns in Bartsia alpina.
• To identify the primary insect predators and their host specificity.
• To understand the impact of seed predation on the plant's mating system.

Main Methods:

• Field observations and data collection over several years (1985-1988).
• Assessment of predation levels in relation to inflorescence size and position.
• Analysis of seed predation impact on outcrossing rates.

Main Results:

• Predation pressure was high and relatively constant, doubling in 1988.
• Aethes deutschiana, a tortricid moth, is a newly identified specialist predator of B. alpina.
• Seed predation was higher in large inflorescences and concentrated in the middle sections, increasing the proportion of outcrossed seeds.

Conclusions:

• Seed predation by insects significantly influences the mating system of Bartsia alpina, favoring outcrossing.
• The study highlights complex interactions within the plant-insect food web, including host-parasitoid relationships.
• Understanding these dynamics is crucial for conservation and ecological studies of arctic-alpine ecosystems.