Bombus terrestris Prefer Mixed-Pollen Diets for a Better Colony Performance: A Laboratory Study.

Area of Science:

• Entomology
• Pollination Ecology
• Animal Nutrition

Background:

• Pollen provides essential proteins and lipids for bumblebees, crucial for colony development.
• Nutritional variations in pollen from different plant sources can significantly influence bumblebee colony success.

Purpose of the Study:

• To investigate the foraging preferences of Bombus terrestris for four distinct pollen types: oilseed rape, wild apricot, sunflower, and buckwheat.
• To assess the impact of different pollen diets on bumblebee colony development under controlled laboratory conditions.

Main Methods:

• Laboratory-based study evaluating Bombus terrestris foraging choices among four pollen species.
• Analysis of colony development metrics (offspring number, body size, colony weight) based on controlled pollen diets.
• Chemical analysis of pollen nutritional content, specifically protein and lipid levels, and calculation of protein-lipid ratios.

Main Results:

• Bombus terrestris exhibited varied pollen preferences, with wild apricot being the most preferred and sunflower the least.
• Colonies fed a mixed four-pollen diet (protein-lipid ratio 4.55-4.86) showed superior development.
• Buckwheat and sunflower pollen diets resulted in significantly fewer workers and inhibited reproductive offspring (queens and males); wild apricot pollen was richest in protein (23.9 g/100 g), and oilseed rape in lipids (6.7 g/100 g).

Conclusions:

• Bombus terrestris demonstrates specific feeding preferences for different pollen types and mixed diets.
• Pollen diet composition directly influences bumblebee colony development, affecting reproductive success and overall colony health.
• Findings offer critical data for developing optimized nutritional strategies for bumblebee populations.