Body mass and mate choice in bumblebees (Bombus terrestris) under climate heating

Area of Science:

• Ecology
• Evolutionary Biology
• Climate Change Biology

Background:

• Climate warming affects bumblebee populations, reducing body size and pollination efficiency.
• The impact of reduced body mass on bumblebee mating behavior and subsequent generation viability is not well understood.

Purpose of the Study:

• Investigate how elevated temperatures influence male-male competition and queen mate choice in bumblebees (Bombus terrestris).
• Determine the effects of body size on mating success and sperm transfer under varying temperature conditions.

Main Methods:

• Conducted mating experiments with Bombus terrestris at optimal (23°C) and elevated (32°C) temperatures.
• Assessed mating rates, mating duration, sperm transfer, and queen survival based on body weight and temperature.

Main Results:

• Larger males consistently achieved higher mating rates and transferred more sperm.
• Male preference shifted towards larger queens at elevated temperatures (32°C).
• Queen survival post-hibernation was positively correlated with pre-hibernation body weight.

Conclusions:

• Elevated temperatures alter bumblebee mating preferences, with males favoring larger queens.
• Mate choice dynamics under warming conditions significantly influence the viability of subsequent bumblebee generations.