Nosema ceranae infection intensity highly correlates with temperature

Area of Science:

• Veterinary Entomology
• Apiculture Science
• Microbial Pathogenesis

Background:

• Nosema ceranae, a microsporidian, emerged in honey bees (Apis mellifera) in Taiwan in 2005.
• It is a significant global concern for apiculture.
• Previous studies on Nosema apis reported distinct seasonal infection patterns.

Purpose of the Study:

• To investigate the seasonal infection dynamics of Nosema ceranae in Taiwan.
• To compare N. ceranae infection patterns with historical N. apis data.
• To determine the relationship between temperature and N. ceranae infection intensity.

Main Methods:

• Field monitoring of honey bee apiaries in Taiwan.
• Microscopic quantification of Nosema ceranae spores.
• Statistical analysis of pathogen load in relation to environmental factors, particularly temperature.

Main Results:

• Nosema ceranae exhibited a single annual infection peak during winter months in Taiwan.
• This contrasts with the spring and fall peaks previously reported for Nosema apis.
• A significant negative correlation was found between N. ceranae pathogen load and ambient temperature, with peak spore counts around 15°C.

Conclusions:

• Nosema ceranae's distinct seasonal pattern and earlier infection intensity may contribute to its displacement of Nosema apis.
• The findings provide a temperature-dependent model for N. ceranae infections, most applicable to subtropical and tropical climates.
• Understanding these dynamics is crucial for managing honey bee health and apiculture sustainability.