Effects of landscape variation on thermoregulation and performance in Apis mellifera honey bee colonies: Insights from mtDNA haplotypes

Authors: Alburaki, Mohamed; GARNERY, LIONEL - National Council For Scientific Research-Cnrs

Submitted to: Journal of Apicultural Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/9/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary: Our data demonstrate that honey bee colonies thrive in landscapes featuring urban components, which facilitate more efficient and optimal inner hive thermoregulation. Notably, hive temperature exhibited the most significant positive correlations, regardless of other variables, underscoring its pivotal role in ensuring colony well-being. This underscores the importance of giving due attention to hive materials and insulation rates. Such considerations can minimize the energy required for maintaining hive temperature and reduce honey consumption. Furthermore, the observed differences in thermoregulation among haplotypes, as identified in this study, offer valuable insights. They may prove useful for assigning subspecies or haplotypes to different climate regions based on their evolutionary context and historical adaptations. This knowledge can contribute to more informed and targeted beekeeping practices, promoting the health and resilience of honey bee populations in diverse environments.

Technical Abstract: In a year-long research study, we delved into the thermoregulation and performance of twenty-one honey bee colonies situated in three distinct landscape settings: 1- Urban, 2- Agricultural (AG), and 3- Non-agricultural (Non-AG) environments. All colonies, consistent in size, were equipped with sensors designed to record inner hive temperature and humidity. Additionally, colonies were placed on precision electronic scales for weight monitoring. Varroa mite infestations were documented at seven different time points throughout the experiment. Colonies were genetically analyzed for subspecies and haplotype identification using the in silico DraI mtDNA COI-COII test. Our results unveiled an overall significant (p < 0.001) weight gain (5.76 kg) in colonies located within the urban setting, in stark contrast to both AG and Non-AG locations. Notably, colonies situated in the natural refuge center (Non-AG) experienced a weight loss of -0.05 kg, signaling a lack of sustainable forage resources in such a setting. Similarly, the inner hive temperature was significantly (p < 0.001) higher in the urban area (33.65°C) with a significantly lower relative humidity (61.2 %) compared to both other locations. Among the locations, the temperature variable displayed the strongest significant correlation (p < 0.001) with a positive correlation coefficient (r = 0.95). Two distinct mtDNA haplotypes were identified: C1 and C2j, characterizing the ligustica and carnica maternal origin, respectively. These haplotypes consistently demonstrated significant differences in their thermoregulation and weight gain, irrespective of the landscape compositions. The C1 haplotype displayed significantly higher weight gain alongside lower inner hive temperature and humidity levels compared to the C2j haplotype. No differences in mite infestation were observed between the various locations or haplotypes. Our data underscores the substantial impact of landscape composition on honey bee performance. It also unveils significant variations in thermoregulation and adaptation between haplotypes, shedding light on the multifaceted relationship between environmental factors, genetics, and bee colony dynamics.