Maes Patrick W, Floyd Amy S, Mott Brendon M, Anderson Kirk E
Graduate Interdisciplinary Program in Entomology and Insect Science, University of Arizona, P.O. Box 210036, Tucson, AZ 85721, USA.
USDA-ARS Carl Hayden Bee Research Center, 2000 East Allen Road, Tucson, AZ 85719, USA.
Insects. 2021 Mar 5;12(3):224. doi: 10.3390/insects12030224.
Honey bee overwintering health is essential to meet the demands of spring pollination. Managed honey bee colonies are overwintered in a variety of climates, and increasing rates of winter colony loss have prompted investigations into overwintering management, including indoor climate controlled overwintering. Central to colony health, the worker hindgut gut microbiota has been largely ignored in this context. We sequenced the hindgut microbiota of overwintering workers from both a warm southern climate and controlled indoor cold climate. Congruently, we sampled a cohort of known chronological age to estimate worker longevity in southern climates, and assess age-associated changes in the core hindgut microbiota. We found that worker longevity over winter in southern climates was much lower than that recorded for northern climates. Workers showed decreased bacterial and fungal load with age, but the relative structure of the core hindgut microbiome remained stable. Compared to cold indoor wintering, collective microbiota changes in the southern outdoor climate suggest compromised host physiology. Fungal abundance increased by two orders of magnitude in southern climate hindguts and was positively correlated with non-core, likely opportunistic bacteria. Our results contribute to understanding overwintering honey bee biology and microbial ecology and provide insight into overwintering strategies.
蜜蜂越冬健康对于满足春季授粉需求至关重要。人工饲养的蜂群在各种气候条件下越冬，而冬季蜂群损失率的上升促使人们对越冬管理展开调查，包括室内气候控制越冬。蜂群健康的核心在于工蜂后肠微生物群，但在这方面它在很大程度上被忽视了。我们对来自温暖的南方气候地区和可控室内寒冷气候环境下的越冬工蜂后肠微生物群进行了测序。同时，我们对一组已知年龄顺序的工蜂进行采样，以估计南方气候地区工蜂的寿命，并评估核心后肠微生物群与年龄相关的变化。我们发现，南方气候地区工蜂的越冬寿命远低于北方气候地区记录的寿命。随着年龄增长，工蜂的细菌和真菌负荷降低，但核心后肠微生物组的相对结构保持稳定。与寒冷的室内越冬相比，南方室外气候下微生物群的总体变化表明宿主生理机能受损。在南方气候地区的后肠中，真菌丰度增加了两个数量级，并且与非核心、可能是机会性细菌呈正相关。我们的研究结果有助于理解蜜蜂越冬生物学和微生物生态学，并为越冬策略提供见解。
