Abstract
Ectothermic organisms including insects are highly vulnerable to climate warming which not only influences their biology, ecology and physiology but also affects their symbiotic gut microbiota. This study determined the impact of ambient (control) and simulated warmer (heating) climatic conditions on the microclimate of brood nest and gut bacterial abundance of two
subspecies i.e.
and
. For both subspecies, brood nest temperature and relative humidity under the heating treatment were significantly different (p≤0.001) than those under the control treatment. Quantitative PCR data revealed that the abundance of gut bacteria (16
RNA gene copy numbers) of
and
larvae was significantly higher (P≤0.05), 1.73 and 5.32 fold higher respectively, during the heating treatment than those in control conditions. Although gut bacterial abundance of
(1.67 × 10
copies g
fw) and
(1.7 × 10
copies g
fw) larvae was similar during the control treatment,
larvae exhibited three times greater gut bacterial abundance than
during the heating treatment. Similarly, adult
bees harboured significantly greater bacterial abundance during the heating treatment than control. These findings elucidate that climate warming may significantly affect the honeybee colony microclimate and their gut bacterial abundance. However, further studies are needed to better understand how gut microbial community may influence the learning, physiological and behavioural mechanisms of the host bees in a climate warming scenario.