Dear Zong-Xin,

I would like to make the starter for this intersing question by listing potential souces of smell in honey. It is possible that flowers secrete a nectar that includes volatiles. It is also likely that floral volatiles are soleved in nectar and thus make the nectar smelly. Bactera and fungi in the nectar may produce volatile substances. Bees that take up the nectar, carry it in the honey stomach and regurgitate it likely add volatile substance, but may also change volatiles. Contamination of nectar with volatiles from the air, from pollen and from flower visitors may add to the scent bouquet of nectar and thus impact the honey scent. Would be intersting to know what are the most important sources of honey scent.

Klaus

Dear Dr. Ren,

This is an interesting question. I think the smell come from the fermented mixed pollen and nectar.

Hai-Dong

Thanks Dr. Lunau for summary the possible reasons for smell of honey. It did interest to understand the links among flower (nectar and/or pollen), insect nectar stomach, and their microbiota. 

The smell and taste of the honey depends mainly on its NECTAR source, and consequently they depend mainly on the chemical composition of the plants that offer the nectar. These chemicals give the nectar and afterwards the honey, its distinctive characteristics.

I agree with Dr. El Ghazali's answer. The distinctive characteristics of the nectar give honey a specific smell.