MSc

The present investigation entitled “Origin and composition of stingless bee
propolis” was conducted at the Department of Agricultural Entomology, College of
Agriculture, Vellayani during 2020-2022. The objective of the study was to assess the
resin-foraging behaviour of stingless bees, the origin of the resin, and the
characterization of bee propolis.
Four locations viz., AICRP on Honey Bees and Pollinators, Vellayani, and
apiaries in Nedumangad, Mariapuram, and Navaikulam were selected for the study.
Resin sources, foraging rate, physical characteristics, and major components of propolis
were studied.
The trees and plants were observed within up to a 100m radius of the bee hive
for identifying the resin source. Plants identified were Mango tree (Mangifera indica
L.), Jack tree (Artocarpus heterophyllus Lam.), Breadfruit tree (Artocarpus altilis
Parkinson), Cashew tree (Anacardium occidentale L.), Cambodge tree (Garcinia
cambogia Syn.), False mangosteen (Garcinia xanthochymus Hook.), Monkey puzzle
tree (Araucaria araucana Molina).
Based on the resin flow and wounds present, plants were grouped into 4 grades
from 1-4. The number of bees visiting the wound was also counted. M. indica (4) and
G. cambogia (3) were recorded with maximum stingless bees foraging per day. A.
araucana and G. xanthochymus came under grade 2 with minimum stingless bees
foraging per day.
Resin foraging activity was found high from 0900h to 1600h in all the locations
throughout the observation. Peak foraging activity was noticed from 1100h to 1200h at
Vellayani, Mariapuram, and Nedumangad, Navaikulam. There was no significant
correlation between weather parameters and resin foraging rate when correlation studies
were conducted.
Propolis from all the locations possess pleasant aromatic smells and was sticky
in texture at normal temperatures and hard at cold temperatures. The colour of propolis
from Vellayani and Navaikulam was moderate brown. It was dark grayish-reddish
brown and moderate olive brown in Nedumangad and Mariapuram respectively.
LC-HRMS and GC-HRMS analysis revealed that the main chemical classes
present in the propolis were acids, fatty acids, steroids, alcohols, amines, amino acids,
flavonoids, terpenoids, chalcones, aldehydes, ketones, benzene, coumarin, pterocarpan,
ether, and ester. The predominant components identified in the propolis of Vellayani
and Nedumangad were 20S, 24S-dihydroxy dammer-25-en-3-one, whereas it was
Glycyrrhizic acid in Mariapuram and Navaikulam. The various components found
common throughout the locations were syringic acid, and ellagic acid (acids), punicic
acid, 9,10-dihydroxystearic acid, and phloionolic acid (steroids and fatty acids),
thevetiaflavone, luteolin, and quercetin (flavonoids), octadecanamine and oleamide
(amines), ursolic acid and oleanolic acid (terpenoids), 5-[(z)-pentadec-8-enyl] benzene1,3-diol (alcohols), dihydrocordoin and orotinichalcone (chalcones).
Thus, this study identified different botanical resin sources and found M.
indica and G. cambogia with maximum stingless bees foraging. High foraging activity
was observed from 0900h to 1600h in all the locations throughout the year. Several
components were identified with functional groups like acids, fatty acids, steroids,
alcohols, flavonoids, terpenoids, etc. from the propolis when the chemical
characterization studies were carried out.