This document discusses the role of the vitellogenin (vg) and vitellogenin-like (vg-like) genes in honey bee longevity and immunity. Vg is known to affect longevity, immunity, and division of labor in bees. Recently, three vg-like genes (A, B, C) were discovered but their roles are unknown. The study examined the expression of these genes in bees under oxidative stress and overwintering bees. The results showed that vg and vg-like-A were upregulated under oxidative stress and highly expressed in overwintering bees, suggesting they promote longevity. Vg-like-B also upregulated under oxidative stress, while vg-like-C showed no response.

1. Vitellogenin and vitellogenin­like
genes in the honey bee
Background
The honey bee is ecologically important and a hot topic because of its decline
worldwide. The life span of honey bees varies tremendously: the queen lives for
several years, a drone for one summer and the workers for 4-6 weeks, but, in the
wintertime, workers live up to 10 months, depending on the need.
A gene called vitellogenin (vg) could be one reason for this variation. Vg is a
pleiotropic gene which is present in all egg-laying animals. Besides egg-yolk
formation, it also affects e.g. longevity, immunity and division of labour in the honey
bee. Vg can act as an antioxidant, and therefore shield a bee from oxidative
stress, which causes ageing. Recently, three vitellogenin-like genes have been
found, but their role is not discovered. They are named vg-like-A, vg-like-B and vg-
like-C.
Study questions
i. Are vg and vg-like genes expressed when the bee is exposed to oxidative stress?
ii. Is Vg protein removed from the bee’s hemolymph after shielding her?
iii. Are vg and vg-like genes expressed in the overwintering bees?
Materials and methods
i. Gene expression: 150 nurse bees from 5 colonies
ii. Protein electrophoresis: 24 nurse bees from one colony
iii. Gene expression: 30 winter bees from 3 colonies
Treatment groups
Acknowledgements
This project was supported by Academy of Finland Honey Bee Health and Immunity project
number 265971, by Centre of Excellence in Biological Interactions, and by the Finnish
Beekeepers' Association
Conclusions and discussion
i. Vg and vg-like genes are differentially expressed
under oxidative stress
● Vg-like-A seems to be an immunity gene, which
upregulates in stressful events - like vg
● Injection alone caused strong upregulation of vg
and vg-like-A
ii. Our protein electrophoresis results were
inconclusive about the change in Vg protein
● Problems in the method?
● perhaps Vg first goes up in response to injection,
and then straight down after confronting stress?
iii. High expression of vg and vg-like-A in overwintering
bees suggest that these genes could have a role in
promoting longevity
Nurse bees on brood comb
A forager
Taina Stark1,2
Siiri Fuchs2
, Dimitri Stucki2
, Dalial Freitak2
, Heikki Hokkanen1
, Heli Salmela2
, Liselotte Sundström2
1
University of Helsinki, Department of Agricultural Sciences, 2
University of Helsinki, Department of Biosciences, Centre of Excellence in Biological Interactions
Contact: taina.stark@helsinki.fi
Injected with Paraquat, which induces
oxidative stress
Injected with physiological saline
Test Sham Control
No injections
Results
Inflammation by
injection (both
sham and
Paraquat) had a
surprisingly strong
upregulating
effect on vg and
vg-like-A
expression
Vg-like-B
upregulated when
injected with
Paraquat, and vg-
like-C showed no
significant
response
Winter bees
expressed high
amounts of vg
and vg-like-A
Gene expression:
Protein electrophoresis:
● No differences were found between treatments when
measuring Vg protein from fat body and hemolymph
samples. Comparing to gene expression results: a
paradox?
v