1. Highlight on the complex composition of
Vespa velutina nigrithorax venom gland
Journées GDR MediatEC 2021
Berville L, Lucas C, Haouzi M, Khalil A, Gévar J, Bagnères A-G, Darrouzet E

2. CONTEXT
INVASIVE SPECIES:
New constituent of ecosystems
Permanently modifying the distribution and
diversity of natural life
CONSIDERABLE DECLINE IN POLLINATORS:
land-use, urbanisation, which result in the loss and degradation of natural habitats
disappearance of diverse flora, reducing food and nesting resources
PESTICIDES:
directly (insecticides and fungicides)
and indirectly (herbicides)
CHANGING CLIMATE :
SOCIAL INSECTS:
Considered to be the most successful
invaders
 Excellent dispersal and
competitive abilities
 Effective defenses & High
reproduction rates
 diets ranges & broad habitat

3. Vespa velutina nigrithorax
10 years
Transport Introduction
•Reproduce
•Spread
Establishment
Dominate
community

4. IMPACTS
• Direct economic impacts
• large impacts to honeybee
populations
=> honey production
• Indirect economic impacts
• loss of ecosystem services
• Direct environmental impacts
• Predation on severals
insects and arthropod taxa
• Risk for human health

5. GOALS
• The hornets persistence has inspired the
development of control methods
• Induce significant ecological impacts
=> lack of species-specificity
• Hornet NestTreatment
• Insecticide
CURRENT PRACTICE
News species-specific trapping systems based on pheromones are
ongoing developments

6. CURRENT PRACTICE
• Chemical signals, like
pheromones, often trigger
different behaviors like :
• Recruitment,
• Dispersal,
• Aggressiveness,
• Aggregation
➢ Alarm pheromones are key importance
o Multi-components blends
o Highly volatile
➢ Venom glands are often the primary source (wasps & hornet)
2 studies presented the evidence of the alarm pheromone in both
V. velutina auraria & V. v. nigrithorax
(Cheng et al. 2017 & Thiery et al. 2018)

7. Gynes
Foundresses
Queens
Workers
Stressed workers
May /
June
June /
August
May /
August
May /
August
Our goal was to clarify the composition of the
invasive species’ alarm pheromone and to assess
differences in chemical profiles among queens,
foundresses, pre wintering gynes, and workers.

8. Pre wintering
gynes
Foundresses
Queens
Workers
Stressed workers
GOALS : composition of the volatile molecules produced by females
May /
August

9. W
G
F
Q
a. 5 venom sacs were pooled
b. 1 ml of heptane
c. 2 µL gland’s extract were analyzed
First Experiment : composition of the volatile molecules produced by females
x15
x8
x6
x6

10. 38 compounds with chain lenghs from 10 to 16 carbons
26 peaks presented an average relative area bigger than 0,5%
First Experiment : composition of the volatile molecules produced by females
Workers
PW gynes
Foundresses
Queens

11. 26
COMPOUNDS
• Gynes & foundresses
• 25 : Queens
• 23 : Workers
11 ketones
8 Esters
3 Alcohols
3 unknowns
RESULTS
28 %
of the total blend
• 4,8 DiMe-7-nonen-2-one
First Experiment : composition of the volatile molecules produced by females
10 news
molecules
• Between C10 and C16
Workers
PW gynes
Foundresses
Queens

12. 26
COMPOUNDS
• Gynes & foundresses
• 25 : Queens
• 23 : Workers
RESULTS
Queens
Workers PW gynes
Foundresses
P1Q
P2Q
P3Q
P4Q
P5Q
P6Q
P1F
P3F
P2F
P4F
P5F
P6F
P1O
P2O
P3O
P4O P5O
P6O
P7O
P8O
P9O
P10O
P11O
P12O
P13O
P14O
P15O
P1G
P2G
P7G
P6G
P5G
P4G
P3G
-4 -2 0 2 4
Factor 1: 38,82%
-4
-3
-2
-1
0
1
2
3
4
Factor
2:
19,55%
P1Q
P2Q
P3Q
P4Q
P5Q
P6Q
P1F
P3F
P2F
P4F
P5F
P6F
P1O
P2O
P3O
P4O P5O
P6O
P7O
P8O
P9O
P10O
P11O
P12O
P13O
P14O
P15O
P1G
P2G
P7G
P6G
P5G
P4G
P3G
a
b
c
d
e
f
g
h
i
j
k
l
m
n
o
p
q
r
s
t
u
v
w
x
y
z
-1,0 -0,5 0,0 0,5 1,0
-1,0
-0,5
0,0
0,5
1,0
a
b
c
d
e
f
g
h
i
j
k
l
m
n
o
p
q
r
s
t
u
v
w
x
y
z
First Experiment : composition of the volatile molecules produced by females
The ellipses indicate the 95% confidence limit of the data.
GROUPS
3
• Workers and Gynes : NS

13. Gynes
Foundresses
Queens
Workers
Stressed
workers &
gynes
GOALS : composition of the volatile molecules produced by females

14. a. 4 living workers or 4 pre wintering gynes
b. 350mL glass vial
c. Stressed or Injured
d. Red SPME Fiber : 40 minutes
Second Experiment : composition of the volatile molecules produced by stressed individuals
Fiber
x8 x4

15. 13
COMPOUNDS
GROUP
one
• Gynes & Workers
36 %
of the total blend
• Workers and Gynes : NS
• FH and SH : NS
• 4,8 DiMe-7-nonen-2-one
PCA of the PDMS-SPME analysis of workers and gynes that were
stressed (SH, G n=4; W n=8) or frightened (FH, G n=4; W n=8).
The ellipses indicate the 95% confidence limit of the data.
Second Experiment : composition of the volatile molecules produced by stressed individuals
RESULTS

16. CONCLUSIONS
Marked separation among foundresses, queens and pre wintering gynes.
➢ This result indicates that the chemical signature of a female’s venom gland changes across life-
history stages
Gynes’ profiles are closer to workers
➢ Gynes’ profiles later shift.
Contrary to previous studies, the major compound observed, in
this study, in all castes, was 4,8-diMe-7-nonen-2-one (21–28 %)
No difference in Workers & Gynes’ profiles – A live individuals (SPME)
➢ No difference in SH &FH’ profiles
➢ 10 news molecules described

17. Somes molecules will be tested on bees. Bees
may detect some components in hornet
alarm pheromone and thus modified their
behavior
FIELD TRIALS
Cheng et al. 2017
Thiery et al. 2018
Berville et al. 2023
PHEROMONE IDENTIFICATION
IDENTIFING THE LAST MAJOR MOLECULE
Assess the potential effect of
each major molecule.
One by one, and as a blend
PROSPECTS
PHEROMONE-BASED
TRAP OR REPELLENT
PHEROMONE TRIALS (lab)

18. Merci