C HEMICAL AND PHYSICAL FACTORS INVOLVED IN THE AGGREGATION BEHAVIOUR OF H ARMONIA AXYRIDIS P ALLAS...

CHEMICAL AND PHYSICAL FACTORS INVOLVED IN THE AGGREGATION

BEHAVIOUR OF HARMONIA AXYRIDIS PALLAS

Department of Functional and Evolutionary Entomology

Durieux D., Fischer C., Deneubourg J.L., Brostaux Y., Lognay G. , Vandereycken A., Joie E., Haubruge E., Verheggen F. J.

CONTEXT

AGGREGATION

annoyance from their number

tainting walls and curtains

allergic reactions

asthma

urticariarhinitis

cough,…conjunctivitis

ISCE, Durieux D. et al.

CONTEXT

Migratory flight Macrosite choice

Microsite choice

Physical factors

Chemical factors

?


CHEMICAL FACTORS : PREVIOUS STUDIES

Volatile compounds Pyrazines (al Abassi et al., 1998)

(-)- β-caryophylleneEmission by H. axyridis in wintering conditions(Brown et al., 2006)

the seven spotted ladybird, Coccinella septempuctata

Attractive and aggregative potential (Verheggen et al., 2007)


CHEMICAL FACTORS

1

6

2 3

4 5

Multi-choice experiment

Implication of long chain hydrocarbons in the aggregation behavior of Harmonia axyridis (PALLAS) (Coleoptera: Coccinellidae) Durieux D., Fischer C., Deneubourg J.L., Lognay G., Vandereycken A., Joie E., Haubruge E. and Verheggen F.J. (under review)


CHEMICAL FACTORS

1

6

2 3

4 5

After 8 hours:

Test χ² (chi-square of goodness-of-fit test) : P < 0,001



0

10

20

30

40

50

60

1 2 3 4 5 6

mea

n pe

rcen

tage

of H

. axy

ridis

Area of the multi-choice set-up

***


CHEMICAL FACTORS

1

6

2 3

4 5




hexane

CHEMICAL FACTORS

1

6

2 3

4 5

After 8 hours:

Test χ² (chi-square of goodness-of-fit test) : P < 0,001



0

5

10

15

20

25

30

35

40

45

1 2 3 4 5 6M

ean

perc

enta

ge o

f H. a

xyrid

isArea of the multi-choice set-up

***

The chemical blend ensures the cohesion of the aggregate


CHEMICAL FACTORS

9

Test χ² (chi-square of goodness-of-fit test) : P = 0.024 for females and P < 0.001 for males


Y-olfactometer


0

10

20

30

40

50

60

70

80

90

100

males females

Perc

enta

ge o

f lad

ybird

s ha

ving

ch

osen

eac

h ar

m

*** *

Theoretical

distribution

Study of a potential trail

CHEMICAL FACTORS

10

Test χ² (chi-square of goodness-of-fit test) : P = 0.001 for females and P = 0.002 for males


0

10

20

30

40

50

60

70

80

90

100

males females

Perc

enta

ge o

f lad

ybird

s ha

ving

ch

osen

eac

h ar

m

** **

Theoretical

distribution

Y-olfactometer

The chemical blend leads congeners towards the aggregate


Hexane

CHEMICAL FACTORS

11

Identification of compounds by GC-MS analyses

1 : heneicosane 10 : heptacosane2 : docosane 11 : nonacosadiène3 : tricosane 12 : nonacos-9-ène4 : tétracosane 13 : nonacosane5 : pentacos-9-ène 14 : hentriacontadiène6 : pentacosane 15: hentriacontadiène7 : hexacosane 16 : hentriacont-9-ène8 : heptacosadiène 17 : hentriacontane9 : heptacos-9-ène

Identified compounds

Saturated hydrocarbonsUnsaturated hydrocarbons – one double bondUnsaturated hydrocarbons – two double bonds

Aggregation blendTrail blend

Identification of the compounds used by the multicolored Asian ladybeetle in its hivernation process. Durieux D., Fischer C., Lognay G., Vandereycken A., Joie E., Haubruge E. and Verheggen F.J. (in prep.)


Macrosite’s choice Contrasting elements (Nalepa, 2005) Whitish and light-colored objects (Obata, 1986)

Microsite’s choice temperature photoperiod thigmotactism,…

12

PHYSICAL FACTORS : PREVIOUS STUDIES


presence of congeners

luminosity of shelters

PHYSICAL FACTORS

13Aggregation behaviour of Harmonia axyridis adults in non-wintering conditions Durieux D., Deneubourg J.L., Brostaux Y., Vandereycken A., Joie E., Haubruge E. and Verheggen F.J. (in prep.)

shelter

arena 2 tested parameters:

- The luminosity of shelters- The presence of congeners

binary choice experiment

1 ladybird20 ladybirds50 ladybirds


PHYSICAL FACTORS

14

IMPACT OF CONGENERS

20 ladybirds 50 ladybirds10 min 0.028 * 0.10620 min 0.107 0.002 **30 min 0.007 ** < 0.001 ***40 min 0.108 < 0.001 ***50 min 0.012 * < 0.001 ***

1 h 0.080 < 0.001 ***3h < 0.001 *** < 0.001 ***5h < 0.001 *** < 0.001 ***8h < 0.001 *** < 0.001 ***

P valueobservation times

Generalized linear model comparing the observed distribution with a binomial one


PHYSICAL FACTORS

15

IMPACT OF SHELTER’S LUMINOSITY

0.00

0.20

0.40

0.60

0.80

1.00

10 20 30 40 50 60 180 300 480

prop

ortio

n of

shel

tere

d la

dybi

rds

observation time (in minutes)

transparent shelters dark shelters

***

Binary logistic regression : luminosity : P < 0.001 *** time : P < 0.001 ***


20 ladybirds tested

CONCLUSION

Hydrocarbons are involved in the aggregation To lead congeners towards aggregation sites To ensure the cohesion of the aggregate

There are social interactions between ladybirds even in non-wintering conditions

Ladybirds prefer dark shelters

16


THANK YOU FOR YOUR ATTENTION

PHYSICAL FACTORS

18

IMPACT OF SHELTER’S LUMINOSITY

0.00

0.20

0.40

0.60

0.80

1.00

10 20 30 40 50 60 180 300 480

prop

ortio

n of

shel

tere

d la

dybi

rds

observation time (in minutes)

transparent shelters dark shelters

***

Binary logistic regression : luminosity : P < 0.001 *** time : P < 0.001 *** luminosity * time : P <

0.001 ***

PHYSICAL FACTORS

19

IMPACT OF INDIVIDUALS’ DENSITY

00.10.20.30.40.50.60.70.80.9

1

0 120 240 360 480

mea

n pr

opor

tions

of s

helte

red

lady

bird

s

time (in minutes)

TS_1 ladybird

TS_20 ladybirds

TS_50 ladybirds

CS_1 ladybird

CS_20 ladybirds

CS_50 ladybirds

Transparent shelters (TS)Covered shelters (CS)

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C HEMICAL AND PHYSICAL FACTORS INVOLVED IN THE AGGREGATION BEHAVIOUR OF H ARMONIA AXYRIDIS P ALLAS...

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