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

2. C ONTEXT AGGREGATION annoyance from their number tainting walls and curtains allergic reactions asthma urticaria rhinitis cough,… conjunctivitis ISCE, Durieux D. et al.

3. C ONTEXT Migratory flight Macrosite choice Microsite choice Physical factors Chemical factors ? ISCE, Durieux D. et al.

4. C HEMICAL FACTORS : P REVIOUS STUDIES Volatile compounds Pyrazines (al Abassi et al., 1998) (-)- β-caryophyllene Emission by H. axyridis in wintering conditions (Brown et al., 2006) the seven spotted ladybird, Coccinella septempuctata Attractive and aggregative potential (Verheggen et al., 2007) ISCE, Durieux D. et al.

5. C HEMICAL FACTORS 1 6 2 3 45 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) ISCE, Durieux D. et al.

6. C HEMICAL FACTORS 1 6 2 3 45 After 8 hours: Test χ² (chi-square of goodness-of-fit test) : P < 0,001 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) ISCE, Durieux D. et al.

7. C HEMICAL FACTORS 1 6 2 3 45 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) ISCE, Durieux D. et al. hexane

8. C HEMICAL FACTORS 1 6 2 3 45 After 8 hours: Test χ² (chi-square of goodness-of-fit test) : P < 0,001 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) The chemical blend ensures the cohesion of the aggregate ISCE, Durieux D. et al.

9. C HEMICAL FACTORS 9 Test χ² (chi-square of goodness-of-fit test) : P = 0.024 for females and P < 0.001 for males 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) Y-olfactometer ISCE, Durieux D. et al. Study of a potential trail

10. C HEMICAL FACTORS 10 Test χ² (chi-square of goodness-of-fit test) : P = 0.001 for females and P = 0.002 for males 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) Y-olfactometer The chemical blend leads congeners towards the aggregate ISCE, Durieux D. et al. Hexane

11. C HEMICAL FACTORS 11 Identification of compounds by GC-MS analyses Saturated hydrocarbons Unsaturated hydrocarbons – one double bond Unsaturated hydrocarbons – two double bonds Aggregation blend Trail 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.) ISCE, Durieux D. et al.

12. Macrosite’s choice Contrasting elements (Nalepa, 2005) Whitish and light-colored objects (Obata, 1986) Microsite’s choice temperature photoperiod thigmotactism,… 12 P HYSICAL FACTORS : PREVIOUS STUDIES ISCE, Durieux D. et al. presence of congeners luminosity of shelters

13. P HYSICAL FACTORS 13 Aggregation 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 ladybird 20 ladybirds 50 ladybirds ISCE, Durieux D. et al.

14. P HYSICAL FACTORS 14 I MPACT OF CONGENERS Generalized linear model comparing the observed distribution with a binomial one ISCE, Durieux D. et al.

15. P HYSICAL FACTORS 15 I MPACT OF SHELTER ’ S LUMINOSITY Binary logistic regression : luminosity : P < 0.001 *** time : P < 0.001 *** ISCE, Durieux D. et al. 20 ladybirds tested

16. C ONCLUSION 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 ISCE, Durieux D. et al.

17. T HANK YOU FOR YOUR ATTENTION

18. P HYSICAL FACTORS 18 I MPACT OF SHELTER ’ S LUMINOSITY Binary logistic regression : luminosity : P < 0.001 *** time : P < 0.001 *** luminosity * time : P < 0.001 ***

19. P HYSICAL FACTORS 19 I MPACT OF INDIVIDUALS ’ DENSITY Transparent shelters (TS) Covered shelters (CS)