Science Facing Aliens - Invasive Alien Species in Belgium - Belgian ...

Adaline (µg) ± S.E.
2.50
2.00
1.50
1.00
0.50
0.00
0.0004 µg ± 0.0007
t 9= -4.62; p= 0.001
1.67 µg ± 1.14
Contact Bite
(n=10)
(n=10)
Figure 3. Adaline in H. axyridis larvae after contact with, or after biting a A. bipunctata
larva.
Quantity of adaline (µg)
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
0 24 48 72 96 120 144 168 192 216 240
Time after ingestion (h)
R 2 =0.615
p < 0.0001
(n =10) (n =10) (n =10) (n = 8)
pupae
(n =10) (n =9) (n = 9)
imago
exuviae
Figure 4. Temporal change of adaline measured in H. axyridis larvae after consumption of
one first instar A. bipunctata.
Field results
In 2005, 28 H. axyridis larvae were sampled in potato fields in Belgium and analyzed by GC-
MS. Nine larvae out of 28 were positive. Three alkaloids were detected: precoccinelline (n=4
larvae), propyleine (n=4) or adaline and precoccinelline (n=1), indicating that the larvae had
attacked and consumed native species such as C. septempunctata, P. quatuordecimpunctata
and A. bipunctata.
Conclusion
29