Projects per year
The Asian ladybird Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) is regarded as an invasive species in many parts of the world. In a previous study we hypothesised that H. axyridis enters diapause at the end of October and then shifts to a quiescent state in December in northwestern Europe. In the present study we test this idea of a short, early period of diapause by sampling beetles from their hibernation sites immediately after their migratory flights in October, subsequently keeping them in outdoor cages, and then, after certain time-intervals, measuring the pre-oviposition time under optimal egg-laying laboratory conditions at 25 degrees C. We did this at both short (12L) and long (16L) photoperiods, since a photoperiodic response is an indicator of true diapause, rather than quiescence. A significant, albeit small, difference in pre-oviposition period between the two photoperiods, which disappears in December, corroborates our earlier hypothesis that the ladybirds are in a state of diapause until mid-December. Compared with that of native ladybirds the diapause of H. axyridis generally is relatively short and weak; moreover, it appears to have become shorter over the last decade. This flexibility in diapausing behaviour may be an important factor that contributes to the invasive success of H. axyridis.
- lady beetle
- photoperiodic response
- winter survival
Establishment of the aphidophagous ladybird beetle Harmonia axyridis in The Netherlands: successful aphid control or ecological disaster?
14/04/08 → 8/10/14
Raak-van den Berg, C. L., de Jong, P. W., Hemerik, L., & van Lenteren, J. C. (2013). Diapause and post-diapause quiescence demonstrated in overwintering Harmonia axyeidis (Coleoptera: Coccinellidae) in northwestern Europe. European Journal of Entomology, 110(4), 585-591. https://doi.org/10.14411/eje.2013.079