An invasive species: Harmonia axyridis (Harlequin ladybird)
Harmonia axyridis (Coleoptera: Coccinellidae) originates from Asia (probably China) and it has been introduced into many countries as an efficient biological control agent to limit aphid populations in glasshouses, gardens and field crops. However, some of these introduced populations have escaped control and are currently being observed to spread in the wild, in North America and Europe. They can be found in various habitats (crops, conifer forests, wetlands etc.). They are most commonly found on deciduous trees (e.g. Acer, Platanus, Tilia) or low-growing plants like nettles. H. axyridis is now perceived as an invasive species. This species has strong dispersal capabilities and has been recorded as making long-distance migrations to overwintering sites. Long-term population surveys performed in North America have shown that H. axyridis could seriously affect the abundance of native ladybird species. H. axyridis is a very efficient aphidophagous insect but it has also a very large prey-range. It can feed on other invertebrates, in particular on other beneficial insects (including European species of ladybirds, such as Adalia bipunctata and Coccinella septempunctata). In addition, it has been observed that in late summer, H. axyridis could feed on fruits (e.g. pears) causing blemishes. In the EPPO region, H. axyridis is now apparently established in Belgium (2001), Germany (2000), Netherlands (2002), United Kingdom (2004). It presence is also recorded in Egypt, France, Greece, Luxemburg but no data is given on its potential establishment or invasiveness in these countries. There is now a debate on whether H. axyridis should still be sold as a biological control agent. As an example, in France the wild strain is no longer multiplied but a particular strain of H. axyridis (wingless) has been selected.
Sources
Anonymous (2005) Het Veelkleurig Aziatisch Lieveheersbeestja [Harmonia axyridis (Pallas)] in Nederland. Nieuwsbrief Plantenziektenkundige Dienst, no. 2, p 1.
Duff A (2005) Wildlife reports. Beetles. British wildlife, 16(4), 282-284.
Katsoyannos P, Kontodimas DC, Stathas GJ, Tsartsalis CT (1997) Establishment of Harmonia axyridis on Citrus and some data on its phenology in Greece. Phytoparasitica 25(3), 183-191.
INTERNET
Belgian forum on invasive alien species. Harmonia axyridis.
http://www.biodiversity.be/bbpf/forum/invasion/species/harmonia.html
CABI Crop Protection Compendium
www.cabicompendium.org/cpc
National Harmonia axyridis survey (UK)
www.harlequin-survey.org