Wednesday, October 26, 2011

Established: The Harlequin Ladybird

Harlequin Ladybird (Harmonia axyridis var. succinea) adult at site of establishment near Cork city
Our recent record of the Harlequin Ladybird (Harmonia axyridis) prompted me to reexamine some older pictures of Coccinellidae beetles, to see if any other of the morphs had inadvertently been seen. Lo and behold, buried among the pictures of moths, flowers and wading birds, there was an example of H. axyridis var. succinea. However, this was just one picture among about 25 taken. The rest showed no more adults, but, worryingly, did show many, many pupae as well as larvae. These pictures taken on the 19th of October, 2010 show the first evidence of establishment of H. axyridis in Ireland. 
Harlequin Ladybird (Harmonia axyridis) pupa at site of establishment near Cork city
The site of establishment is a collection of Griselinia littoralis bushes that border a footpath and that is backed by a small stream on a previously heavily industrialised area about 2 km from Cork city centre. The area is quite near the river Lee, Cork city's main river, and also near Tivoli Dock, a major container port that may be the site of entrance for H. axtridis. Examination of the site last week, just over a year after the first sighting, showed H. axyridis pupae still present on the same G. littoralis bushes, showing that it survived the unprecedently harsh weather last winter, something that has been observed in other countries such as Belgium (1). This is not the only site, with another being reported from Co. Carlow in July of this year. Establishment of H. axridis in Ireland is worrying, as they have had adverse effects on other Coccinellidae species where introduced in North America, reducing numbers by up to 20 times in some cases (2). They have also been seen to cause damage through feeding to soft fruits (grapes) and pears.
Harlequin Ladybird (Harmonia axyridis) larva at site of establishment near Cork city
  1. Berkvens et al., 2010. Journal of Insect Physiology 56 pp. 438-444
  2. Kock, 2003. Journal of Insect Science, 3 pp. 1-16

No comments:

Post a Comment