Vortrag, 6th European Mosquito Control Association Workshop (EMCA), Budapest (Hungary): 12.09.2011 - 15.09.2011
The interplay between global warming and invasive arthropods is of outmost interest for possible expansion of vector-borne infectious diseases. Whereas introduction and spread of vector species is often supported by human activities such as trade and traffic, colonization and mainly establishment with successful reproduction is dependent on suitable habitat conditions. Up to now, mostly the effects of warm temperature on the population dynamics of mosquito vectors during the phase of activity have been considered. However, especially cold temperatures seem to be the important ecological constraint regarding possible range expansions and shifts to higher latitudes due to climate change and the growing evidence that extreme cold temperature events will increase. The key factor for the establishment of Aedes albopictus at higher latitudes is therefore its ability to produce cold tolerant diapausing eggs under distinct environmental conditions. During this stage the eggs are considered to be more resistant to environmental extremes. For the first time the low temperature constrains of European diapausing and non diapausing Ae. albopictus eggs were examined systematically under laboratory conditions. Furthermore, a tropical strain of Ae. albopictus and Aedes aegypti were considered. First results suggest that (1) the magnitude of cold tolerance of eggs differs between temperate and tropical strains. (2) Cold tolerance increases in diapausing eggs. (3) Duration of freezing has a minor impact on cold tolerance compared to the magnitude of freezing. These findings support our understanding concerning potential future risk areas for the establishment of the disease vector in the face of a rapidly changing European climate, which in turn can be considered as baselines for surveillance and control activities.