Talk, EMCA Symposium - Status of Mosquito Control in Europe with Special Emphasis on Wetlands and Exotic Mosquitoes, Speyer: 2016-03-13 - 2016-03-15
Aedes albopictus, an invasive mosquito and multi-competence vector of Dengue, Chikungunya and Zika (laboratory vector-competence in a mosquito population of Singapore), is currently expanding its range from southern Europe northwards. Spreading of this mosquito is facilitated by human transport and travel and changing climatic conditions allow the establishment at new places. Invasive species tolerate a wide range of environmental conditions (ecological competence), show an increased adaptability to cope with new conditions and thus impede monitoring and control measurements. In temperate regions, the winter cold temperature is thought to be an important limiting factor for the further spread of the species. Here we measured the hatching success of Ae. albopictus eggs after a cold treatment in climate chambers taking into account for the first time diurnal temperature variations. The eggs were exposed to three different mean daily temperature cycles with each 0°C, 5°C, 10°C temperature difference. After 24, 48, 72 and 96 hours we removed the eggs and then determined hatching after 24, 48 and 72 hours, respectively. By the means of boosted regression trees the relative influence of minimum temperature, duration of minimum temperature and temperature difference within the daily cycle was identified. Overall, these three factors explained 89% of the variance within the resulting hatching of larvae. The minimum temperature has the main influence on the survival of eggs after cold treatment with a relative explanation of 61%, whereas the duration of the minimum temperature and temperature difference within the daily cycle reach 19% and 20%, respectively. Hatching success under different cold treatments will be shown. Taking into account diurnal temperature variations rather than constant temperatures in cold experiments support a more realistic picture of winter survival and hatching success of Ae. albopictus eggs in temperate regions, and thus may support monitoring and control measurements.