Thomas, S M; Obermayr, U; Fischer, D; Kreyling, J; Beierkuhnlein, C: Low-temperature threshold for egg survival of a post-diapause and non-diapause European aedine strain, Aedes albopictus (Diptera: Culicidae), Parasites & Vectors, 5(100) (2012), doi:10.1186/1756-3305-5-100 [Link]
Abstract:

Background: The interplay between global warming and invasive arthropods in temperate zones is of utmost interest in terms of the potential expansions of vector-borne diseases. Up to now, investigations on the recent establishment of mosquito vectors have focused on temperatures during their phases of activity. However, cold temperatures may also act as a strong ecological constraint. Projected changes in winter climate indicate an increase of mean minimum temperatures of the coldest quarter, less frequent days with frost and a shorter frostseason in Europe at the end of the century. Nevertheless, single cold extremes are also expected to persist under warming scenarios, which have a strong impact on reproduction success.

Methods: Here, the temperature constraints of European Aedes albopictus eggs, which had passed through a diapause, compared to non-diapausing eggs were examined systematically under controlled laboratory conditions. Additionally, one tropical strain of Ae. albopictus and of Ae. aegypti was used in the comparison.

Results: The lower temperature threshold tolerated by the European eggs of Ae. albopictus which have undergone a diapause, was -10°C for long term exposures (12 and 24h) and -12°C for 1h exposure. Non-diapausing eggs of European Ae. albopictus were found to hatch after a -7°C cold treatment (8, 12 and 24h exposure). Both tropical aedine species only tolerated the long term treatment at -2°C. Neither Ae. albopictus nor Ae. aegypti eggs hatched after being exposed to -15°C. Survival was mainly influenced by temperature (F = 329.2, df = 1, p<0.001), whereas the duration of the cold treatment only significantly influenced the hatching response at the thermal limits of survival (F = 5.6, df = 1, p = 0.031) but not at 0°C (F = 0.1, df = 1, p = 0.730). Hatching success after the cold treatment was significantly increased in European eggs, which have undergone a diapause compared to non-diapausing eggs (F = 14.7, df = 3, p<0.001). These results illustrate rapid adaptation.

Conclusions: Here, low temperature thresholds for aedine mosquito egg survival were detected. The compilation of risk maps for temperate regions can substantially be improved by considering areas where an establishment of a vector population is unlikely due to winter conditions.

Upcoming ...

Ökologisch-Botanischer Garten:
Su. 2018-09-02
Darauf fliegen Vögel: Früchte und ihre Ausbreitung
Fr. 2018-09-07
Mit tausend Schritten durch die Erdgeschichte: Gesteine im ÖBG
Su. 2018-09-16
Der ÖBG zum Kennenlernen: Allgemeine Gartenführung
Su. 2018-09-23
Konzert: Matinee im Garten mit dem Blockflötenensemble der Städtischen Musikschule Bayreuth unter Leitung von Heinz-Ulf Hertel
Workshop:
Th. 2018-10-11
BayCEER Workshop 2018
Weather research site
Luftdruck (356m): 976.4 hPa
Lufttemperatur: 15.8 °C
Niederschlag: 0.0 mm/24h
Sonnenschein: <1 h/d
Wind (Höhe 17m): 1.8 km/h
Wind (Max.): 5.0 km/h
Windrichtung: SW

...more
Globalstrahlung: 0 W/m²
Lufttemperatur: 14.3 °C
Niederschlag: 0.0 mm/24h
Sonnenschein: <1 h/d
Wind (Höhe 32m): 4.7 km/h
Wind (Max.): 8.7 km/h

...more
This site makes use of cookies More information