TY  - JOUR
A1  - Joschinski, Jens
A1  - Hovestadt, Thomas
A1  - Krauss, Jochen
T1  - Coping with shorter days: do phenology shifts constrain aphid fitness?
JF  - PeerJ
N2  - Climate change can alter the phenology of organisms. It may thus lead seasonal organisms to face different day lengths than in the past, and the fitness consequences of these changes are as yet unclear. To study such effects, we used the pea aphid Acyrthosiphon pisum as a model organism, as it has obligately asexual clones which can be used to study day length effects without eliciting a seasonal response. We recorded life-history traits under short and long days, both with two realistic temperature cycles with means differing by 2 °C. In addition, we measured the population growth of aphids on their host plant Pisum sativum. We show that short days reduce fecundity and the length of the reproductive period of aphids. Nevertheless, this does not translate into differences at the population level because the observed fitness costs only become apparent late in the individual's life. As expected, warm temperature shortens the development time by 0.7 days/°C, leading to faster generation times. We found no interaction of temperature and day length. We conclude that day length changes cause only relatively mild costs, which may not decelerate the increase in pest status due to climate change.
KW  - Homoptera aphididae
KW  - clock reproduction ecology
KW  - phenotypic plasticity
KW  - phenology shifts
KW  - insect timing
KW  - physiological constraints
KW  - day length
KW  - circadian rhythms
KW  - Acyrthosiphon pisum
KW  - climate change
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-148382
VL  - 3
IS  - e1103
ER  - 
TY  - JOUR
A1  - Cornelius, Christine
A1  - Leingärtner, Annette
A1  - Hoiss, Bernhard
A1  - Krauss, Jochen
A1  - Steffan-Dewenter, Ingolf
A1  - Menzel, Annette
T1  - Phenological response of grassland species to manipulative snowmelt and drought along an altitudinal gradient
JF  - Journal of Experimental Botany
N2  - Plant communities in the European Alps are assumed to be highly affected by climate change, as the temperature rise in this region is above the global average. It is predicted that higher temperatures will lead to advanced snowmelt dates and that the number of extreme weather events will increase. The aims of this study were to determine the impacts of extreme climatic events on flower phenology and to assess whether those impacts differed between lower and higher altitudes. In 2010, an experiment simulating advanced and delayed snowmelt as well as a drought event was conducted along an altitudinal transect approximately every 250 m (600–2000 m above sea level) in the Berchtesgaden National Park, Germany. The study showed that flower phenology was strongly affected by altitude; however, there were few effects of the manipulative treatments on flowering. The effects of advanced snowmelt were significantly greater at higher than at lower sites, but no significant difference was found between both altitudinal bands for the other treatments. The response of flower phenology to temperature declined through the season and the length of flowering duration was not significantly influenced by treatments. The stronger effect of advanced snowmelt at higher altitudes may be a response to differences in treatment intensity across the gradient. Consequently, shifts in the date of snowmelt due to global warming may affect species more at higher than at lower altitudes, as changes may be more pronounced at higher altitudes. These data indicate a rather low risk of drought events on flowering phenology in the Bavarian Alps.
KW  - flowering
KW  - advanced
KW  - snowmelt
KW  - Alps
KW  - BBCH
KW  - climate change
KW  - delayed snowmelt
Y1  - 2013
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-126888
VL  - 64
IS  - 1
ER  -