Data from: Night warming on hot days produces novel impacts on development, survival and reproduction in a small arthropod

1. An asymmetric increase of nighttime temperatures on hot days is one of
the main features of global climate change. But the biological effects of
an increased nighttime temperature combined with high daytime temperature
are unclear. 2. We used six thermal regimens to simulate nighttime
temperatures on hot days and investigated the effects of night warming on
life history traits of the English grain aphid Sitobion avenae.
Experimental temperatures fluctuated in continuous diurnal cycles,
increasing from 27 °C to a maximum 35 °C and then declining to 27 °C
gradually before further dropping to different minima (13, 16, 19, 21, 23
or 25 °C) representing nighttime temperatures. 3. When compared to
expectations based on constant temperatures, night warming raised the
optimum temperature for development by 3 °C, in contrast to results from
experiments where temperature variability was altered symmetrically or in
a parallel manner. Night warming also reduced aphid survival under heat
from 75% to 37%, and depressed adult performance by up to 50%. Overall,
night warming exacerbated the detrimental effects of hot days on the
intrinsic rate of population increase, which was predicted to drop by 30%
when nighttime minimum temperatures exceeded 20 °C. 4. Our novel findings
on development challenge the ‘Kaufmann effect’, suggesting this is
inapplicable to night warming likely to be encountered in nature. Although
many average temperature models predict increasing pest outbreaks, our
results suggest that outbreaks of some species might decrease due to the
effects of night warming on population dynamics.