No water, no eggs: insights from a warming outdoor mesocosm experiment

Insects are susceptible to dehydration and change in atmospheric humidity
could affect their fitness. To understand the impacts of humidity changes
on insect’s reproductive fitness we released an outcrossed Drosophila
melanogaster population to outdoor mesocosm units and tracked their
fecundity over ninety days under progressively developing summer season.
The study was carried out in a tropical urban garden. Often temperature
has been found to be the key player in changes in reproductive output in a
considerable number of laboratory based studies. Our work suggested that
temperature and humidity interactions determine the physiological state of
an organism which could untimely impact organismal fitness in a given
environmental set-up. This work suggested that fecundity in Drosophila
populations was significantly influenced by relative humidity and its
interaction with temperature. This together suggested that while
temperature was an important parameter for fecundity, relative humidity
individually and in combination with temperature also played an important
role for fecundity in Drosophila. Thus, the combination of temperature and
relative humidity was a better metric to predict the fecundity in
Drosophila populations than considering these parameters individually
under natural conditions. It clearly indicated that future warming events
could drastically impact insects’ reproductive output.