No water, no mating: Connecting dots from behaviour to pathways

Insects hold considerable ecological and agricultural importance making it
vital to understand the factors impacting their reproductive output.
Environmental stressors are examples of such factors which have a
substantial and significant influence on insect reproductive fitness.
Insects are also ectothermic and small in size which makes them even more
susceptible to environmental stresses. The present study assesses the
consequence of desiccation on the mating latency and copulations duration
in tropical Drosophila melanogaster. We tested flies for these
reproductive behavioral parameters at varying body water levels and with
whole metabolome analysis in order to gain a further understanding of the
physiological response to desiccation. Our results showed that the
duration of desiccation is positively correlated with mating latency and
mating failure, while having no influence on the copulation duration. The
metabolomic analysis revealed three biological pathways highly affected by
desiccation: starch and sucrose metabolism, galactose metabolism, and
phenylalanine, tyrosine and tryptophan biosynthesis. These results are
consistent with carbohydrate metabolism providing an energy source in
desiccated flies and also suggests that the phenylalanine biosynthesis
pathway plays a role in the reproductive fitness of the flies. 
Desiccation is a common issue with smaller insects, like Drosophila and
other tropical insects, and our findings indicate that this lack of
ambient water can immediately and drastically affect the insect
reproductive behaviour, which becomes more crucial because of
unpredictable and dynamic weather conditions.