Data from: Humidity stress and its consequences for male pre- and post-copulatory fitness traits in an insect

Global declines in insect abundance are of significant concern. While
there is evidence that climate change is contributing to insect declines,
we know little of the direct mechanisms responsible for these declines.
Male fertility is compromised by increasing temperatures, and the thermal
limit to fertility has been implicated as an important factor in the
response of insects to climate change. However, climate change is
affecting both temperature and hydric conditions, and the effects of water
availability on male fertility have rarely been considered. Here we
exposed male crickets Teleogryllus oceanicus to either low- or
high-humidity environments while holding temperature constant. We measured
water loss and the expression of both pre- and post-mating reproductive
traits. Males exposed to a low-humidity environment lost more water than
males exposed to a high-humidity environment. A male’s cuticular
hydrocarbon profile (CHC) did not affect the amount of water lost, and
males did not adjust the composition of their CHC profiles in response to
hydric conditions. Males exposed to a low-humidity environment were less
likely to produce courtship song or produced songs of low quality. Their
spermatophores failed to evacuate and their ejaculates contained sperm of
reduced viability. The detrimental effects of low humidity on male
reproductive traits will compromise male fertility and population
persistence. We argue that limits to insect fertility based on temperature
alone are likely to underestimate the true effects of climate change on
insect persistence, and that the explicit incorporation of water
regulation into our modelling will yield more accurate predictions of the
effects of climate change on insect declines.