Data from: The diet of Myotis lucifugus across Canada: assessing foraging quality and diet variability

Variation in prey resources influences the diet and behaviour of
predators. When prey become limiting, predators may travel farther to find
preferred food or adjust to existing local resources. When predators are
habitat limited, local resource abundance impacts foraging success. We
analysed the diet of Myotis lucifugus (little brown bats) from Nova Scotia
(eastern Canada) to the Northwest Territories (north-western Canada). This
distribution includes extremes of season length and temperature and
encompasses colonies on rural monoculture farms, and in urban and
unmodified areas. We recognized nearly 600 distinct species of prey, of
which ≈30% could be identified using reference sequence libraries. We
found a higher than expected use of lepidopterans, which comprised a range
of dietary richness from ≈35% early in the summer to ≈55% by late summer.
Diptera were the second largest prey group consumed, representing ≈45% of
dietary diversity early in the summer. We observed extreme local dietary
variability and variation among seasons and years. Based on the species of
insects that were consumed, we observed that two locations support prey
species with extremely low pollution and acidification tolerances,
suggesting that these are areas without environmental contamination. We
conclude that there is significant local population variability in little
brown bat diet that is likely driven by seasonal and geographical changes
in insect diversity, and that this prey may be a good indicator of
environment quality.