Nutrition in pregnant big brown bats (Eptesicus fuscus) feeding on June beetles

We investigated whether a diet of a commonly eaten insect, June beetles (Phyllophaga rugosa), could meet the daily nutritional requirements of pregnant big brown bats, Eptesicus fuscus. In mid-pregnancy, ingestion of 34 culled June beetles meets daily caloric requirement and yields intakes of water, magnesium ([Mg.sup.2+]), potassium ([K.sup.+]), and nitrogen (N) that meet or exceed nutritional needs. Sodium ([Na.sup.+]) and total iron intake are marginally adequate, and calcium ([Ca.sup.2+]) intake is 10 times below estimated requirements.