Influence of reproduction on thermoregulation, food intakeand foraging strategies of free-ranging female and male Daubenton`sbat, Myotis daubentonii. Balancing the energy demand ofreproduction in bats requires specific physiological andbehavioural adaptations. Part of this thesis thus focussed on theuse of daily torpor in M. daubentonii during colder ambienttemperatures and reduced food availability,an aspect that stronglyinfluences foetal development and probably also spermatogenesis butthat has been little studied to date for free-ranging bats. Thisalso applies for a detailed knowledge about food intake andforaging behaviour of female and male bats during differentreproductive periods. Insectivorous Daubenton s bat is selected asstudy species because it is rather common and its characteristicflight low over water surfaces facilitates identification andobservations of its feeding behaviour in the field. Myotisdaubentonii is widely distributed in the Palaearctic regionthroughout Europe and Asia.