Research interests

• Reproductive biology of the edible dormouse
• Energetic constraints on reproduction
• Fitness and life-history trade-offs
• Evolution of litter size

 

 

Scientific projects

 
The aim of my project is to examine the reproductive biology of the edible dormouse and to explain the occurrence of extreme fluctuation in reproductive output and reproductive failures. The edible dormouse (Glis glis L.) the largest representative of the Gliridae, is relatively common in southern Germany. Where it is therefore possible to study its extraordinary way of life and reproductive biology in detail. Edible dormice are obligate hibernators and have an unusual „life history“. A lifetime up to 11 years in the wild is extraordinarily long for a small mammal. In Germany edible dormice give birth to maximally one litter each year with on average 5-6 juveniles. Edible dormice exhibit strong fluctuation of reproductive output with complete synchronized reproductive failure which is unique in small mammals. In this field study reasons for these unusual and strong reproductive fluctuations are investigated. Especially factors affecting the reproductive activity of the edible dormice are examined and consequences of reproductive skip on the individual „fitness,“ are characterized. The study site is located in southern Germany, where demographic and ecological data have been recorded since 1993. Due to the long term field study, it is possible to investigate the reproduction of a single individual in the detail and to quantify individual reproductive success. In order to examine energetic reproductive costs and their consequences morphometric measurement are taken as well as metabolic and body temperature measurements and feeding experiments are carried out.

Publications

Kager T, Fietz J (2009) Food availability in spring influences reproductive output in the seed-preying edible dormouse (Glis glis). Can J Zool 87 555-565

Fietz J, Kager T, Schauer S (2009) Is energy supply the trigger for reproductive activity in male edible dormice (Glis glis)? J Comp Physiol B 179:829-837