Mats Ittonen FD

Species distributions are limited by the availability of suitable habits. Species ranges can shift either when range margin populations adapt to new conditions, or when previously unsuitable habitats become suitable, e.g. as a result of climate change. Range shifts can lead to strong natural selection on life history traits.

I study the wall brown butterfly (Lasiommata megera), which has recently expanded northwards in Sweden. I am interested in how the butterflies adapt to the new conditions they face in their new range. An important part of the life cycle of most temperate insects is winter diapause, a resting stage that allows correct timing of growth and reproduction to the summer. To time the start of diapause, most insects use day length as a cue: shortening days indicate that winter is near, while long days mean that there is still time to grow and reproduce. When expanding northwards, insects will face a different photoperiodic system from what they have adapted to further south.

I want to find out if and how southern and northern Swedish populations of the wall brown have adapted locally. My work includes laboratory experiments to assess differences in diapause induction and fitness during and after diapause, as well as field transplant experiments to study these differences and their fitness consequences in more natural conditions. I will also sample genomic differences among populations and look for genomic signs of evolution.