Photos by Felix Sperling, Marjo Saastamoinen, Susu Rytteri and Suvi Ikonen

We seek to understand how habitat fragmentation and environmental variation shapes intraspecific differences in life history traits in natural populations. We are also interested in identifying genomic regions associated with key performance-related traits, and to assess how their allele frequencies vary across space and time and affect the dynamics of natural populations.

Severity, frequency, and unpredictability of environmental change has increased dramatically in recent years due to human caused phenomena, such as habitat fragmentation, habitat degradation and climate change. Species in the wild are constantly experiencing stress due to this environmental variation, for example, when their resource availability becomes limited or they experience sub-optimal thermal conditions. We aim to assess variation in the possible strategies that allow individuals to cope with such environmental stresses in wild populations. We couple laboratory and field-based studies with molecular approaches to unravel the significance of different mechanisms – genetics and intestinal microbial communities – potentially influencing individual responses to environmental challenges. At the moment, we focus on the influence of host plant quality as an environmental stressor, which is known to greatly influence life histories in many organisms.

The main study organism is Meliatae cinxia butterfly but we also work with other butterflies, namely Bicyclus anynana and Heliconius species in collaboration with researchers from UCL, Université Catholique de Louvain, Cambridge and Sheffield.

Habitat loss and fragmentation are one of the major threats to biodiversity. Our work aims at understanding ecological and genetic consequences of habitat fragmentation using the Glanville fritillary (Melitaea cinxia) butterfly metapopulation as a study system. The system is exceptional as more than twenty years of large-scale survey data exists from the metapopulation. The ecological data at the landscape level together with the extensive genomic resources available provide excellent base for the wide range of ecology, genomics and population dynamics studies. The aim of the genomic studies is to identify genomic regions associated with key performance (fitness, life-history and flight) related traits, and to assess how allele frequencies (in e.g. dispersal related genes) vary across space and time and affect the dynamics of the system. We have also broadened our approach from metapopulation modeling to landscape genetics by better taking into account landscape features in the spatial modeling.

Parasites and pathogens are pervasive in nature. Infections often reduce individual’s performance and have substantial fitness costs, therefore investment to a functional immune defence is a crucial component of individual’s life history. In this project, we have focused on understanding how ecological factors, such as resource quality, density or thermal conditions, influence individual’s investment in immune defence in the Glanville fritillary butterfly, and how this translates into variation in other life history traits. We have shown how environmental conditions during different life-stages may work as predictive cues in guiding individual's later life immune responses in an adaptive way but also demonstrate how sometimes the responses seem maladaptive. We are also using molecular and genomic tools to assess the role of genetic variation in shaping immune defence as a response to developmental or adult stress.

Dispersal is a process of crucial importance for the ecological and evolutionary dynamics of populations, due to its consequences for gene flow and demography. It is also a key life-history trait in organisms living in spatially structured populations, including the Glanville fritillary butterfly, as it allows individuals to move between habitats and to establish new populations, which is a requirement for the long-term survival of the metapopulation. Variation in dispersal, its' influence on other life history traits, the genomic regions shaping the observed variation as well as how the spatial dynamics affect this variation have been the key interests of our research. During the last few years most of the work related to dispersal has been synthesizing across species the Costs of Dispersal and the Genetics of Dispersal together with a European level network of researchers.

In 2017, we became part of the Research Centre for Ecological Change that unites leading experts in the field to utilize long-term series of ecological data to understand impacts of global change.