Funded by LBAYS: Investigating Glanville Fritillary Butterflies' Adaptation to Climate Change

Embarking on a PhD journey, Nadja Verspagen delved into the intricate world of Glanville fritillary butterflies. From diverse European origins, these butterflies undergo controlled climate experiments, unveiling population variations. Unraveling their complex life cycle, this research illuminates the mechanisms behind their adaptation to varying climates, providing insights into their response to future environmental changes.

In March 2020 I arrived at Lammi Biological Station, where I was planning to stay for most of the coming 3 Months to perform the first set of experiments for my PhD. I aim to research the potential of insects to adapt to climate change, and for this I use Glanville fritillary butterflies (Melitaea cinxia) originating from different places across Europe. By rearing these individuals from different climates (From Finnish ones used to cold temperatures, all the way to Spanish ones, that are used to much warmer conditions) under controlled temperatures in the laboratory, we can see if there are differences between populations. This will help understand mechanisms behind adaptation to different climates, and thus also understand how these butterflies might respond to future climate change.

Glanville fritillary butterflies have a complex life cycle: they hatch from the eggs as small caterpillars, that go through 5 instars before going to diapause for the winter. After diapause, they go through 2 more instars and then pupate after which adults eclose from the pupae, who lay eggs, and the cycle can start again. These different life stages and accompanying strategies allow us to study the effects of environmental stress on each one of them.

During the spring, I planned to rear Spanish post-diapause larvae, who originate from different climates within Spain to adulthood at different temperatures to see if there would be differences in mass, development time, wing patterns or flight metabolic rate. Besides that, I also planned to rear offspring from Finnish, Estonian, French and Spanish butterflies from egg to diapause at different temperatures and monitor the mass increase, development time and fat content of the larvae. These were big plans for one spring: Detailed experiments like this provide a lot of information, but also require much work. Besides weighing more than 3000 small caterpillars (some of them multiple times) and taking pictures of their wings, the animals also have to be checked and fed with fresh Ribwort Plantain (Plantago lanceolata) leaves every day. In order to make this possible, I worked with a great team of two research assistants and a BSc student.

All of us were ready and excited to start the experiments, but two weeks after starting the COVID-19 pandemic broke loose. This brought great uncertainty and many questions: “will we be able to continue the experiments?” “Even just take care of the butterflies?” “Will we be able to visit home?” “What if one of us gets ill?”. Luckily, due to the remote nature of Lammi Biological Station and the fact that we were already present, we could continue doing our experiments and no butterflies had to be abandoned. With strict restrictions on visitors, luckily nobody got ill, but this also meant that all of us stayed at the station for the entire duration of the experiment. A strange situation, in which you all of a sudden become even more focused on the research, but also dependent on each other. I have memories of staying in quarantine together with the entire family of “Lammi people”. Of working long days in the lab and once-a-week grocery trips on Friday evening. Of thinking about experiments, and private sauna nights, and of endless walks in the beautiful Lammi forests on days off and swims in the lake after work.

Doing research during a pandemic is not simple and provided many challenges but with some luck and hard work by many people I managed to complete all of my planned experiments. Analysing the data takes perhaps even more time than performing the experiments and thus not all of the results are in yet, but the first graphs look very promising and give plenty of ideas for new research next year. Hopefully then in better circumstances, although every bad situation has a silver lining: I definitely had the best quarantine work, company and location of all!