“Seasonality rate alters acclimation of performance under climate change”

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Viktor Nilsson-Örtman and Frank Johansson

Acclimation is more beneficial when seasonal changes in temperature are slow

Keeping up with the seasons pays off at mid-latitudes, where seasons change slowly

Many plants and animals can fine-tune their physiology with the changing seasons. This type of flexibility, known as acclimation, enables individuals to move, feed, and grow better in the cold of winter and in the warmth of summer. Previously, acclimation was believed to be more beneficial in highly seasonal environments near the poles. However, new research performed at Umeå University has revealed that acclimation is especially advantageous in the gently changing seasons at mid-latitudes.

In their earlier work, Viktor Nilsson-Örtman and Frank Johansson had noted how high-latitude environments warm up faster in spring and cool down faster in fall compared to lower-latitude environments. Previous research had shown that acclimation is a relatively slow process. This inspired the question: could temperatures change so rapidly over the year at high latitudes that it prevents individuals from acclimating?

To answer this question, the researchers reared larval damselflies – small and slender relatives of dragonflies – under the slowly changing seasons typical of central Europe and the rapidly changing seasons typical of northern Sweden. By comparing how different species grew in each climate with predictions from a theoretical model, they found that acclimation was indeed less successful when the seasons changed as rapidly as in northern Sweden. In other words, when temperatures change slowly, it pays off to change with the seasons. But when temperatures change fast, as in northern Sweden, damselflies cannot keep up, so their physiology remain relatively unchanged throughout the year.

These results indicate that mid-latitude climates favor species that are physiologically more flexible than tropical and polar climates. They also highlight how climate change can have consequences for biodiversity not only by increasing the earth’s temperature, but by changing the timing of the seasons. Read the Article

A shallow pond in Central Europe with abundant aquatic vegetation where damselflies lay their eggs (left). Coenagrionid damselfly larva feeding on brine shrimp in the laboratory (right). (Credit: Viktor Nilsson-Örtman)