Filtered phytoplankton movement data

A prerequisite for the survival and reproduction of organisms is to
successfully navigate thermal environmental conditions that unfold over
time and space. While effective movement behaviour has been highlighted as
a key mechanism by which organisms and populations may persist amidst the
backdrop of directional environmental warming, it remains unclear how
behavioural plasticity may mediate such effects, particularly across
timescales that span multiple generations. Here, we examine the capacity
for transgenerational plasticity to alter the movement behaviour of the
motile green algae Chlamydomonas reinhardtii in response to changes in
thermal conditions. We first acclimated C. reinhardtii populations to
thermal environments near (25°C), below (12.5°C), or above (37.5°C) the
temperature range that maximizes population growth rates. Subsequently, we
assayed the micro-spatial scale movement behaviour of these populations in
thermally homogeneous environments across a period of two weeks in each
respective environment, with the goal of evaluating the influence of
thermal history on movement behaviour in a novel thermal environment.
These results indicate that thermal history can mediate the movement
patterns of C. reinhardtii individuals for up to ten generations and that
the trajectory by which phenotypes converge on their acclimated values can
be highly non-linear.  Subsequently, we demonstrated – using a
dispersal assay in spatially variable environments – that thermal
acclimation history can additionally alter movement patterns at
ecologically relevant scales. Collectively these findings indicate the
possibility for transgenerational plasticity to modify behaviour across
extended timescales and converge on acclimated states via non-linear
trajectories. Understanding the efficacy of behaviour for navigating novel
thermal environments, such as environments anticipated amidst
environmental warming, may thus require considering past as well as
present environmental conditions.