Kasja Malkoc

Quantifying variation in physiological plasticity
I am broadly interested in the mechanisms and consequences of animal responses to changing environmental conditions, with a particular focus on key physiological traits. My research centers on phenotypic plasticity in physiological traits, which refers to the ability of single genotypes or individuals to alter trait expression in response to changes in their internal or external environment.
I primarily investigate physiological traits that are highly labile and sensitive to environmental changes, functioning to maintain homeostasis during perturbations by managing energy fluxes within the organism. These traits include plasma concentrations of key metabolic hormones (such as glucocorticoids and thyroid hormones), metabolic rates at both the organismal and cellular levels, and indices of blood carrying capacity. I study how these traits are expressed when animal populations encounter ecologically relevant challenges, such as sudden cold spells or increased workload periods.
To explore variation in these traits' plasticity across multiple hierarchical levels — from populations to among- and within-individuals — I employ a multi-level and multivariate approach using reaction norms and random regression statistical models.

Investigating multivariate and multidimensional physiological plasticity and its implications
Additionally, I am interested in the mechanisms driving variation in physiological plasticity, including differences among and within individuals in multivariate plasticity (i.e., do individuals differ in how their plastic responses in one trait correlate with responses in another? And, do these correlated responses change within individuals when repeatedly exposed to different environmental challenges?)
Importantly, as I place my research in the context of current global change, I also study whether physiological traits can exhibit multidimensional plasticity, whereby they plastically adjust their expression in response to multiple environmental factors acting simultaneously, which more closely represents the real nature of today´s ecological challenges.
Finally, I complement these analyses by evaluating the evolutionary relevance of variation in physiological plasticity, linking it to fitness, and determining its adaptive value in an era marked by unprecedented environmental change.