City life on fast lanes: Urbanization induces an evolutionary shift towards a faster lifestyle in the water flea Daphnia

Abstract

Multiple species show significant trait shifts in response to urbanization. Yet, the impact of anthropogenic warming linked to the urban heat island effect is remarkably understudied. In addition, the relative contributions of phenotypic plasticity and genetic change underlying trait shifts in response to urbanization are poorly known. A common garden study with the water flea Daphnia magna revealed that both genetic differentiation in response to urbanization and phenotypic plasticity in response to higher rearing temperature (24°C) induced significant parallel multivariate shifts in life‐history strategy along the slow–fast pace‐of‐life axis. Urban animals and animals reared at higher temperatures are characterized by fast maturation, early release of progeny, a smaller size at maturity, increased fecundity and higher performance (given by maximal population growth rate “r”) compared to genotypes isolated from rural ponds and animals reared at lower temperatures, respectively. Evolution in response to urbanization accounted for 30% of the total observed shift in life history and caused a significant change in mean trait values, while plasticity responses to experimental warming were unaltered between urban and rural populations. The total trait change achieved through both plasticity and evolution ranged from 8% to 56% depending on the trait. Our results provide clear evidence for evolution underlying an increase in pace of life of populations in response to urbanization. Given the pivotal role of Daphnia in aquatic ecosystems, this shift potentially feeds back to population structure, top‐down control of algae and food web dynamics in urban freshwater ecosystems. In addition, we argue that adaptation to urban heat islands might render these populations preadapted in a context of future climate change. http://onlinelibrary.wiley.com/doi/10.1111/1365-2435.13184/suppinfo is available for this article.

Socio‐eco‐evolutionary dynamics in cities

“…These models have shown that human socio‐economic and demographic patterns and processes are reflected in infrastructure and other abiotic and biotic features of the urban ecosystem (Schaider, Swetschinski, Campbell, & Rudel, 2019; Tessum et al, 2019). Urban evolution research has simultaneously revealed that these same physical and biological characteristics can influence both the adaptive (Brans & De Meester, 2018; Whitehead et al, 2017) and nonadaptive (Combs et al, 2018; Munshi‐South, 2012) evolution of urban species. Indeed, recent work has shown that urban predictor variables that characterize socio‐economic heterogeneity, such as urban heat islands (Brans & De Meester, 2018) and environmental pollutants (Isaksson, 2015; Reid et al, 2016; Wirgin et al, 2011), can drive physiological and life‐history adaptations in organisms.…”

“…They vary in several intraspecific life-history, behavioural, and physiological traits that can elicit strong ecosystem-level effects. D. magna show reduced body size, higher heat tolerance, faster pace of life, and altered stress physiology in urban populations compared to rural populations, which are most likely adaptations to warmer temperatures (Brans & De Meester, 2018;Brans, Jansen, et al, 2017). Smaller average body size in urban zooplankton communities that include Daphnia can have cascading effects on pond ecosystems (Gianuca, Pantel, & De Meester, 2016).…”

Urbanisation and eutrophication as drivers of morphological and physiological divergence among riverine fish populations

“…In our study, gudgeon from urban rivers had a higher body condition compared to their rural counterparts, which is consistent with a previous study in crustaceans (Brans et al., 2018) and spiders (Lowe et al., 2014). Other studies also showed a smaller size at maturity, and a higher growth rate in urban Daphnia (Brans & De Meester, 2018), probably due to higher temperatures in urban areas (Tüzün et al., 2017). In contrast, we found no relationship between urbanisation and growth nor other traits.…”

Unusual evolution of tree frog populations in the Chernobyl exclusion zone

“…10 generations from the accident), in the CEZ, female tree frogs may start to breed at 2-year age in order to speed up life-history strategy. A shorter generation time may be an adaptive response to cope with the accumulation of damage in stressful environments 87,88 , as those with radioactive contamination.…”