Latitude-specific urbanization effects on life history traits in the damselflyIschnura elegans

Abstract

Many species are currently adapting to cities at different latitudes. Adaptation to urbanization may require eco-evolutionary changes in response to temperature and invasive species that may differ between latitudes.Here, we studied single and combined effects of increased temperatures and invasive alien predator presence on the phenotypic response of replicated urban and rural populations of the damselflyIschnura elegansand contrasted these between central and high latitudes.Larvae were exposed to temperature treatments (current [20 ºC], mild warming [24 ºC], and heat wave [28 ºC; for high latitude only]) crossed with the presence or absence of chemical cues released by the spiny-cheek crayfish (Faxonius limosus), only present at the central latitude. We measured treatment effects on larval development time, mass, and growth rate.Urbanization type affected all life history traits, yet these responses were often dependent on latitude, temperature, and sex. Mild warming decreased mass in rural and increased growth rate in urban populations. The effects of urbanization on mass were latitude-dependent, with central-latitude populations having a greater phenotypic difference. Urbanization effects were sex-specific with urban males being lighter and having a lower growth rate than rural males. At the current temperature and mild warming, the predator cue reduced the growth rate, and this independently of urbanization level and latitude of origin. This pattern was reversed during a heat wave in high-latitude damselflies.Our results highlight the context-dependency of evolutionary and plastic responses to urbanisation, and caution for generalizing how populations respond to cities based on populations at a single latitude.

The genomic response to urbanization in the damselfly Ischnura elegans

“…However, these differences could also stem from geographically varying interaction between urbanization and other environmental factors the damselflies face. Indeed, the results of a common‐garden experiment carried out by Palomar et al (2023) indicated that urban I. elegans , and especially males, were lighter and had a lower growth rate than rural individuals and that these phenotypic changes partially depended on the sampling latitude and rearing temperature. Such phenotypic variation was associated with adjustment of damselfly life history to warmer urban conditions likely imposing weaker seasonal time constraints and hence reduced larval growth rate compared to rural damselflies (Palomar et al, 2023; Tüzün, Op de Beeck, & Stoks, 2017).…”

“…For example, a recent study on larvae of I. elegans and its prey Daphnia magna provided evidence for cryptic eco‐evolutionary feedback masking the effects of adaptation to urbanization, at the same time confirming an adaptive response of I. elegans to urbanization (Brans et al, 2022). Furthermore, there is evidence that the phenotypic adaptation to urbanization might be temperature and latitude‐dependent (Palomar et al, 2023), increasing the levels of complexity in the study of urban adaptation in ectotherms. Studies of other highly mobile animals, including insects such as bumblebees (Theodorou et al, 2018) indicate that the genomic signal of adaptation to urbanization is often detectable despite the risk of dampening local adaptation through maladaptive gene flow (Lenormand, 2002).…”

“…We included multiple urban and rural populations in three geographic regions, southern and northern Poland, and southern Sweden. This allowed us to test whether parallel signals of urban–rural differentiation are detectable at the level of individual SNPs or genomic regions, or whether the patterns of genomic differentiation between the rural and urban populations are largely region‐specific as phenotypes suggest (Palomar et al, 2023). Finally, we tested whether any functional categories were enriched among the genes located in the proximity of candidate urbanization SNPs.…”

Global warming intensifies the interference competition by a poleward-expanding invader on a native dragonfly species

“…How the impact posed by biological invasions to ecosystems change with warming is an important global issue, but it is very difficult to predict whether the impact will be severe or mild owing to the complexity of its process and mechanisms (e.g. [57]). On the other hand, our finding that 'threats by poleward-expanding species that invade from warmer regions become severe with warming' would be applied to other cases of biological invasions attributed to global warming.…”

Latitude‐specific urbanization effects on life history traits in the damselfly Ischnura elegans

“…The dataset containing the phenotypic data is included in Table S3 and is available on Figshare https://doi.org/10.6084/m9.figshare.23708748.v2 (Palomar et al, 2023 ).…”