Evidence for phenotypic plasticity in brain size and the size of different brain parts is widespread, but experimental investigations into this effect remain scarce and are usually conducted using individuals from a single population. As the costs and benefits of plasticity may differ among populations, the extent of brain plasticity may also differ from one population to another. In a common garden experiment conducted with three‐spined sticklebacks (Gasterosteus aculeatus) originating from four different populations, we investigated whether environmental enrichment (aquaria provided with structural complexity) caused an increase in the brain size or size of different brain parts compared to controls (bare aquaria). We found no evidence for a positive effect of environmental enrichment on brain size or size of different brain parts in either of the sexes in any of the populations. However, in all populations, males had larger brains than females, and the degree of sexual size dimorphism (SSD) in relative brain size ranged from 5.1 to 11.6% across the populations. Evidence was also found for genetically based differences in relative brain size among populations, as well as for plasticity in the size of different brain parts, as evidenced by consistent size differences among replicate blocks that differed in their temperature.

Accurately predicting species’ responses to anthropogenic climate change is hampered by limited knowledge of their spatiotemporal ecological and evolutionary dynamics. We combine landscape genomics, demographic reconstructions, and species distribution models to assess the eco-evolutionary responses to past climate fluctuations and to future climate of an Afro-Palaearctic migratory raptor, the lesser kestrel (Falco naumanni). We uncover two evolutionarily and ecologically distinct lineages (European and Asian), whose demographic history, evolutionary divergence, and historical distribution range were profoundly shaped by past climatic fluctuations. Using future climate projections, we find that the Asian lineage is at higher risk of range contraction, increased migration distance, climate maladaptation, and consequently greater extinction risk than the European lineage. Our results emphasise the importance of providing historical context as a baseline for understanding species’ responses to contemporary climate change, and illustrate how incorporating intraspecific genetic variation improves the ecological realism of climate change vulnerability assessments.

The Karpathos water frog (Pelophylax cerigensis) is classified as Critically Endangered according to the IUCN Red List and its distribution is restricted on the island of Karpathos, South Aegean Sea. Utilizing a next generation sequencing approach, we obtained whole mitochondrial genomes of P. cerigensis to determine the species phylogenetic position within the genus Pelophylax and to clarify the phylogenetic relationship between the species’ population on Karpathos Island and the population of P. cf. bedriagae from the neighboring Rhodes Island. High-throughput sequencing generated mean ± SD = 227 945 ± 18 306 reads averaged per sample. High quality reads were assembled resulting in the complete mitogenome of P. cerigensis of a total size of 17 922 bp. Mitogenome organization was similar to other Pelophylax species, comprising of 13 Protein Coding Genes (PCGs), 22 tRNAs, two rRNAs and one Control Region. Overall mean genetic distance for the 13 PCGs, within the Ranidae family, ranged from 8.01% (COIII) to 11.6% (ATP8), while ratios of synonymous and non-synonymous substitutions were <1 in all the 13 PCGs, indicating purifying selection. Maximum Likelihood and Bayesian Inference analyses based on the concatenated sequences of 13 PCGs and two rRNAs (12S and 16S), showed that individuals from Karpathos and Rhodes form a well-supported monophyletic group with low genetic distance between them (p-distance = 0.1%). Hence, the Rhodes populations seem to belong to P. cerigensis and not to P. bedriagae as formerly thought, highlighting the need for revision of P. cerigensis current conservation status as well as further examination of the P. bedriagae species group.