In temperate climates, the recurring seasonal exigencies of winter represent a fundamental physiological challenge for a wide range of organisms. In response, many temperate insects enter diapause, an alternative developmental program, including developmental arrest, that allows organisms to synchronize their life cycle with seasonal environmental variation. Geographic variation in diapause phenology contributing to local climatic adaptation is well documented. However, few studies have examined how the rapid evolution of a suite of traits expressed across the diapause program may contribute to climatic adaptation on a contemporary timescale. Here, we investigate the evolution of the diapause program over the past 35 years by leveraging a “natural experiment” presented by the recent invasion of the Asian tiger mosquito, Aedes albopictus, across the eastern United States. We sampled populations from two distinct climatic regions separated by six degrees of latitude (~700 km). Using common-garden experiments, we identified regional genetic divergence in diapause-associated cold tolerance, diapause duration, and post-diapause starvation tolerance. We also found regional divergence in non-diapause thermal performance. In contrast, we observed minimal regional divergence in non-diapause larval growth traits and at neutral molecular marker loci. Our results demonstrate rapid evolution of the diapause program and imply strong selection caused by differences in winter conditions.

Files included in this repository: Simulated_winter_cold_tolerance.csv -- Replicate-level hatch data for samples in simulated winter conditions (data for Figure 2) Rapid_cold_shock_tolerance.csv -- Replicate-level data for rapid cold shock tolerance (data for Figure 3) Diapause_incidence_and_duration.csv -- Replicate-level measurements of diapause incidence from 14 - 175 dpov (data for Figure 4A) Larval_starvation_tolerance.csv -- Individual larva-level data for post-diapause starvation tolerance experiment (data for Figure 4B) Adult_chill_coma_recovery.csv -- Replicate-level adult chill coma recovery time measurements (data for Figure 5) Pairwise_Fst_by_distance.csv -- Population vs population Fst values and geographic distances (data for Figure 6) Larval_growth_data.csv -- Individual-level data for age of pupation and mass at pupation mosquitoes_bam_output.tar.gz -- BAM output for all 365 individual mosquito microhaplotype samples sequenced in this study. mosquito_gtseq1_2_q30mean10dp10maf001_noIndels.recode.vcf -- Processed variant call file for microhaplotypes mosquito_targets_prelim192.fasta -- 192 sequences targeted for microhaplotype sequencing Haplotypes_by_individual.csv -- Haplotypes assigned by locus for each individual sample Haplotype_id_sequences.csv -- Key for haplotype IDs in the Haplotypes_by_individual.csv file