The oceans continue to warm due to rising atmospheric greenhouse gas concentrations. Most climate-change studies of aquaculture species use temperature changes based on coarse-resolution climate models and without considering thermal ranges of an animal. Coarse-resolution climate models are generated by global-scale data, which is insufficient to capture the conditions of coastal areas where most aquaculture activity occurs. Therefore, ocean warming research on coastal organisms requires a more comprehensive design to include broad temperature gradients. By using the ecologically and commercially important coastal whelk Rapana venosa, we combined long-term and short-term experiments and selected 4 temperature treatments (19, 23, 27, and 30°C) to simulate different scenarios to test ocean warming effects on growth rates and foraging performances of whelks. We found that elevated temperature within the whelk’s thermal range (23 and 27°C) significantly increased growth rates and enhanced foraging performances of marine whelks when compared to the current temperature (19°C). Conversely, the whelk’s performance collapsed at 30°C in terms of both growth and foraging behavior. Our research clearly shows that local conditions and the tolerance range of a species must be considered to develop meaningful information for testing the effects of a changing climate. Our study suggests that rapa whelks may increase their feeding and reach larger sizes during warmer periods. Moreover, our study may provide a foundation for future climate research on aquaculture species.

Adaptation to novel ecological niches is known to be rapid. However, how ecological divergence translates into reproductive isolation remains a consequential question in speciation research. It is still unclear how coupling of ecological divergence loci and reproductive isolation loci occurs at the genomic level, ultimately enabling the formation of persistent species. Here, we investigate the genomic underpinning colonization of a new niche and formation of two host races in Tephritis conura peacock flies that persist in sympatry. To uncover the genomic differences underlying host plant adaptation, we take advantage of two independent sympatric zones, where host plant specialists using the thistle species Cirsium heterophyllum and C. oleraceum co-occur, and address what regions of the genome that diverge between the host races in a parallel fashion. Using Population Branch Statistics, dxy and BayPass we identify 2996 and 3107 outlier regions associated with host use among western and eastern Baltic populations, respectively, with 82% overlap. The majority of outliers are located within putative inversions, adding to the growing body of evidence that structural changes to the genome are important for adaptations to persist in face of gene flow. Potentially, the high contents of repetitive elements could have given rise to the inversions, but this remains to be tested. The outlier regions were enriched for genes involved in e.g. metabolism and morphogenesis, potentially due to the selection for processing different metabolites, and changes in size and ovipositor length respectively. In conclusion, this study suggests that structural changes in the genome, and divergence in independent ecological functions may facilitate the formation of persistent host races in face of gene flow.