McManus, C. A. | Search bioRxiv

bioRxiv2026

Urbanization drives parallel shifts in morphology and colouration of Pieris rapae across three cities

Urbanization is a major driver of global environmental change, yet the evolutionary consequences for natural populations remain poorly understood. The cabbage white butterfly, Pieris rapae, is one of few butterfly species that thrives in cities, offering a unique opportunity to investigate whether urbanization drives parallel phenotypic evolution. In this study, we quantified phenotypic divergence between urban and non-urban populations across three independent metropolitan regions (Cleveland, Philadelphia, and Pittsburgh, U.S.), measuring body size, flight morphology, and wing pigmentation and reflectance in >500 field-caught individuals from 19 sites. Across regions, we found repeated reductions in overall body size and relative thorax mass in urban butterflies of both sexes, along with reduced relative forewing area in urban males, suggesting sex-specific impacts on mobility. Wing pigmentation showed limited urban-associated variation, but we detected novel sexual dimorphism in near-infrared reflectance within urban populations. Together, these results demonstrate repeatable divergence between urban and non-urban butterfly populations across multiple trait axes and suggest that plastic responses to urban stressors previously documented in experimental work manifest as consistent phenotypic shifts in natural populations.

ecology↗

bioRxiv2022

Cell-type-specific whole-genome landscape of ΔFOSB binding in nucleus accumbens after chronic cocaine exposure

The ability of neurons to respond to external stimuli involves adaptations of gene expression. The transcription factor, {Delta}FOSB, is important for the development of drug addiction, however, its gene targets have not been identified. Here we use CUT&RUN to map the genome-wide enrichment of {Delta}FOSB binding in the two major neuronal cell types of the nucleus accumbens, a key brain reward region, after cocaine exposure. The binding landscape shows that the majority of {Delta}FOSB peaks occur outside of promoter regions, including intergenic regions, and are surrounded by epigenetic marks indicative of active enhancers. BRG1, the core subunit of the SWI/SNF chromatin remodeling complex, overlaps with {Delta}FOSB peaks, consistent with earlier studies of {Delta}FOSBs interacting proteins. In addition, in silico analyses predict that {Delta}FOSB cooperatively regulates gene expression with homeobox and T-box transcription factors. These novel findings uncover key elements of {Delta}FOSBs molecular mechanisms in transcriptional regulation.

neuroscience↗