Response to MHC-based olfactory cues in a mate choice context in two species of darter (Percidae: Etheostoma).

Mate choice is hypothesized to play an important role in maintaining high diversity at major histocompatibility complex (MHC) genes in vertebrates. Many studies have revealed that females across taxa prefer the scent of males with MHC genotypes different to their own. In this study we tested the "opposites-attract" hypothesis in two species of darter with known differences in female criteria used in mate choice: in the fantail darters (a paternal-care species), females prefer males with visual traits related to nest guarding and egg tending, while in rainbow darters (not a paternal-care species) female mate choice criteria are unknown. In dichotomous mate-choice trials, we presented females of both species with the scents of conspecific males with MHC class IIb genotypes that were either similar or dissimilar to that of the focal female. We evaluated the proportion of time each female spent with each male and calculated the average strength of female preference for both species. Female fantail darters demonstrated a preference for the scent of males with similar (rather than dissimilar) MHC genotypes, but this result was not statistically significant. Rainbow darter females showed no preference for the scent of males with similar or dissimilar MHC genotypes. Our results do not support the "opposites-attract" hypothesis in darters.

State-specific prevalence of current e-cigarette use by disability status and disability type-United States, BRFSS 2016-2018.

BACKGROUND: Cigarette smoking is the leading cause of preventable disease and death in the United States. The tobacco product landscape has diversified to include electronic cigarettes (e-cigarettes). Adults with disabilities are more likely than adults without disabilities to smoke cigarettes, but within the current body of literature, there is limited information on the use of e-cigarettes among adults with disabilities. OBJECTIVE: To assess overall and state-specific prevalence of current e-cigarette use among adults by disability status, disability type, sex, and age. METHODS: Disability was defined as having serious difficulty with vision, hearing, mobility, cognition, or any difficulty with self-care or independent living. The Behavioral Risk Factor Surveillance System cross-sectional survey data (2016-2018; n = 1,150,775) were used to estimate state and District of Columbia prevalence of current e-cigarette use among adults (aged ≥18 years) with and without disabilities, overall and by disability type, sex, and age group. RESULTS: Median prevalence of current e-cigarette use was higher among adults with than without disabilities (6.5% vs. 4.3%, P < 0.05). Among adults with disabilities, use varied from 2.5% in DC to 10.0% in Colorado; median use was highest among those with cognitive disabilities (10.0%) and those aged 18-24 years (18.7%). CONCLUSIONS: Prevalence of current e-cigarette use was higher among adults with than without disabilities and varied across states by disability status, type, and age group. The findings underscore the need to monitor e-cigarette use among adults with disabilities and specifically include them in tobacco control policies and programs addressing e-cigarette use.