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The black sparrowhawk (Accipiter melanoleucus) is a color-polymorphic sub-Saharan raptor, with adults occurring in two discrete color morphs: dark and light. It has previously been suggested that plumage coloration is determined by a one-locus two-allele system, with the light allele being dominant over the dark allele. Here, we revisit that assumption with an extended dataset of 130 individuals and pedigree information from 75 individuals spanning five generations. We test the observed offspring phenotypic ratio against the expected ratio under the Hardy–Weinberg equilibrium and find significant deviations from the expected values. Contrary to the previous assumption, our data indicate that the dark allele is in fact dominant over the light allele. Similarly, the multigenerational pedigrees obtained are incompatible with a one-locus two-allele system, where the light allele is dominant but are consistent with a scenario where the dark allele is dominant instead. However, without knowledge of the underlying molecular basis of plumage polymorphism, uncertainty remains, and the intra-morph variation observed suggests that modifier genes or environmental factors may also be involved. Our study not only provides a foundation for future research on the adaptive function of color polymorphism in the species but also highlights the need for caution when drawing conclusions about the mode of inheritance in wild animal populations in the absence of genetic data, especially when one color variant is numerically much rarer than the other.

The circadian clock, an internal timekeeping mechanism, allows plants to anticipate regular changes in the environment, such as light and dark, and biotic challenges such as pathogens and herbivores. Here, we demonstrate that the plant circadian clock influences susceptibility to the necrotrophic fungal pathogen, Botrytis cinerea. Arabidopsis plants show differential susceptibility to B. cinerea depending on the time of day of inoculation. Decreased susceptibility after inoculation at dawn compared to night persists under constant light conditions and is disrupted in dysfunctional clock mutants, demonstrating the role of the plant clock in driving time-of-day susceptibility to B. cinerea. The decreased susceptibility to B. cinerea following inoculation at subjective dawn was associated with faster transcriptional reprogramming of the defence response with gating of infection-responsive genes apparent. Direct target genes of core clock regulators were enriched among the transcription factors that responded more rapidly to infection at subjective dawn than subjective night, suggesting an influence of the clock on the defence-signalling network. In addition, jasmonate signalling plays a crucial role in the rhythmic susceptibility of Arabidopsis to B. cinerea with the enhanced susceptibility to this pathogen at subjective night lost in a jaz6 mutant.