Better Conversations With Parkinson's: Feasibility and Acceptability of a Novel Communication Partner Training Telehealth Intervention.

Studying historical and contemporary selection acting on genomes in wild populations can provide insight into the evolutionary trajectories of these populations and species. Comparative between‐species studies can detect strong single or potentially long episodes of recurrent positive selection within the phylogenetic history of the analysed species, whereas population‐based approaches are designed to detect recent or ongoing positive selection (Gao ). Just by chance, the latter approach applied at a single time point (sampling event) will more often detect long episodes of potentially recurrent selection than unique single selection events in evolutionary history. A combination of population‐based and phylogenetic approaches is therefore ideal to test for recurrent selection in the recent and long‐term history. Recurrent ongoing selection has been described in dynamic conflict situations such as co‐evolutionary arms races in host–parasite systems or intra‐ and intersexual conflicts. For example, coevolution between hosts and their parasites is expected to follow an arms race leading to recurrent allele fixations in their genomes (Tellier et al. ; Cooper et al. ). Similarly, postcopulatory sexual selection and sexual conflict can lead to rapidly and repeatedly evolving genes involved in reproduction (Swanson and Vacquier ; Clark et al. ; Wong ). For example, in mammals and birds the observed rapid evolution in the testis is likely explained by positive selection on genes associated with sperm competition (Ramm et al. ; Birkhead and Montgomerie ; Murat et al. ). Sperm competition can result in rapid evolution of reproductive traits related to the female and male reproductive fluid, but also to the assembly, morphology, motility and longevity of the sperm itself (Simmons and Wedell ). Multiple studies in birds have investigated the interplay between sperm competition and testis size, sperm morphology and motility (Birkhead and Montgomerie ). A meta‐analysis on data stemming mostly from birds and mammals revealed that selection under sperm competition favours longer sperm heads, midpieces and flagella (Lüpold et al. ). Given that the flagellum is the component propelling the sperm forward and the midpiece the part generating the necessary energy, this is consistent with the predicted selection for faster sperm (Humphries et al. ). However, the molecular underpinnings of the selection associated with sperm competition in birds are understudied. It has been shown that a sex‐linked supergene controls sperm length and velocity in a songbird (Kim et al. ). However, studies from mammals and suggest high variability in the targets of selection between lineages (Wong ; Simmons and Wedell ). Our study adds information about single genes and their potential functions related to sperm competition in another bird lineage. Our general aim was to use a genomic approach to investigate selection in a bird species known to be under strong sexual selection. Specifically, we first investigated signatures of recent selection in a population of the pectoral sandpiper () to assess whether there is detectable rapid evolution in genes related to intense competition for matings and fertilizations. Strong sexual selection through intense male–male competition is indicated by the pronounced sexual size dimorphism in this species, with males being much larger than females (Lesku et al. ). Strong male–male competition is also associated with around‐the‐clock activity, whereby more active males sire more offspring (Lesku et al. ), and intense breeding site sampling across a large geographical scale (Kempenaers and Valcu ). Females of the pectoral sandpiper often mate with multiple males, resulting in a considerable proportion of clutches fertilized by multiple males (27.0% of  = 230 complete clutches, our unpublished data). Compared to other socially monogamous shorebirds, pectoral sandpipers also have relatively long sperm (Johnson and Briskie ), a trait that relates positively to the intensity of sperm competition (Lüpold et al. ).