Male ornamentation is usually costly and may show trades-offs with other life-history traits such as paternal care, which can subsequently affect female preference. Studies on female mate choice have mostly examined how mate-choice cues differ in their expression or ability to be detected in different environmental contexts. However, less focus has been placed on examining how external forces affect female preferences. The purpose of this study was to explore how parental investment strategy and mate choice were mediated by ambient temperature. Specifically, we examined how male ornamentation characteristics and subsequent female incubation investment were impacted by ambient temperature in four plover populations that were breeding across an environmental gradient. We discovered that larger males had more ornamented plumage in warmer conditions, and they were favored by larger females who invested an elevated time into incubation. In contrast, in cooler conditions, males' body size and the color of their ornaments were inversely associated, and females showed weak preference for males with more colorful ornaments. These results imply that female preference for male ornament can change in response to ambient temperature and demonstrate that female preference for male ornamentation may be limited in harsher conditions with higher parental care expenses.

Whether individuals migrate or not is rapidly shifting in many populations. Exactly how and why environmental change alters migration propensity is not well understood. We conducted a systematic literature review to gain insights into the mechanisms that affect the propensity to migrate. Motivated by findings from our literature review, we constructed density-dependent structured population models to explore the coexistence of migrants and non-migrants, when they coexist, and when they do not. We find that carrying capacity in a seasonal environment determines the dominant type in the population. Partial migration can be maintained, or not, depending on where in the life cycle density-dependent operates. Bet-hedging also promotes partial migration. Our study disentangles density-dependence and density-independence in seasonal environments, providing insights into the coexistence of polymorphism, potentially explaining the rapid change in migration strategy observed.

Simple sequence repeats (SSRs) are widely used genetic markers in ecology, evolution and conservation even in the genomics era, while a general limitation to their application is the difficulty of developing polymorphic SSR markers. Next-generation sequencing (NGS) offers the opportunity for the rapid development of SSRs; however, previous studies developing SSRs using genomic data from only one individual need redundant experiments to test the polymorphisms of SSRs. In this study, we designed a pipeline for the rapid development of polymorphic SSR markers from multi-sample genomic data. We used bioinformatic software to genotype multiple individuals using resequencing data, detected highly polymorphic SSRs prior to experimental validation, significantly improved the efficiency and reduced the experimental effort. The pipeline was successfully applied to a globally threatened species, the brown-eared pheasant (Crossoptilon mantchuricum), which showed very low genomic diversity. The 20 newly developed SSR markers were highly polymorphic, the average number of alleles was much higher than the genomic average. We also evaluated the effect of the number of individuals and sequencing depth on the SSR mining results, and we found that ten individuals and ~10X sequencing data were enough to obtain a sufficient number of polymorphic SSRs, even for species with low genetic diversity. Furthermore, the genome assembly of NGS data from the optimal number of individuals and sequencing depth can be used as an alternative reference genome if a high-quality genome is not available. Our pipeline provided a paradigm for the application of NGS technology to mining and developing molecular markers for ecological and evolutionary studies.