In an age of deepening biodiversity crisis, plant species biological studies integrating ecological and genetic approaches, especially exhaustive studies with a model plant species, are urgently needed for both assessing the present status and implementing effective conservation measures, as a comprehensive understanding of demographic/ genetic interactions involved in the vicious cycle of plant population extinction is a prerequisite for any precise prediction regarding plant conservation. In this article, we summarize the major contributions to conservation ecological studies on a heterostylous clonal herb Primula sieboldii, focusing on gene flow and reproductive success, which are dependent on the life-history traits of the species and biological interactions with its effective pollinators, long-tongued bumblebees.

Flowering phenology and allozyme variation were studied to test the existence of positive assortative mating for flowering time in a natural population of Primula sieboldii E. Morren, a heterostylous perennial herb, consisting of approximately 180 genets in a deciduous forest. There was significant variation in flowering date among genets, but not between heterostylous morphs. The temporal order of the flowering time of genets was fairly constant for the two years of the study. The spatial heterogeneity of light availability at the study site was small during the flowering season of the species. In order to analyze the extent of genetic differentiation between early‐ and late‐flowering genet groups, allozyme diversities were analyzed with 10 loci. The GST between the early‐ and late‐flowering groups was not significantly different from zero. Evidence of positive assortative mating for flowering time was not detected. Prolongation of flowering duration due to pollen limitation may be one important factor preventing the genetic differentiation of early‐ and late‐flowering groups by enhancing the overlap of flowering time among genets.

This is the first report of a linkage map and QTL analysis for floral morphology related to heterostyly in P. sieboldii. Floral morphologies related to heterostyly are controlled by the S locus in LG 7 and by several QTLs in other LGs. Additionally, this study showed that molecular markers are effective tools for investigating morph ratios in a population containing the non-flowering individuals or during the non-flowering seasons.

Understanding of pollination systems is an important topic for evolutionary ecology, food production, and biodiversity conservation. However, it is difficult to grasp the whole picture of an individual system, because the activity of pollinators fluctuates depending on the flowering period and time of day. In order to reveal effective pollinator taxa and timing of visitation to the reproductive success of plants under the complex biological interactions and fluctuating abiotic factors, we developed an automatic system to take photographs at 5-s intervals to get near-complete flower visitation by pollinators during the entire flowering period of selected flowers of Nelumbo nucifera and track the reproductive success of the same flowers until fruiting. Bee visits during the early morning hours of 05:00–07:59 on the second day of flowering under optimal temperatures with no rainfall or strong winds contributed strongly to seed set, with possible indirect negative effects by predators of the pollinators. Our results indicate the availability of periodic and consecutive photography system in clarifying the plant-pollinator interaction and its consequence to reproductive success of the plant. Further development is required to build a monitoring system to collect higher-resolution time-lapse images and automatically identify visiting insect species in the natural environment.

We tested a hypothesis regarding species commonness using a database compiled by a citizen science program called "Tokyo Butterfly Monitoring." The data used were more than 34,000 butterfly records, which were cleansed through expert check after posted by monitoring participants from 2009 to 2017. We hypothesized that butterfly species with multiple annual reproductive cycles and food plants common in city environments are more common and would have more monitoring reports. The generalized linear mixed model (GLMM) analysis revealed significant effects of including "cultivated plants" in the larval food menu and "multivoltinism" on the number of individual species reported, which was compatible with the hypothesis. The species with the most records (12% of all records among 90 species) was Zizeeria maha, which reproduces 5-6 times annually and relies on Oxalis corniculata, a small weed common in urban open spaces. Argyreus hyperbius, a southern species that was very rare before the 1990s, ranked third in the current data. Its major host plant is a common garden plant, the pansy, which grows in most gardens and green spaces. The data collected by the monitoring program appear to represent the status of the butterfly community in Tokyo, a megacity subjected to rapid environmental changes.